CN110649239B - Si-B-C negative electrode material and preparation method, application and negative electrode material, electrode sheet and lithium ion battery containing the same - Google Patents

Abstract

Based on CO₂The prepared silicon-based Si-B-C cathode material and the preparation method and the application thereof belong to the field of preparation of battery cathode materials. The CO-based₂The prepared silicon-based Si-B-C negative electrode material is synthesized in calcium chloride-based or calcium chloride-magnesium chloride-based molten salt by taking a silicon-calcium alloy, carbon dioxide and a boron-containing oxide as raw materials, and can be stirred in an auxiliary manner in the synthesis process, and the synthesized silicon-based Si-B-C negative electrode material is used as a lithium ion battery negative electrode material, so that the specific capacity and the cycle performance of the silicon-based Si-B-C negative electrode material can be improved. And the preparation method has low cost and simple operation.

Description

Si-B-C negative electrode material and preparation method, application, and negative electrode material, battery comprising the same Pole Pieces and Lithium Ion Batteries

technical field

The invention relates to the field of battery anode material preparation, in particular to a silicon-based Si-BC anode material prepared based on CO ₂ , a preparation method and application thereof.

Background technique

Lithium-ion batteries are widely used due to their high energy density, long cycle life, and no memory effect. With the development of new energy vehicles and new energy power generation technologies, lithium-ion power batteries for automobiles and lithium-ion batteries for energy storage have become urgent needs. The current commercial lithium-ion battery anode material is graphite, and its theoretical specific capacity is only 372mAh/g, which is difficult to meet the needs of high-performance, high-capacity lithium-ion batteries. Silicon material has become the focus of research due to its large theoretical specific capacity of 4200mAh/g. However, it suffers from volume expansion effect and low electrical conductivity, which severely limit its capacity-cycling performance.

At present, the methods used to reduce the volume expansion of silicon anode materials for lithium ion batteries include nanometerization, porosity, and doping modification. Studies have shown that silicon particles with a particle size of 100-150 nanometers have good electrochemical properties, but the current cost of nanometerization is high and it is not easy to scale up. In addition, at the same time, it is necessary to adopt a coating method to alleviate the side effects caused by nanometerization. At the same time, the coating treatment is used to buffer the stress caused by the volume expansion, reduce the capacity loss of nano-silicon caused by nanometerization, improve the conductivity between particles, and improve the cycle performance. Among them, carbon coating is one of the effective means. But in the existing silicon-carbon composite materials, most of them are simply mechanical mixing of silicon particles and carbon, or silicon nanoparticles are dispersed in phenolic resin, PVA, citric acid, stearic acid, glucose, sucrose, polyethylene It is calcined and coated in organic carbon sources such as alcohol, polyvinyl chloride and polyethylene glycol. The amorphous carbon formed after calcination isolates the contact between silicon and the electrolyte and improves the stability of the material, but the agglomeration of silicon particles is not easy to disperse, and the electrical conductivity is insufficient, which easily leads to problems such as ohmic polarization. Meanwhile, the preparation process of the above-mentioned silicon-carbon composite material is complicated in process and high in production cost.

In fact, boron can be intercalated into the silicon lattice to widen the interplanar spacing of the silicon crystal, which is beneficial to alleviate the expansion problem after the silicon is intercalated with lithium. And after boron is embedded in the silicon lattice, the conductivity of silicon will increase. All of these are beneficial to solve the problems of poor cycle performance of silicon anode materials for lithium-ion batteries. [Typical literature: Inorg.Chem.2019, 58, 4592-4599] and others have used metal magnesium, 700 ℃ reduction by mixing boron oxide and silicic acid to form boron oxide-silica, prepared boron-containing silicon lithium-ion battery anode material. Magnesium is a strong reducing agent, reduction is an exothermic reaction, and a large amount of heat is released during the reaction process, which will make the oxide raw materials sintered into large particles, which is not conducive to the effective reaction of the reaction, and is not conducive to the control of production, and the consumption of active and expensive metal magnesium big. This method has problems such as high cost, complicated operation, uneven distribution of Si and boron, and large particle size of silicon products.

Some people have used silicon-calcium alloy to directly reduce aluminum chloride (typical literature: NanoResearch2018, 11(12): 6294-6303), nickel chloride (typical literature: Chem.AsianJ.2014, 9, 3130-3135), chlorine Tantalum (typical literature: DaltonTrans., 2017, 46, 3655-3660) and other chloride salts, the generated products are silicon, calcium chloride or chloride salts of calcium and metals, and the products are washed with hydrochloric acid and demineralized to obtain silicon Nanosheets. Silicon-calcium alloy is also a strong reducing agent, reduction is an exothermic reaction, and a large amount of heat is released during the reaction process, which will cause the silicon-calcium alloy to sinter into large particles, which is not conducive to the effective progress and control of the reaction.

To sum up, if we can build a Si-B-C structure in which boron-dissolved silicon is embedded in a grid composed of carbon distribution, it will be beneficial to improve the performance of lithium-ion battery anode materials.

SUMMARY OF THE INVENTION

In view of the problems existing in the prior art, the present invention provides a silicon-based Si-BC negative electrode material prepared based on CO ₂ and a preparation method and application thereof. The silicon-based Si-BC negative electrode material prepared based on CO ₂ is made of silicon calcium Alloy, carbon dioxide and boron-containing oxides are used as raw materials to synthesize silicon-based Si-BC anode materials in calcium chloride-based or calcium chloride-magnesium chloride-based molten salts, and the synthesized silicon-based Si-BC anode materials are used as lithium ions Battery anode material can improve its specific capacity and cycle performance. In addition, the preparation method has low cost and simple operation.

The present invention is achieved through the following technical solutions:

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ , comprising the following steps:

Step 1: Preparation

(1) drying boron-containing oxide and molten salt raw material respectively to remove moisture; wherein, molten salt is: calcium chloride-based molten salt or calcium chloride-magnesium chloride-based molten salt; described boron-containing oxide is oxidized Boron (B ₂ O ₃ ), Borax (Na ₂ B ₄ O ₇ ·10H ₂ O), Calcium Borate (xCaO ·yB ₂ O ₃ ·nH ₂ O), Magnesium Borate (Mg ₂ B ₂ O ₅ ), Potassium Borate One or more mixtures of (K ₂ B ₄ O ₇ ·5H ₂ O);

(2) Under the protection of inert gas, according to the proportions, the silicon-calcium alloy, boron-containing oxide, and molten salt raw materials are respectively ground until the materials are uniform, and then mixed uniformly, and the obtained mixture is sealed;

(3) the mixed material is placed in the embedded crucible of the reactor, and sealed;

(4) in the sealed reactor, feed the inert gas, and maintain the inert atmosphere in the reactor, ensure the positive pressure in the reactor, while feeding the inert gas, the reactor is heated up;

Step 2: Synthesis

When the reactor is heated to the synthesis temperature, keep the temperature constant, introduce CO ₂ into the molten salt of the reactor, ventilate for 1-2 hours, let it stand, and react at a constant temperature for 1-5 hours to obtain the reacted product; wherein, the synthesis temperature is 530 ℃ ～900℃; wherein, the flow rate of CO ₂ is ≤400mL/min;

Step 3: Post-processing

The reacted product was placed in a cooling container for cooling, ground, washed with hydrochloric acid to remove molten salt, filtered, washed with water, and dried to obtain a silicon-based Si-BC negative electrode material prepared based on CO ₂ .

In the step 1 (1), the particle size of the silicon-calcium alloy is 500 μm˜3 mm.

In the described step 1 (1), the calcium chloride-based molten salt is calcium chloride, calcium chloride-sodium chloride, calcium chloride-potassium chloride, calcium chloride-sodium chloride-chloride A kind of potassium, among which, calcium chloride base molten salt, calcium chloride main salt.

Described calcium chloride-magnesium chloride base molten salt is calcium chloride-magnesium chloride, calcium chloride-magnesium chloride-sodium chloride, calcium chloride-magnesium chloride-potassium chloride, calcium chloride-magnesium chloride-potassium chloride-chloride One of sodium, wherein, in the calcium chloride-magnesium chloride-based molten salt, calcium chloride-magnesium chloride is the main salt, in a molar ratio, calcium chloride:magnesium chloride≥1.

In the step 1(1), the process of removing water from the molten salt is as follows: placing the molten salt in a high-temperature vacuum drying furnace, at 300-400° C., under a pressure of -0.1 MPa, and drying for 10-15 hours to remove the adsorbed water and crystal water to obtain dry molten salt raw material.

In the step 1 (1), the process for removing moisture from the boron-containing oxide is: the boron-containing oxide with crystal water: boron oxide (B ₂ O ₃ ), borax (Na ₂ B ₄ O ₇ ·10H) ₂ O), calcium borate (xCaO·yB ₂ O ₃ ·nH ₂ O), magnesium borate (Mg ₂ B ₂ O ₅ ), potassium borate (K ₂ B ₄ O ₇ ·5H ₂ O), one or more The mixture of the species is placed in a high temperature vacuum drying furnace, at 300-400° C., the pressure is below -0.1 MPa, dried for 10-15 hours, and the adsorbed water and crystal water are removed to obtain dry boron-containing oxide raw materials.

In the step 1 (2), the inert gas is one of nitrogen gas, argon gas, or nitrogen-argon gas mixture.

In the step 1 (2), when the molten salt is a calcium chloride-based molten salt, the boron-containing oxide contains boron oxide, in a molar ratio, CaSi ₂ in the silicon-calcium alloy: boron oxide ≥ 3; in a molar ratio, Calcium chloride in calcium chloride-based molten salt: CaSi ₂ in calcium-silicon alloy ≥10;

In the step 1 (2), when the molten salt is a calcium chloride-based molten salt, the boron-containing oxide contains boron oxide, and the preferred molar ratio of CaSi ₂ : boron oxide in the silicon-calcium alloy is (3-5): 1 The preferred molar ratio of calcium chloride: boron oxide in the calcium chloride-based molten salt is 10-12.

In the described step 1 (2), when the molten salt is a calcium chloride-based molten salt, the boron-containing oxide contains calcium borate, taking calcium borate CaB ₂ O ₄ as an example, in molar ratio, CaSi ₂ in the silicon-calcium alloy. : calcium borate ≥ 3; molar ratio, calcium chloride in calcium chloride-based molten salt: calcium borate ≥ 40:3.

In the step 1 (2), when the molten salt is a calcium chloride-based molten salt, the boron-containing oxide contains calcium borate, taking calcium borate CaB ₂ O ₄ as an example, CaSi ₂ in the silicon-calcium alloy: calcium borate is preferred. The molar ratio is (3-5):1; the preferred molar ratio of calcium chloride: calcium borate in the calcium chloride-based molten salt is 14-16.

In the step 1 (2), when the molten salt is a calcium chloride-based molten salt, the boron-containing oxide contains borax, in a molar ratio, CaSi ₂ in the calcium-silicon alloy: borax ≥ 6; in a molar ratio, chlorinated Calcium chloride in calcium-based molten salt: borax ≥ 71:3.

In the step 1 (2), when the molten salt is a calcium chloride-based molten salt, the boron-containing oxide contains borax, and the preferred molar ratio of CaSi ₂ : borax in the silicon-calcium alloy is (6-10): 1; chlorine The preferred molar ratio of calcium chloride:borax in the calcium chloride-based molten salt is 30-32.

In the step 1 (2), when the molten salt is a calcium chloride-based molten salt, the boron-containing oxide contains magnesium borate, in a molar ratio, CaSi ₂ in the silicon-calcium alloy: magnesium borate≥3; in a molar ratio, Calcium chloride in calcium chloride-based molten salt: magnesium borate ≥10.

In the step 1 (2), when the molten salt is a calcium chloride-based molten salt, the boron-containing oxide contains magnesium borate, and the preferred molar ratio of CaSi ₂ : magnesium borate in the silicon-calcium alloy is (3-5):1 The preferred molar ratio of calcium chloride: magnesium borate in the calcium chloride-based molten salt is 10-12.

In the step 1 (2), when the molten salt is a calcium chloride-based molten salt, the boron-containing oxide contains potassium borate, in a molar ratio, CaSi ₂ in the silicon-calcium alloy: potassium borate ≥ 6; in a molar ratio, Calcium chloride in calcium chloride-based molten salt: potassium borate ≥71:3.

In the step 1 (2), when the molten salt is a calcium chloride-based molten salt, the boron-containing oxide contains potassium borate, and the preferred molar ratio of CaSi ₂ : potassium borate in the silicon-calcium alloy is (6-10): 1 The preferred molar ratio of calcium chloride: potassium borate in the calcium chloride-based molten salt is 30-32.

In the step 1 (3), the embedded crucible is a graphite crucible or a nickel crucible.

In the step 1 (4), the inert gas is argon or argon-nitrogen mixed gas, and in the case of argon-nitrogen mixed gas, argon:nitrogen ≥1:1 by volume.

In the step 2, the reactor is heated by a resistance wire furnace, and the heating rate to the synthesis temperature is 3-10° C./min.

In the step 2, the synthesis temperature>the melting temperature of the molten salt raw material+(10-20)°C.

In the step 2, CO ₂ can be a mixed gas of CO ₂ and argon.

In the step 2, after the reactor is heated to the synthesis temperature, the temperature is kept constant, and the stirring paddle can be inserted into the molten salt to maintain stirring during the ventilation and constant temperature reaction, and the stirring paddle rotation speed v is 0<v≤700r/min.

In the step 2, the stirring paddle is completely immersed in the molten salt, and the stirring paddle is driven by a frequency-modulated motor to rotate.

In the step 3, the cooling container is a stainless steel container.

In the step 3, after the reacted product is discharged from the reactor, the reactor is sealed, and at the same time, the resistance wire furnace is lowered to room temperature, and the inert gas is stopped.

In the step 3, a mortar is used for the grinding.

In the step 3, the hydrochloric acid is 0.1-0.2 mol/L hydrochloric acid.

In the step 3, drying is vacuum drying at 50-80°C.

A silicon-based Si-BC negative electrode material prepared based on CO ₂ is prepared by the above preparation method.

The particle size of the silicon-based Si-BC negative electrode material prepared based on CO ₂ is 50 nm-50 μm; when the Si-BC is statically synthesized, the particle size of the product is 1 μm-50 μm; when the Si-BC is synthesized by stirring, The product particle size is 50nm-500nm.

An application of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is used as a negative electrode material for lithium ion batteries.

A negative electrode material, comprising the above-mentioned Si-BC negative electrode material prepared based on CO ₂ .

An electrode sheet, comprising the above-mentioned negative electrode material, the negative electrode material further comprising a binder, a conductive agent and a solvent.

A lithium ion battery, comprising the above-mentioned electrode sheet, a statically synthesized silicon-based Si-BC negative electrode material, the coulombic efficiency of the first charge and discharge is >75%, preferably 78% to 84%, the first discharge specific capacity is 3800mAh/g, and the first discharge capacity is 3800mAh/g. The current density of 0.1A·g ^-1 is cycled for 400 cycles, and its reversible cycling specific capacity is >1200mAh/g, preferably 1230-1520mAh/g; the silicon-based Si-BC anode material synthesized by stirring has a first charge-discharge coulombic efficiency >70% , preferably 74% to 79%, cycle 500 cycles at a current density of 0.1A·g ^-1 , and its reversible cycle specific capacity is >1300mAh/g, preferably 1310-1500mAh/g.

The silicon-based Si-BC negative electrode material prepared based on _CO of the present invention and its preparation method and application, the chemical reaction equation involved in its molten salt is:

Thermodynamic calculations show that: chemical reaction 3CaSi ₂ +B ₂ O ₃ =6Si+2B+3CaO; 2CaSi ₂ +CO ₂ =4Si+C+2CaO; 3CaSi ₂ +CaB ₂ O ₄ =6Si+2B+4CaO, 3CaSi ₂ +Mg ₂ B ₂ O ₅ =6Si+2B+3CaO+2MgO, CaCl ₂ +6CaSi ₂ +Na ₂ B ₄ O ₇ =12Si+4B+7CaO+2NaCl, CaCl ₂ +6CaSi ₂ +K ₂ B ₄ O ₇ =12Si+ 4B+7CaO+2KCl can proceed spontaneously, but it is an exothermic reaction, and the reaction product is difficult to control, especially the particle size of the product and the thoroughness of the reaction. The research shows that calcium silicide alloy has a certain solubility in calcium chloride. Using calcium chloride to dissolve the silicon-calcium alloy to control its reaction rate with boron-containing oxides, and at the same time use calcium chloride molten salt as a solvent to control the growth of product particles, which will be beneficial to control the synthesis process of Si-BC materials and obtain excellent performance. Li-ion battery Si-BC anode material. Therefore, the present invention uses silicon-calcium alloy, carbon dioxide, and boron-containing oxides as raw materials to synthesize Si-BC negative electrode materials for lithium-ion batteries in static or agitated calcium chloride-based or calcium chloride-magnesium chloride-based molten salts. The particle size is controllable, and the reaction can be accelerated, because the prepared calcium oxide can be dissolved in the molten salt, which can promote the reaction and effectively separate the product and the molten salt. The method can control the reaction rate, control the energy release, and promote the reaction to proceed effectively. The prepared silicon-based Si-BC negative electrode material has uniform distribution of silicon, carbon, and boron, moderate particle size, and the prepared lithium-ion battery has good specific capacity and cycle performance, and low cost. And the synthesis process is simple to operate.

The present invention regulates the reaction between the silicon-calcium alloy and carbon dioxide, the reaction between the silicon-calcium alloy and the boron-containing oxide and the generation process of the product Si-B-C material by regulating the salt composition and proportion, the synthesis temperature and the synthesis time. Controlling the reaction rate, promoting the uniform distribution and particle size control of silicon, boron and carbon in the Si-B-C product, is beneficial to effectively alleviate and buffer the volume expansion of the silicon-lithium alloying process as a negative electrode material for lithium-ion batteries, and improve the electrical conductivity of silicon materials. Improve electrochemical performance. The method utilizes low-cost silicon-calcium alloys, boron-containing oxides and carbon dioxide as raw materials to synthesize materials in calcium chloride-based or calcium chloride-magnesium chloride-based molten salts, and realizes low-cost and controlled preparation of lithium-ion batteries Si-B-C Negative electrode material, the operation process is simple. The prepared Si-B-C anode material has uniform distribution of silicon, boron and carbon, moderate silicon particle size, and good specific capacity and cycle performance.

Detailed ways

The present invention will be further described below in conjunction with specific embodiments. It should be understood that these examples are only for the present invention and are not intended to limit the scope of the present invention. It should be understood to the outside that, after reading the content of the present invention, those skilled in the art make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims of the present application.

In the example of the present invention, unless otherwise specified, the raw materials and equipment used are commercially available, and the purity is analytically pure and above; specifically the silicon-calcium alloy, boron-containing oxide, calcium chloride base salt and calcium chloride-magnesium chloride used Various chloride salts of the base salt are commercially available products. The chlorine salt used is of analytical grade. The ceramic mortars, graphite or nickel crucibles used are commercially available.

In the embodiment of the present invention, drying calcium chloride base or calcium chloride-magnesium chloride base salt and boron-containing oxide containing crystal water to remove moisture is to dry calcium chloride base or calcium chloride-magnesium chloride base salt, containing crystal water The boron-containing oxide was placed in a high-temperature vacuum drying furnace, and dried for 12 hours at a temperature of 300 °C and a pressure of -0.1 MPa to remove adsorbed water and crystal water.

In the embodiment of the present invention, the silicon-calcium alloy, calcium chloride base salt and calcium chloride-magnesium chloride base salt are weighed, ground and evenly mixed under the protection of inert gas in a ceramic mortar.

In the embodiment of the present invention, the gas outlet of the reactor extends to below the liquid level in the pool outside the reactor through a pipeline, and when argon gas continues to flow, bubbles emerge.

In the embodiment of the present invention, the heating of the resistance wire furnace is to heat the reactor in the resistance wire furnace.

In the embodiment of the present invention, the synthesis temperature is 10-20° C. higher than the melting temperature of the molten salt.

Example 1

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is carried out according to the following steps:

(1) dry boron oxide and calcium chloride to remove moisture;

(2) Under the protection of inert gas, weigh 6.5g±0.1g of silicon-calcium alloy, weigh 1.5g±0.1g of boron oxide, grind and mix to obtain silicon-calcium alloy-boron oxide;

(3) Under the protection of inert gas, weigh 75.0g±0.1g calcium chloride, and grind it evenly;

(4) uniformly mixing silicon-calcium alloy-boron oxide and calcium chloride to obtain the mixed salt, which is sealed in a ziplock bag;

(5) Put the mixed salt into the graphite crucible embedded in the reactor, and seal the reactor cover.

(6) feed inert gas from the air inlet of the reactor cover, discharge the inert gas from the air outlet of the reactor cover, and ensure that the reactor is positive pressure;

(7) The resistance wire furnace is heated up, and the heating rate is 5 °C/min;

(8) The reactor was heated to 800°C, and the calcium chloride was melted to form molten salt, which was kept warm. At the same time, CO ₂ was introduced into the molten salt from another air inlet of the reactor cover. After ventilating for 2 hours, let stand for 3 hours to obtain The product after the reaction, wherein, the inflow flow of _CO is 300mL/min;

(9) heating up the salt pipe;

(10) After the salt in the salt outlet pipe is melted, the reacted product flows out from the salt outlet by gravity, and is stored in a stainless steel container for cooling.

(11) a small amount of reacted product remains in the salt outlet pipe, stop heating the salt outlet pipe, and the residual reacted product is cooled and automatically seals the salt outlet;

(12) The resistance wire furnace is cooled to room temperature, and the inert gas is stopped.

(13) Take out the cooled salt from the stainless steel container and grind it; wash off the salt with 0.1mol/L hydrochloric acid, filter; wash the filtered product with deionized water; place it in a vacuum drying oven at 60°C and dry to obtain silicon-based Si -B-C negative electrode material, sealed for use;

(14) The prepared silicon-based Si-B-C negative electrode material is made into a lithium ion battery negative electrode for electrochemical testing.

Example 2

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 1, except that:

(1) In step (8), in the molten salt reaction process, the time for introducing CO is _2h , and the time for standing is 5h; other methods are the same.

Example 3

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 1, except that:

(1) In step (8), in the molten salt reaction process, the time for introducing CO is _2h , and the time for standing is 2h; other methods are the same.

Example 4

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 1, except that:

(1) In step (8), in the molten salt reaction process, the time for introducing _CO is 1h, and the time for standing is 2h; other methods are the same.

Example 5

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 1, except that:

(1) In step (8), in the molten salt reaction process, the time for introducing CO ₂ is 1h, and the time for standing is 1h; other methods are the same.

Example 6

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 1, except that:

(1) in step (1), dry boron oxide, calcium chloride, magnesium chloride to remove moisture;

(2) in step (4), under the protection of inert gas, weigh 75.0g ± 0.1g calcium chloride, take 55.0g ± 0.1g magnesium chloride, grind evenly to obtain calcium chloride-magnesium chloride;

(3) in step (5), the silicon-calcium alloy-boron oxide, calcium chloride-magnesium chloride are mixed uniformly, and packed into a self-sealing bag to seal;

(4) In step (8), the reactor is heated to 700° C., calcium chloride-magnesium chloride is melted to form molten salt, the CO2 is introduced for _2h , and the standing time is 3h; other methods are the same.

Example 7

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 6, except that:

(1) In step (8), the time for introducing CO ₂ is 2h, and the time for standing is 2h; other methods are the same.

Example 8

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 6, except that:

(1) In step (8), the time for introducing CO ₂ is 2h, and the time for standing is 1h; other methods are the same.

Example 9

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 6, except that:

(1) In step (8), the time for introducing CO ₂ is 1h, and the time for standing is 2h; other methods are the same.

Example 10

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 6, except that:

(1) In step (8), the time for introducing CO ₂ is 1h, and the time for standing is 1h; other methods are the same.

Example 11

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 1, except that:

(1) in step (1), dry boron oxide, calcium chloride, sodium chloride to remove moisture;

(2) in step (4), under the protection of inert gas, weigh 75.0g ± 0.1g calcium chloride, take 9.9g ± 0.1g sodium chloride, grind evenly to obtain calcium chloride-sodium chloride;

(3) in step (5), the silicon-calcium alloy-boron oxide, calcium chloride-sodium chloride are mixed uniformly, and packed into a self-sealing bag to seal;

(4) In step (8), the reactor is heated to 750° C., calcium chloride-sodium chloride is melted to form molten salt, the CO2 is introduced for _2h , and the standing time is 3h; other methods are the same.

Example 12

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 11, except that:

(1) In step (8), the time for introducing CO ₂ is 2h, and the time for standing is 2h; other methods are the same.

Example 13

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 11, except that:

(1) In step (8), the time for introducing CO ₂ is 2h, and the time for standing is 1h; other methods are the same.

Example 14

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 11, except that:

(1) In step (8), the time for introducing CO ₂ is 1h, and the time for standing is 2h; other methods are the same.

Example 15

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 11, except that:

(1) In step (8), the time for introducing CO ₂ is 1h, and the time for standing is 1h; other methods are the same.

Example 16

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 1, except that:

(1) in step (1), dry and remove moisture by boron oxide, calcium chloride, potassium chloride;

(2) in step (4), under the protection of inert gas, weigh 75.0g ± 0.1g calcium chloride, take 12.6g ± 0.1g potassium chloride, grind evenly to obtain calcium chloride-potassium chloride;

(3) in step (5), the silicon-calcium alloy-boron oxide, calcium chloride-potassium chloride are mixed uniformly, put into ziplock bag and seal;

(4) In step (8), the reactor is heated to 670° C., calcium chloride-potassium chloride is melted to form molten salt, the CO2 is introduced for _2h , and the standing time is 3h; other methods are the same.

Example 17

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 16, except that:

(1) In step (8), the time for introducing CO ₂ is 2h, and the time for standing is 2h; other methods are the same.

Example 18

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 16, except that:

(1) In step (8), the time for introducing CO ₂ is 2h, and the time for standing is 1h; other methods are the same.

Example 19

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 16, except that:

(1) In step (8), the time for introducing CO ₂ is 1h, and the time for standing is 5h; other methods are the same.

Example 20

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 16, except that:

(1) In step (8), the time for introducing CO ₂ is 1h, and the time for standing is 4h; other methods are the same.

Example 21

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 16, except that:

(1) in step (1), dry and remove moisture by boron oxide, calcium chloride, potassium chloride, sodium chloride;

(2) In step (4), under the protection of inert gas, weigh 75.0g±0.1g calcium chloride, 6.3g±0.1g potassium chloride, 5.0g±0.1g sodium chloride, grind evenly, Obtain calcium chloride-potassium chloride-sodium chloride;

(3) in step (5), silicon-calcium alloy-boron oxide, calcium chloride-potassium chloride-sodium chloride are evenly mixed, and packed into a self-sealing bag to seal;

(4) Step (8) The reactor is heated to 630° C., calcium chloride-potassium chloride-sodium chloride is melted to form molten salt, the CO2 is introduced for _2h , and the standing time is 3h; other methods are the same.

Example 22

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 21, except that:

(1) In step (8), the time for introducing CO ₂ is 2h, and the time for standing is 2h; other methods are the same.

Example 23

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 21, except that:

(1) In step (8), the time for introducing CO ₂ is 2h, and the time for standing is 1h; other methods are the same.

Example 24

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 21, except that:

(1) In step (8), the time for introducing CO ₂ is 1h, and the time for standing is 2h; other methods are the same.

Example 25

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 21, except that:

(1) In step (8), the time for introducing CO ₂ is 1h, and the time for standing is 1h; other methods are the same.

Example 26

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 1, except that:

(1) in step (1), dry and remove moisture by boron oxide, calcium chloride, sodium chloride, magnesium chloride;

(2) In step (4), under the protection of inert gas, weigh 75.0g±0.1g calcium chloride, 55.0g±0.1g magnesium chloride, 9.9g±0.1g sodium chloride, grind evenly, and obtain chlorine calcium chloride-magnesium chloride-sodium chloride;

(3) in step (5), silicon-calcium alloy-boron oxide, calcium chloride-magnesium chloride-sodium chloride are evenly mixed, and packed into a self-sealing bag to seal;

(4) In step (8), the reactor is heated to 620° C., calcium chloride-magnesium chloride-sodium chloride is melted to form molten salt, the CO2 is introduced for _2h , and the standing time is 3h; other methods are the same.

Example 27

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 26, except that:

(1) In step (8), the time for introducing CO ₂ is 2h, and the time for standing is 2h; other methods are the same.

Example 28

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 26, except that:

(1) In step (8), the time for introducing CO ₂ is 2h, and the time for standing is 1h; other methods are the same.

Example 29

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 26, except that:

(1) In step (8), the time for introducing CO ₂ is 1h, and the time for standing is 2h; other methods are the same.

Example 30

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 26, except that:

(1) In step (8), the time for introducing CO ₂ is 1h, and the time for standing is 1h; other methods are the same.

Example 31

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 1, except that:

(1) in step (1), dry and remove moisture by boron oxide, calcium chloride, potassium chloride, magnesium chloride;

(2) In step (4), under the protection of inert gas, weigh 75.0g±0.1g calcium chloride, 55.0g±0.1g magnesium chloride, 12.6g±0.1g potassium chloride, grind evenly, and obtain calcium chloride-magnesium chloride-potassium chloride;

(3) in step (5), the silicon-calcium alloy-boron oxide, calcium chloride-magnesium chloride-potassium chloride are evenly mixed, put into a self-sealing bag and seal;

(4) In step (8), the reactor is heated to 590° C., calcium chloride-magnesium chloride-potassium chloride is melted to form molten salt, and the _CO2 time is 2h, and the standing time is 3h, wherein, the _CO2 The inflow flow is 200mL/min; other methods are the same.

Example 32

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 31, except that:

(1) In step (8), the time for introducing CO ₂ is 2h, and the time for standing is 2h; other methods are the same.

Example 33

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 31, except that:

(1) In step (8), the time for introducing CO ₂ is 2h, and the time for standing is 1h; other methods are the same.

Example 34

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 31, except that:

(1) In step (8), the time for introducing CO ₂ is 1h, and the time for standing is 2h; other methods are the same.

Example 35

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 31, except that:

(1) In step (8), the time for introducing CO ₂ is 1h, and the time for standing is 1h; other methods are the same.

Example 36

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 1, except that:

(1) in step (1), dry and remove moisture by boron oxide, calcium chloride, potassium chloride, sodium chloride, magnesium chloride;

(2) In step (4), under the protection of inert gas, weigh 75.0g±0.1g calcium chloride, 55.0g±0.1g magnesium chloride, 6.3g±0.1g potassium chloride, 5.0g ±0.1g sodium chloride, ground evenly to obtain calcium chloride-magnesium chloride-potassium chloride-sodium chloride;

(3) in step (5), the silicon-calcium alloy-boron oxide, calcium chloride-magnesium chloride-potassium chloride-sodium chloride are mixed uniformly, and packed into a self-sealing bag to seal;

(4) In step (8), the reactor is heated to 530 ° C, calcium chloride-magnesium chloride-potassium chloride-sodium chloride is melted to form molten salt, the _CO2 time is 2h, and the standing time is 3h, wherein , the flow rate of CO ₂ is 100mL/min; other methods are the same.

Example 37

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 36, except that:

(1) In step (8), the time for introducing CO ₂ is 2h, and the time for standing is 2h; other methods are the same.

Example 38

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 36, except that:

(1) In step (8), the time for introducing CO ₂ is 2h, and the time for standing is 1h; other methods are the same.

Example 39

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 36, except that:

(1) In step (8), the time for introducing CO ₂ is 1h, and the time for standing is 2h; other methods are the same.

Example 40

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 36, except that:

(1) In step (8), the time for introducing CO ₂ is 1h, and the time for standing is 1h; other methods are the same.

Example 41

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 1, except that:

(1) in step (1), calcium borate, calcium chloride are dried to remove moisture;

(2) in step (2), under the protection of inert gas, weigh 6.5g ± 0.1g of calcium-silicon alloy, weigh 2.8g ± 0.1g of calcium borate, grind and mix to obtain calcium-silicon alloy-calcium borate;

(3) in step (5), the silicon-calcium alloy-calcium borate and calcium chloride are mixed uniformly, packed into a self-sealing bag and sealed;

(4) In step (8), the reactor is heated to 800° C., calcium chloride is melted to form molten salt, the CO2 is introduced for _2h , and the standing time is 3h; other methods are the same.

Example 42

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 41, except that:

(1) in step (1), calcium borate, calcium chloride, magnesium chloride are dried to remove moisture;

(2) in step (4), under the protection of inert gas, take by weighing 38.0g ± 0.1g calcium chloride, take by weighing 28.0g ± 0.1g magnesium chloride, grind evenly to obtain calcium chloride-magnesium chloride;

(3) in step (5), the silicon-calcium alloy-calcium borate, calcium chloride-magnesium chloride are mixed uniformly, put into ziplock bag to seal;

(4) In step (8), the reactor is heated to 700° C., calcium chloride-magnesium chloride is melted to form molten salt, the CO2 is introduced for _2h , and the standing time is 3h; other methods are the same.

Example 43

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 41, except that:

(1) in step (1), calcium borate, calcium chloride, sodium chloride are dried to remove moisture;

(2) in step (4), under inert gas protection, weigh 38.0g ± 0.1g calcium chloride, take 5.0g ± 0.1g sodium chloride, grind evenly to obtain calcium chloride-sodium chloride;

(3) in step (5), the silicon-calcium alloy-calcium borate, calcium chloride-sodium chloride are evenly mixed, put into a self-sealing bag and seal;

(4) In step (8), the reactor is heated to 750° C., calcium chloride-sodium chloride is melted to form molten salt, the CO2 is introduced for _2h , and the standing time is 3h; other methods are the same.

Example 44

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 41, except that:

(1) in step (1), calcium borate, calcium chloride, potassium chloride are dried to remove moisture;

(2) in step (4), under the protection of inert gas, weigh 38.0g ± 0.1g calcium chloride, take 6.3g ± 0.1g potassium chloride, grind evenly to obtain calcium chloride-potassium chloride;

(3) in step (5), the silicon-calcium alloy-calcium borate, calcium chloride-potassium chloride are mixed uniformly, put into ziplock bag and seal;

(4) In step (8), the reactor is heated to 670° C., calcium chloride-potassium chloride is melted to form molten salt, the CO2 is introduced for _2h , and the standing time is 3h; other methods are the same.

Example 45

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 41, except that:

(1) in step (1), calcium borate, calcium chloride, potassium chloride, sodium chloride are dried to remove moisture;

(2) In step (4), under the protection of inert gas, weigh 38.0g±0.1g calcium chloride, 3.2g±0.1g potassium chloride, 2.5g±0.1g sodium chloride, grind evenly, Obtain calcium chloride-potassium chloride-sodium chloride;

(3) in step (5), silicon-calcium alloy-calcium borate, calcium chloride-potassium chloride-sodium chloride are evenly mixed, put into a self-sealing bag and seal;

(4) Step (8) The reactor is heated to 630° C., calcium chloride-potassium chloride-sodium chloride is melted to form molten salt, the CO2 is introduced for _2h , and the standing time is 3h; other methods are the same.

Example 46

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 41, except that:

(1) in step (1), calcium borate, calcium chloride, sodium chloride, magnesium chloride are dried to remove moisture;

(2) In step (4), under the protection of inert gas, weigh 38.0g±0.1g calcium chloride, 28.0g±0.1g magnesium chloride, 5.0g±0.1g sodium chloride, grind evenly, and obtain chlorine calcium chloride-magnesium chloride-sodium chloride;

(3) in step (5), silicon-calcium alloy-calcium borate, calcium chloride-magnesium chloride-sodium chloride are evenly mixed, and packed into a self-sealing bag and sealed;

(4) In step (8), the reactor is heated to 620° C., calcium chloride-magnesium chloride-sodium chloride is melted to form molten salt, the CO2 is introduced for _2h , and the standing time is 3h; other methods are the same.

Example 47

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 41, except that:

(1) in step (1), calcium borate, calcium chloride, potassium chloride, magnesium chloride are dried to remove moisture;

(2) in step (4), under the protection of inert gas, weigh 38.0g ± 0.1g calcium chloride, weigh 28.0g ± 0.1g magnesium chloride, weigh 6.3g ± 0.1g potassium chloride, grind evenly to obtain calcium chloride-magnesium chloride-potassium chloride;

(3) in step (5), the silicon-calcium alloy-calcium borate, calcium chloride-magnesium chloride-potassium chloride are evenly mixed, put into a self-sealing bag and seal;

(4) In step (8), the reactor is heated to 590° C., calcium chloride-magnesium chloride-potassium chloride is melted to form molten salt, and the _CO2 time is 2h, and the standing time is 3h, wherein, the _CO2 The inflow flow is 200mL/min; other methods are the same.

Example 48

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 41, except that:

(1) in step (1), calcium borate, calcium chloride, potassium chloride, sodium chloride, magnesium chloride are dried to remove moisture;

(2) In step (4), under the protection of inert gas, weigh 38.0g±0.1g calcium chloride, 28.0g±0.1g magnesium chloride, 3.2g±0.1g potassium chloride, and 2.5g ±0.1g sodium chloride, ground evenly to obtain calcium chloride-magnesium chloride-potassium chloride-sodium chloride;

(3) in step (5), the silicon-calcium alloy-calcium borate, calcium chloride-magnesium chloride-potassium chloride-sodium chloride are evenly mixed, put into a self-sealing bag and sealed;

(4) In step (8), the reactor is heated to 530 ° C, calcium chloride-magnesium chloride-potassium chloride-sodium chloride is melted to form molten salt, the _CO2 time is 2h, and the standing time is 3h, wherein , the flow rate of CO ₂ is 100mL/min; other methods are the same.

Example 49

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 48, except that:

(1) In step (8), the reactor is heated to 530 ° C, calcium chloride-magnesium chloride-potassium chloride-sodium chloride is melted to form molten salt, the _CO2 time is 2h, and the standing time is 2h, wherein , the flow rate of CO ₂ is 100mL/min; other methods are the same.

Example 50

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 48, except that:

(1) In step (8), the reactor is heated to 530 ° C, calcium chloride-magnesium chloride-potassium chloride-sodium chloride is melted to form molten salt, the _CO2 time is 2h, and the standing time is 2h, wherein , the flow rate of CO ₂ is 100mL/min; other methods are the same.

Example 51

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 1, except that:

(1) in step (1), borax, calcium chloride are dried to remove moisture;

(2) In step (2), under the protection of inert gas, weigh 13.0g±0.1g of silicon-calcium alloy, weigh 4.5g±0.1g of borax, grind and mix to obtain silicon-calcium alloy-borax;

(2) in step (4), under the protection of inert gas, weigh 80.0g ± 0.1g calcium chloride, grind evenly to obtain calcium chloride;

(3) in step (5), the silicon-calcium alloy-borax and calcium chloride are mixed uniformly, packed into a self-sealing bag and sealed;

(4) In step (8), the reactor is heated to 800° C., calcium chloride is melted to form molten salt, the CO2 is introduced for _2h , and the standing time is 3h; other methods are the same.

Example 52

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 51, except that:

(1) in step (1), borax, calcium chloride, magnesium chloride are dried to remove moisture;

(2) in step (4), under the protection of inert gas, weigh 80.0g ± 0.1g calcium chloride, take 55.0g ± 0.1g magnesium chloride, grind evenly to obtain calcium chloride-magnesium chloride;

(3) in step (5), the silicon-calcium alloy-borax, calcium chloride-magnesium chloride are mixed uniformly, and packed into a self-sealing bag to seal;

(4) In step (8), the reactor is heated to 700° C., calcium chloride-magnesium chloride is melted to form molten salt, the CO2 is introduced for _2h , and the standing time is 3h; other methods are the same.

Example 53

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 51, except that:

(1) in step (1), borax, calcium chloride, sodium chloride are dried to remove moisture;

(2) in step (4), under the protection of inert gas, weigh 80.0g ± 0.1g calcium chloride, take 9.9g ± 0.1g sodium chloride, grind evenly to obtain calcium chloride-sodium chloride;

(3) in step (5), the silicon-calcium alloy-borax, calcium chloride-sodium chloride are mixed uniformly, and packed into a self-sealing bag to seal;

(4) In step (8), the reactor is heated to 750° C., calcium chloride-sodium chloride is melted to form molten salt, the CO2 is introduced for _2h , and the standing time is 3h; other methods are the same.

Example 54

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 51, except that:

(1) in step (1), borax, calcium chloride, potassium chloride are dried to remove moisture;

(2) in step (4), under the protection of inert gas, weigh 80.0g ± 0.1g calcium chloride, take 12.6g ± 0.1g potassium chloride, grind evenly to obtain calcium chloride-potassium chloride;

(3) in step (5), the silicon-calcium alloy-borax, calcium chloride-potassium chloride are evenly mixed, put into a self-sealing bag and seal;

(4) In step (8), the reactor is heated to 670° C., calcium chloride-potassium chloride is melted to form molten salt, the CO2 is introduced for _2h , and the standing time is 3h; other methods are the same.

Example 55

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 51, except that:

(1) in step (1), borax, calcium chloride, potassium chloride, sodium chloride are dried to remove moisture;

(2) In step (4), under the protection of inert gas, weigh 80.0g±0.1g calcium chloride, 6.3g±0.1g potassium chloride, 5.0g±0.1g sodium chloride, and grind them evenly, Obtain calcium chloride-potassium chloride-sodium chloride;

(3) in step (5), silicon-calcium alloy-borax, calcium chloride-potassium chloride-sodium chloride are evenly mixed, put into a self-sealing bag and seal;

(4) Step (8) The reactor is heated to 630° C., calcium chloride-potassium chloride-sodium chloride is melted to form molten salt, the CO2 is introduced for _2h , and the standing time is 3h; other methods are the same.

Example 56

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 51, except that:

(1) in step (1), borax, calcium chloride, sodium chloride, magnesium chloride are dried to remove moisture;

(2) In step (4), under the protection of inert gas, weigh 80.0g±0.1g calcium chloride, 55.0g±0.1g magnesium chloride, 9.9g±0.1g sodium chloride, grind evenly to obtain chlorine calcium chloride-magnesium chloride-sodium chloride;

(3) in step (5), silicon-calcium alloy-borax, calcium chloride-magnesium chloride-sodium chloride are evenly mixed, and packed into a self-sealing bag to seal;

(4) In step (8), the reactor is heated to 620° C., calcium chloride-magnesium chloride-sodium chloride is melted to form molten salt, the CO2 is introduced for _2h , and the standing time is 3h; other methods are the same.

Example 57

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 51, except that:

(1) in step (1), borax, calcium chloride, potassium chloride, magnesium chloride are dried to remove moisture;

(2) In step (4), under the protection of inert gas, weigh 80.0g±0.1g calcium chloride, 55.0g±0.1g magnesium chloride, 12.6g±0.1g potassium chloride, grind evenly, and obtain calcium chloride-magnesium chloride-potassium chloride;

(3) in step (5), the silicon-calcium alloy-borax, calcium chloride-magnesium chloride-potassium chloride are mixed uniformly, and packed into a self-sealing bag to seal;

(4) In step (8), the reactor is heated to 590° C., calcium chloride-magnesium chloride-potassium chloride is melted to form molten salt, and the _CO2 time is 2h, and the standing time is 3h, wherein, the _CO2 The inflow flow is 200mL/min; other methods are the same.

Example 58

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 51, except that:

(1) in step (1), borax, calcium chloride, potassium chloride, sodium chloride, magnesium chloride are dried to remove moisture;

(2) In step (4), under the protection of inert gas, weigh 80.0g±0.1g calcium chloride, 55.0g±0.1g magnesium chloride, 6.3g±0.1g potassium chloride, 5.0g±0.1g sodium chloride , grind evenly to obtain calcium chloride-magnesium chloride-potassium chloride-sodium chloride;

(3) in step (5), the silicon-calcium alloy-borax, calcium chloride-magnesium chloride-potassium chloride-sodium chloride are mixed uniformly, and packed into a self-sealing bag to seal;

(4) In step (8), the reactor is heated to 530 ° C, calcium chloride-magnesium chloride-potassium chloride-sodium chloride is melted to form molten salt, the _CO2 time is 2h, and the standing time is 3h, wherein , the flow rate of CO ₂ is 100mL/min; other methods are the same.

Example 59

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 58, except that:

(1) In step (8), the reactor is heated to 530 ° C, calcium chloride-magnesium chloride-potassium chloride-sodium chloride is melted to form molten salt, the _CO2 time is 2h, and the standing time is 2h, wherein , the flow rate of CO ₂ is 200mL/min; other methods are the same.

Example 60

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 58, except that:

(1) In step (8), the reactor is heated to 530 ° C, calcium chloride-magnesium chloride-potassium chloride-sodium chloride is melted to form molten salt, the _CO2 time is 2h, and the standing time is 2h, wherein , the flow rate of CO ₂ is 100mL/min; other methods are the same.

Example 61

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is carried out according to the following steps:

(1) dry boron oxide and calcium chloride to remove moisture;

(2) Under the protection of inert gas, weigh 6.5g±0.1g of silicon-calcium alloy, weigh 1.5g±0.1g of boron oxide, grind and mix to obtain silicon-calcium alloy-boron oxide;

(3) Under the protection of inert gas, weigh 75.0g±0.1g calcium chloride, and grind it evenly;

(4) uniformly mixing silicon-calcium alloy-boron oxide and calcium chloride to obtain the mixed salt, which is sealed in a ziplock bag;

(5) Put the mixed salt into the crucible embedded in the reactor, and seal the reactor lid.

(6) feed inert gas from the air inlet of the reactor cover, discharge the inert gas from the air outlet of the reactor cover, and ensure that the reactor is positive pressure;

(7) The resistance wire furnace is heated up, and the heating rate is 10°C/min;

(8) The reactor was heated to 800°C, calcium chloride was melted to form molten salt, kept warm, inserted a stirring paddle, and at the same time, CO ₂ was introduced into the molten salt from another air inlet of the reactor cover, ventilated for 2 hours, and the ventilated At the same time, the stirring paddle was rotated, and the stirring speed was 700 r/min. After the ventilation was completed, the stirring was continued for 3 hours to obtain the reacted product;

(9) heating up the salt pipe;

(10) After the salt in the salt outlet pipe is melted, the reacted product flows out from the salt outlet and is stored in a stainless steel container for cooling.

(11) a small amount of reacted product remains in the salt outlet pipe, stop heating the salt outlet pipe, and the residual reacted product is cooled and automatically seals the salt outlet;

(12) The resistance wire furnace is cooled to room temperature, and the inert gas is stopped;

(13) Take out the cooled salt from the stainless steel container and grind it; wash off the salt with 0.1mol/L hydrochloric acid, filter; wash the filtered product with deionized water; vacuum dry at 70° C. to obtain a silicon-based Si-B-C negative electrode material , sealed for use;

(14) The prepared silicon-based Si-B-C negative electrode material is made into a lithium ion battery negative electrode, and an electrochemical test is performed.

Example 62

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 61, except that:

(1) in the molten salt reaction process of step (8), the time of introducing _CO is 1.5h, and after the ventilation is completed, stirring is continued for 3h;

The other way is the same.

Example 63

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 61, except that:

(1) in the molten salt reaction process of step (8), the time of introducing _CO is 1h, and after the ventilation is completed, stirring is continued for 3h;

The other way is the same.

Example 64

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 61, except that:

(1) in the molten salt reaction process of step (8), the time of introducing _CO is 1h, and after the ventilation is completed, stirring is continued for 2h;

The other way is the same.

Example 65

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 61, except that:

(1) in the molten salt reaction process of step (8), the time of introducing _CO is 1h, and after the ventilation is completed, stirring is continued for 1h;

The other way is the same.

Example 66

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 61, except that:

(1) in step (1), dry boron oxide, calcium chloride, magnesium chloride to remove moisture;

(2) in step (4), under the protection of inert gas, weigh 75.0g ± 0.1g calcium chloride, take 55.0g ± 0.1g magnesium chloride, grind evenly to obtain calcium chloride-magnesium chloride;

(3) in step (5), the silicon-calcium alloy-boron oxide, calcium chloride-magnesium chloride are mixed uniformly, and packed into a self-sealing bag to seal;

(4) In step (8), the reactor was heated to 700° C., calcium chloride-magnesium chloride was melted to form molten salt, and CO was introduced for ₂ hours. After the aeration was completed, stirring was continued for 3 hours; other methods were the same.

Example 67

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 61, except that:

(1) in step (1), dry boron oxide, calcium chloride, sodium chloride to remove moisture;

(2) in step (4), under the protection of inert gas, weigh 75.0g ± 0.1g calcium chloride, take 9.9g ± 0.1g sodium chloride, grind evenly to obtain calcium chloride-sodium chloride;

(3) in step (5), the silicon-calcium alloy-boron oxide, calcium chloride-sodium chloride are mixed uniformly, and packed into a self-sealing bag to seal;

(4) In step (8), the reactor was heated to 750° C., calcium chloride-sodium chloride was melted to form molten salt, CO was introduced for ₂ hours, and after the ventilation was completed, stirring was continued for 3 hours; other methods were the same.

Example 68

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 61, except that:

(1) in step (1), dry and remove moisture by boron oxide, calcium chloride, potassium chloride;

(2) in step (4), under the protection of inert gas, weigh 75.0g ± 0.1g calcium chloride, take 12.6g ± 0.1g potassium chloride, grind evenly to obtain calcium chloride-potassium chloride;

(3) in step (5), the silicon-calcium alloy-boron oxide, calcium chloride-potassium chloride are mixed uniformly, put into ziplock bag and seal;

(4) In step (8), the reactor was heated to 670° C., calcium chloride-potassium chloride was melted to form molten salt, and CO was introduced for ₂ hours. After the aeration was completed, stirring was continued for 3 hours; other methods were the same.

Example 69

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 61, except that:

(1) in step (1), dry and remove moisture by boron oxide, calcium chloride, potassium chloride, sodium chloride;

(2) In step (4), under the protection of inert gas, weigh 75.0g±0.1g calcium chloride, 6.3g±0.1g potassium chloride, 5.0g±0.1g sodium chloride, and grind them evenly , obtain calcium chloride-potassium chloride-sodium chloride;

(3) in step (5), the silicon-calcium alloy-boron oxide, calcium chloride-potassium chloride-sodium chloride are mixed uniformly, and packed into a self-sealing bag to seal;

(4) In step (8), the reactor is heated to 630°C, calcium chloride-potassium chloride-sodium chloride is melted to form molten salt, and CO is introduced for _2h , and after the ventilation is completed, stirring is continued for 3h; The other way is the same.

Example 70

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 61, except that:

(1) in step (1), dry the boron oxide, calcium chloride, sodium chloride, magnesium chloride to remove moisture;

(2) In step (4), under the protection of inert gas, weigh 75.0g±0.1g calcium chloride, 55.0g±0.1g magnesium chloride, 9.9g±0.1g sodium chloride, grind evenly, and obtain calcium chloride-magnesium chloride-sodium chloride;

(3) in step (5), the silicon-calcium alloy-boron oxide, calcium chloride-magnesium chloride-sodium chloride are mixed uniformly, and packed into a self-sealing bag to seal;

(4) In step (8), the reactor is heated to 620°C, the calcium chloride-magnesium chloride-sodium chloride is melted to form molten salt, the _CO2 is introduced for 2h, and after the ventilation is completed, stirring is continued for 3h; other methods same.

Example 71

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 61, except that:

(1) in step (1), dry and remove moisture by boron oxide, calcium chloride, potassium chloride, magnesium chloride;

(2) In step (4), under the protection of inert gas, weigh 75.0g±0.1g calcium chloride, 55.0g±0.1g magnesium chloride, 12.6g±0.1g potassium chloride, grind evenly, and obtain calcium chloride-magnesium chloride-potassium chloride;

(3) in step (5), the silicon-calcium alloy-boron oxide, calcium chloride-magnesium chloride-potassium chloride are evenly mixed, put into a self-sealing bag and seal;

(4) In step (8), the reactor is heated to 590° C., calcium chloride-magnesium chloride-potassium chloride is melted to form molten salt, and CO is introduced for _2h . After the ventilation is completed, stirring is continued for 3h; other methods same.

Example 72

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 61, except that:

(1) in step (1), dry and remove moisture by boron oxide, calcium chloride, potassium chloride, sodium chloride, magnesium chloride;

(2) In step (4), under the protection of inert gas, weigh 75.0g±0.1g calcium chloride, 55.0g±0.1g magnesium chloride, 6.3g±0.1g potassium chloride, 5.0g±0.1g sodium chloride , grind evenly to obtain calcium chloride-magnesium chloride-potassium chloride-sodium chloride;

(3) in step (5), the silicon-calcium alloy-boron oxide, calcium chloride-magnesium chloride-potassium chloride-sodium chloride are mixed uniformly, and packed into a self-sealing bag to seal;

(4) In step (8), the reactor is heated to 530 ° C, calcium chloride-magnesium chloride-potassium chloride-sodium chloride is melted to form molten salt, and CO is introduced for _2h , and after the ventilation is completed, continue stirring 3h; otherwise the same.

Example 73

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 61, except that:

(1) In step (8), in the molten salt reaction process, _CO2 was introduced for 2h, and the stirring speed was 650r/min. After the ventilation was completed, the stirring was continued for 4h; other methods were the same.

Example 74

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 61, except that:

(1) In step (8), in the molten salt reaction process, _CO2 was introduced for a time of 2h, and the stirring speed was 600r/min. After the ventilation was completed, the stirring was continued for 3h; other methods were the same.

Example 75

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 61, except that:

(1) In step (8), in the molten salt reaction process, _CO2 was introduced for 1.5h, and the stirring speed was 450r/min. After the ventilation was completed, stirring was continued for 3h; other methods were the same.

Example 76

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 61, except that:

(1) In step (8), in the molten salt reaction process, _CO2 was introduced for 1 h, and the stirring speed was 400 r/min. After the ventilation was completed, the stirring was continued for 3 h; other methods were the same.

Example 77

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 61, except that:

(1) In step (8), during the molten salt reaction process, _CO2 was introduced for 1 h, and the stirring speed was 200 r/min. After the ventilation was completed, the stirring was continued for 2 h; other methods were the same.

Example 78

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 61, except that:

(1) in step (1), calcium borate, calcium chloride are dried to remove moisture;

(2) in step (2), under the protection of inert gas, weigh 6.5g ± 0.1g of calcium-silicon alloy, weigh 2.83g ± 0.1g of calcium borate, grind and mix to obtain calcium-silicon alloy-calcium borate;

(3) in step (5), the silicon-calcium alloy-calcium borate and calcium chloride are mixed uniformly, packed into a self-sealing bag and sealed;

(4) In step (8), the reactor is heated to 800° C., and the calcium chloride is melted to form molten salt; other methods are the same.

Example 79

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 78, except that:

(1) in step (1), calcium borate, calcium chloride, magnesium chloride are dried to remove moisture;

(2) in step (4), under the protection of inert gas, weigh 38.0g ± 0.1g calcium chloride, take 28.0g ± 0.1g magnesium chloride, grind evenly to obtain calcium chloride-magnesium chloride;

(3) in step (5), the silicon-calcium alloy-calcium borate, calcium chloride-magnesium chloride are mixed uniformly, put into ziplock bag to seal;

(4) In step (8), the reactor is heated to 700° C., and calcium chloride-magnesium chloride is melted to form molten salt; other methods are the same.

Example 80

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 78, except that:

(1) in step (1), calcium borate, calcium chloride, sodium chloride are dried to remove moisture;

(2) in step (4), under inert gas protection, weigh 38.0g ± 0.1g calcium chloride, take 5.0g ± 0.1g sodium chloride, grind evenly to obtain calcium chloride-sodium chloride;

(3) in step (5), the silicon-calcium alloy-calcium borate, calcium chloride-sodium chloride are evenly mixed, put into a self-sealing bag and seal;

(4) In step (8), the reactor is heated to 750° C., and calcium chloride-sodium chloride is melted to form molten salt; other methods are the same.

Example 81

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 78, except that:

(1) in step (1), calcium borate, calcium chloride, potassium chloride are dried to remove moisture;

(2) in step (4), under the protection of inert gas, weigh 38.0g ± 0.1g calcium chloride, take 6.3g ± 0.1g potassium chloride, grind evenly to obtain calcium chloride-potassium chloride;

(3) in step (5), the silicon-calcium alloy-calcium borate, calcium chloride-potassium chloride are mixed uniformly, put into ziplock bag and seal;

(4) In step (8), the reactor is heated to 670° C., calcium chloride-potassium chloride is melted to form molten salt; other methods are the same.

Example 82

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 78, except that:

(1) in step (1), calcium borate, calcium chloride, potassium chloride, sodium chloride are dried to remove moisture;

(2) In step (4), under the protection of inert gas, weigh 38.0g±0.1g calcium chloride, 3.2g±0.1g potassium chloride, 2.5g±0.1g sodium chloride, grind evenly, Obtain calcium chloride-potassium chloride-sodium chloride;

(3) in step (5), silicon-calcium alloy-calcium borate, calcium chloride-potassium chloride-sodium chloride are evenly mixed, put into a self-sealing bag and seal;

(4) In step (8), the reactor is heated to 630° C., and calcium chloride-potassium chloride-sodium chloride is melted to form molten salt; other methods are the same.

Example 83

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 78, except that:

(1) in step (1), calcium borate, calcium chloride, sodium chloride, magnesium chloride are dried to remove moisture;

(2) In step (4), under the protection of inert gas, weigh 38.0g±0.1g calcium chloride, 28.0g±0.1g magnesium chloride, 5.0g±0.1g sodium chloride, grind evenly, and obtain chlorine calcium chloride-magnesium chloride-sodium chloride;

(3) in step (5), silicon-calcium alloy-calcium borate, calcium chloride-magnesium chloride-sodium chloride are evenly mixed, and packed into a self-sealing bag and sealed;

(4) In step (8), the reactor is heated to 620° C., and calcium chloride-magnesium chloride-sodium chloride is melted to form molten salt; other methods are the same.

Example 84

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 78, except that:

(1) in step (1), calcium borate, calcium chloride, potassium chloride, magnesium chloride are dried to remove moisture;

(2) in step (4), under the protection of inert gas, weigh 38.0g ± 0.1g calcium chloride, weigh 28.0g ± 0.1g magnesium chloride, weigh 6.3g ± 0.1g potassium chloride, grind evenly to obtain calcium chloride-magnesium chloride-potassium chloride;

(3) in step (5), the silicon-calcium alloy-calcium borate, calcium chloride-magnesium chloride-potassium chloride are evenly mixed, put into a self-sealing bag and seal;

(4) in step (8), the reactor is heated to 590 ℃, and calcium chloride-magnesium chloride-potassium chloride is melted to form molten salt;

The other way is the same.

Example 85

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 78, except that:

(1) in step (1), calcium borate, calcium chloride, potassium chloride, sodium chloride, magnesium chloride are dried to remove moisture;

(2) In step (4), under the protection of inert gas, weigh 38.0g±0.1g calcium chloride, 28.0g±0.1g magnesium chloride, 3.2g±0.1g potassium chloride, 2.5g±0.1g sodium chloride, Grind evenly to obtain calcium chloride-magnesium chloride-potassium chloride-sodium chloride;

(3) in step (5), the silicon-calcium alloy-calcium borate, calcium chloride-magnesium chloride-potassium chloride-sodium chloride are evenly mixed, put into a self-sealing bag and sealed;

(4) in step (8), the reactor is heated to 530 ℃, and calcium chloride-magnesium chloride-potassium chloride-sodium chloride is melted to form molten salt;

The other way is the same.

Example 86

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 85, except that:

(1) In step (8), the reactor is heated to 530 ° C, calcium chloride-magnesium chloride-potassium chloride-sodium chloride is melted to form molten salt, the _CO2 time is 2h, and the standing time is 2h, wherein , the flow rate of CO ₂ is 200mL/min; other methods are the same.

Example 87

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 85, except that:

(1) In step (8), the reactor is heated to 530 ° C, calcium chloride-magnesium chloride-potassium chloride-sodium chloride is melted to form molten salt, the _CO2 time is 2h, and the standing time is 2h, wherein , the flow rate of CO ₂ is 100mL/min; other methods are the same.

Example 88

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 61, except that:

(1) in step (1), borax, calcium chloride are dried to remove moisture;

(2) In step (2), under the protection of inert gas, weigh 13.0g±0.1g of silicon-calcium alloy, weigh 4.5g±0.1g of borax, grind and mix to obtain silicon-calcium alloy-borax;

(2) in step (4), under the protection of inert gas, weigh 80.0g ± 0.1g calcium chloride, grind evenly to obtain calcium chloride;

(3) in step (5), the silicon-calcium alloy-borax and calcium chloride are mixed uniformly, packed into a self-sealing bag and sealed;

(4) In step (8), the reactor is heated to 800° C., and the calcium chloride is melted to form molten salt; other methods are the same.

Example 89

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 88, except that:

(1) in step (1), borax, calcium chloride, magnesium chloride are dried to remove moisture;

(2) in step (4), under the protection of inert gas, weigh 80.0g ± 0.1g calcium chloride, take 55.0g ± 0.1g magnesium chloride, grind evenly to obtain calcium chloride-magnesium chloride;

(3) in step (5), the silicon-calcium alloy-borax, calcium chloride-magnesium chloride are mixed uniformly, and packed into a self-sealing bag to seal;

(4) In step (8), the reactor is heated to 700° C., and calcium chloride-magnesium chloride is melted to form molten salt; other methods are the same.

Example 90

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 88, except that:

(1) in step (1), borax, calcium chloride, sodium chloride are dried to remove moisture;

(2) in step (4), under the protection of inert gas, weigh 80.0g ± 0.1g calcium chloride, take 9.9g ± 0.1g sodium chloride, grind evenly to obtain calcium chloride-sodium chloride;

(3) in step (5), the silicon-calcium alloy-borax, calcium chloride-sodium chloride are mixed uniformly, packed into a self-sealing bag and sealed;

(4) In step (8), the reactor is heated to 750° C., and calcium chloride-sodium chloride is melted to form molten salt; other methods are the same.

Example 91

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 88, except that:

(1) in step (1), borax, calcium chloride, potassium chloride are dried to remove moisture;

(2) in step (4), under the protection of inert gas, weigh 80.0g ± 0.1g calcium chloride, take 12.6g ± 0.1g potassium chloride, grind evenly to obtain calcium chloride-potassium chloride;

(3) in step (5), the silicon-calcium alloy-borax, calcium chloride-potassium chloride are evenly mixed, put into a self-sealing bag and seal;

(4) In step (8), the reactor is heated to 670° C., calcium chloride-potassium chloride is melted to form molten salt; other methods are the same.

Example 92

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 88, except that:

(1) in step (1), borax, calcium chloride, potassium chloride, sodium chloride are dried to remove moisture;

(2) In step (4), under the protection of inert gas, weigh 80.0g±0.1g calcium chloride, 6.3g±0.1g potassium chloride, 5.0g±0.1g sodium chloride, and grind them evenly, Obtain calcium chloride-potassium chloride-sodium chloride;

(3) in step (5), silicon-calcium alloy-borax, calcium chloride-potassium chloride-sodium chloride are evenly mixed, put into a self-sealing bag and seal;

(4) In step (8), the reactor is heated to 630° C., calcium chloride-potassium chloride-sodium chloride is melted to form molten salt; other methods are the same.

Example 93

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 88, except that:

(1) in step (1), borax, calcium chloride, sodium chloride, magnesium chloride are dried to remove moisture;

(2) In step (4), under the protection of inert gas, weigh 80.0g±0.1g calcium chloride, 55.0g±0.1g magnesium chloride, 9.9g±0.1g sodium chloride, grind evenly to obtain chlorine calcium chloride-magnesium chloride-sodium chloride;

(3) in step (5), silicon-calcium alloy-borax, calcium chloride-magnesium chloride-sodium chloride are evenly mixed, and packed into a self-sealing bag to seal;

(4) In step (8), the reactor is heated to 620° C., and calcium chloride-magnesium chloride-sodium chloride is melted to form molten salt; other methods are the same.

Example 94

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 88, except that:

(1) in step (1), borax, calcium chloride, potassium chloride, magnesium chloride are dried to remove moisture;

(2) In step (4), under the protection of inert gas, weigh 80.0g±0.1g calcium chloride, 55.0g±0.1g magnesium chloride, 12.6g±0.1g potassium chloride, grind evenly, and obtain calcium chloride-magnesium chloride-potassium chloride;

(3) in step (5), the silicon-calcium alloy-borax, calcium chloride-magnesium chloride-potassium chloride are mixed uniformly, and packed into a self-sealing bag to seal;

(4) in step (8), the reactor is heated to 590 ℃, and calcium chloride-magnesium chloride-potassium chloride is melted to form molten salt;

The other way is the same.

Example 95

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 88, except that:

(1) in step (1), borax, calcium chloride, potassium chloride, sodium chloride, magnesium chloride are dried to remove moisture;

(2) In step (4), under the protection of inert gas, weigh 80.0g±0.1g calcium chloride, 55.0g±0.1g magnesium chloride, 6.3g±0.1g potassium chloride, 5.0g±0.1g sodium chloride , grind evenly to obtain calcium chloride-magnesium chloride-potassium chloride-sodium chloride;

(3) in step (5), the silicon-calcium alloy-borax, calcium chloride-magnesium chloride-potassium chloride-sodium chloride are mixed uniformly, and packed into a self-sealing bag to seal;

(4) in step (8), the reactor is heated to 530 ℃, and calcium chloride-magnesium chloride-potassium chloride-sodium chloride is melted to form molten salt;

The other way is the same.

Example 96

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 95, except that:

(1) In step (8), the reactor is heated to 530 ° C, calcium chloride-magnesium chloride-potassium chloride-sodium chloride is melted to form molten salt, the _CO2 time is 2h, and the standing time is 2h, wherein , the flow rate of CO ₂ is 200mL/min; other methods are the same.

Example 97

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 96, except that:

(1) In step (8), the reactor is heated to 530 ° C, calcium chloride-magnesium chloride-potassium chloride-sodium chloride is melted to form molten salt, the _CO2 time is 2h, and the standing time is 2h, wherein , the flow rate of CO ₂ is 100mL/min; other methods are the same.

Example 98

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 61, except that:

(1) in step (8), pass into the molten salt from another gas inlet of the reactor cover CO ₂ and the mixed gas of Ar, ventilate 2h, the flow velocity of passing gas is 400mL/min; Wherein, CO ₂ In the mixed gas with Ar, the volume ratio of CO ₂ and Ar is 1:1;

The other way is the same.

Example 99

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 61, except that:

(1) in step (1), magnesium borate, calcium chloride are dried to remove moisture;

(2) in step (2), under the protection of inert gas, weigh 6.5g±0.1g silicon-calcium alloy, weigh 3.4g±0.1g magnesium borate, grind and mix to obtain silicon-calcium alloy-magnesium borate;

(3) in step (3), under the protection of inert gas, take by weighing 25.0g ± 0.1g calcium chloride, grind evenly;

(4) in step (5), the silicon-calcium alloy-magnesium borate and calcium chloride are mixed uniformly, and packed into a self-sealing bag to seal;

(5) In step (8), the reactor is heated to 800° C., and the calcium chloride is melted to form molten salt; other methods are the same.

Example 100

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 99, except that:

(1) in step (1), magnesium borate, calcium chloride, magnesium chloride are dried to remove moisture;

(2) in step (4), under the protection of inert gas, weigh 25.0g ± 0.1g calcium chloride, take 18.7g ± 0.1g magnesium chloride, grind evenly to obtain calcium chloride-magnesium chloride;

(3) in step (5), the silicon-calcium alloy-magnesium borate, calcium chloride-magnesium chloride are evenly mixed, put into a self-sealing bag to seal;

(4) In step (8), the reactor is heated to 700° C., and calcium chloride-magnesium chloride is melted to form molten salt; other methods are the same.

Example 101

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 99, except that:

(1) in step (1), magnesium borate, calcium chloride, sodium chloride are dried to remove moisture;

(2) in step (4), under the protection of inert gas, weigh 25.0g ± 0.1g calcium chloride, take 3.3g ± 0.1g sodium chloride, grind evenly to obtain calcium chloride-sodium chloride;

(3) in step (5), the silicon-calcium alloy-magnesium borate, calcium chloride-sodium chloride are mixed uniformly, put into ziplock bag and seal;

(4) In step (8), the reactor is heated to 750° C., and calcium chloride-sodium chloride is melted to form molten salt; other methods are the same.

Example 102

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 99, except that:

(1) in step (1), magnesium borate, calcium chloride, potassium chloride are dried to remove moisture;

(2) in step (4), under the protection of inert gas, weigh 25.0g ± 0.1g calcium chloride, take 4.2g ± 0.1g potassium chloride, grind evenly to obtain calcium chloride-potassium chloride;

(3) in step (5), the silicon-calcium alloy-magnesium borate, calcium chloride-potassium chloride are mixed uniformly, put into ziplock bag and seal;

(4) In step (8), the reactor is heated to 670° C., calcium chloride-potassium chloride is melted to form molten salt; other methods are the same.

Example 103

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 99, except that:

(1) in step (1), magnesium borate, calcium chloride, potassium chloride, sodium chloride are dried to remove moisture;

(2) In step (4), under the protection of inert gas, weigh 25.0g±0.1g calcium chloride, 2.1g±0.1g potassium chloride, 1.7g±0.1g sodium chloride, grind evenly, Obtain calcium chloride-potassium chloride-sodium chloride;

(3) in step (5), silicon-calcium alloy-magnesium borate, calcium chloride-potassium chloride-sodium chloride are evenly mixed, put into ziplock bag and seal;

(4) In step (8), the reactor is heated to 630° C., and calcium chloride-potassium chloride-sodium chloride is melted to form molten salt; other methods are the same.

Example 104

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 99, except that:

(1) in step (1), magnesium borate, calcium chloride, sodium chloride, magnesium chloride are dried to remove moisture;

(2) In step (4), under the protection of inert gas, weigh 25.0g±0.1g calcium chloride, 18.7g±0.1g magnesium chloride, 3.3g±0.1g sodium chloride, grind evenly, and obtain chlorine calcium chloride-magnesium chloride-sodium chloride;

(3) in step (5), silicon-calcium alloy-magnesium borate, calcium chloride-magnesium chloride-sodium chloride are evenly mixed, put into a self-sealing bag and seal;

(4) In step (8), the reactor is heated to 620° C., and calcium chloride-magnesium chloride-sodium chloride is melted to form molten salt; other methods are the same.

Example 105

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 99, except that:

(1) in step (1), magnesium borate, calcium chloride, potassium chloride, magnesium chloride are dried to remove moisture;

(2) In step (4), under the protection of inert gas, weigh 25.0g±0.1g calcium chloride, 18.7g±0.1g magnesium chloride, 4.2g±0.1g potassium chloride, grind evenly, and obtain calcium chloride-magnesium chloride-potassium chloride;

(3) in step (5), the silicon-calcium alloy-magnesium borate, calcium chloride-magnesium chloride-potassium chloride are mixed uniformly, put into ziplock bag and seal;

(4) in step (8), the reactor is heated to 590 ℃, and calcium chloride-magnesium chloride-potassium chloride is melted to form molten salt;

The other way is the same.

Example 106

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 99, except that:

(1) in step (1), magnesium borate, calcium chloride, potassium chloride, sodium chloride, magnesium chloride are dried to remove moisture;

(2) In step (4), under the protection of inert gas, weigh 25.0g±0.1g calcium chloride, 18.7g±0.1g magnesium chloride, 2.1g±0.1g potassium chloride, and 1.7g±0.1g sodium chloride , grind evenly to obtain calcium chloride-magnesium chloride-potassium chloride-sodium chloride;

(3) In step (5), the calcium-silicon alloy-magnesium borate, calcium chloride-magnesium chloride-potassium chloride-sodium chloride are mixed uniformly, and packed into a self-sealing bag to seal;

(4) in step (8), the reactor is heated to 530 ℃, and calcium chloride-magnesium chloride-potassium chloride-sodium chloride is melted to form molten salt;

The other way is the same.

Example 107

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 106, except that:

(1) In step (8), the reactor is heated to 530 ° C, calcium chloride-magnesium chloride-potassium chloride-sodium chloride is melted to form molten salt, the _CO2 time is 2h, and the standing time is 2h, wherein , the flow rate of CO ₂ is 200mL/min; other methods are the same.

Example 108

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 106, except that:

(1) In step (8), the reactor is heated to 530 ° C, calcium chloride-magnesium chloride-potassium chloride-sodium chloride is melted to form molten salt, the _CO2 time is 2h, and the standing time is 2h, wherein , the flow rate of CO ₂ is 100mL/min; other methods are the same.

Example 109

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 61, except that:

(1) in step (1), potassium borate, calcium chloride are dried to remove moisture;

(2) In step (2), under the protection of inert gas, weigh 13.0g±0.1g of silicon-calcium alloy, weigh 5.3g±0.1g of potassium borate, grind and mix to obtain silicon-calcium alloy-potassium borate;

(2) in step (4), under the protection of inert gas, weigh 75.0g ± 0.1g calcium chloride, grind evenly to obtain calcium chloride;

(3) in step (5), the silicon-calcium alloy-potassium borate and calcium chloride are mixed uniformly, and packed into a self-sealing bag to seal;

(4) In step (8), the reactor is heated to 800° C., and the calcium chloride is melted to form molten salt; other methods are the same.

Example 110

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 109, except that:

(1) in step (1), potassium borate, calcium chloride, magnesium chloride are dried to remove moisture;

(2) in step (4), under the protection of inert gas, weigh 80.0g ± 0.1g calcium chloride, take 55.0g ± 0.1g magnesium chloride, grind evenly to obtain calcium chloride-magnesium chloride;

(3) in step (5), the silicon-calcium alloy-potassium borate, calcium chloride-magnesium chloride are mixed uniformly, put into ziplock bag and seal;

(4) In step (8), the reactor is heated to 700° C., and calcium chloride-magnesium chloride is melted to form molten salt; other methods are the same.

Example 111

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 109, except that:

(1) in step (1), potassium borate, calcium chloride, sodium chloride are dried to remove moisture;

(2) in step (4), under the protection of inert gas, weigh 80.0g ± 0.1g calcium chloride, take 9.9g ± 0.1g sodium chloride, grind evenly to obtain calcium chloride-sodium chloride;

(3) in step (5), the silicon-calcium alloy-potassium borate, calcium chloride-sodium chloride are mixed uniformly, put into ziplock bag and seal;

(4) In step (8), the reactor is heated to 750° C., and calcium chloride-sodium chloride is melted to form molten salt; other methods are the same.

Example 112

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 109, except that:

(1) in step (1), potassium borate, calcium chloride, potassium chloride are dried to remove moisture;

(2) in step (4), under the protection of inert gas, weigh 80.0g ± 0.1g calcium chloride, take 12.6g ± 0.1g potassium chloride, grind evenly to obtain calcium chloride-potassium chloride;

(3) in step (5), the silicon-calcium alloy-potassium borate, calcium chloride-potassium chloride are evenly mixed, put into a self-sealing bag and seal;

(4) In step (8), the reactor is heated to 670° C., calcium chloride-potassium chloride is melted to form molten salt; other methods are the same.

Example 113

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 109, except that:

(1) in step (1), potassium borate, calcium chloride, potassium chloride, sodium chloride are dried to remove moisture;

(2) In step (4), under the protection of inert gas, weigh 80.0g±0.1g calcium chloride, 6.3g±0.1g potassium chloride, 5.0g±0.1g sodium chloride, and grind them evenly, Obtain calcium chloride-potassium chloride-sodium chloride;

(3) in step (5), silicon-calcium alloy-potassium borate, calcium chloride-potassium chloride-sodium chloride are evenly mixed, put into a self-sealing bag and seal;

(4) In step (8), the reactor is heated to 630° C., calcium chloride-potassium chloride-sodium chloride is melted to form molten salt; other methods are the same.

Example 114

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 109, except that:

(1) in step (1), potassium borate, calcium chloride, sodium chloride, magnesium chloride are dried to remove moisture;

(2) In step (4), under the protection of inert gas, weigh 80.0g±0.1g calcium chloride, 55.0g±0.1g magnesium chloride, 9.9g±0.1g sodium chloride, grind evenly to obtain chlorine calcium chloride-magnesium chloride-sodium chloride;

(3) in step (5), silicon-calcium alloy-potassium borate, calcium chloride-magnesium chloride-sodium chloride are evenly mixed, put into a self-sealing bag and seal;

(4) In step (8), the reactor is heated to 620° C., and calcium chloride-magnesium chloride-sodium chloride is melted to form molten salt; other methods are the same.

Example 115

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 109, except that:

(1) in step (1), potassium borate, calcium chloride, potassium chloride, magnesium chloride are dried to remove moisture;

(2) In step (4), under the protection of inert gas, weigh 80.0g±0.1g calcium chloride, 55.0g±0.1g magnesium chloride, 12.6g±0.1g potassium chloride, grind evenly, and obtain calcium chloride-magnesium chloride-potassium chloride;

(3) in step (5), the silicon-calcium alloy-potassium borate, calcium chloride-magnesium chloride-potassium chloride are mixed uniformly, packed into ziplock bag and sealed;

(4) in step (8), the reactor is heated to 590 ℃, and calcium chloride-magnesium chloride-potassium chloride is melted to form molten salt;

The other way is the same.

Example 116

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 109, except that:

(1) in step (1), potassium borate, calcium chloride, potassium chloride, sodium chloride, magnesium chloride are dried to remove moisture;

(2) In step (4), under the protection of inert gas, weigh 80.0g±0.1g calcium chloride, 55.0g±0.1g magnesium chloride, 6.3g±0.1g potassium chloride, 5.0g±0.1g sodium chloride , grind evenly to obtain calcium chloride-magnesium chloride-potassium chloride-sodium chloride;

(3) In step (5), the calcium-silicon alloy-potassium borate, calcium chloride-magnesium chloride-potassium chloride-sodium chloride are mixed uniformly, and packed into a self-sealing bag and sealed;

(4) in step (8), the reactor is heated to 530 ℃, and calcium chloride-magnesium chloride-potassium chloride-sodium chloride is melted to form molten salt;

The other way is the same.

Example 117

A preparation method of a silicon-based Si-BC negative electrode material prepared based on CO ₂ is the same as in Example 61, except that:

(1) in step (8), pass into the molten salt from another gas inlet of the reactor cover CO ₂ and the mixed gas of Ar, ventilate 2h, the flow velocity of passing gas is 400mL/min; Wherein, CO ₂ In the mixed gas with Ar, the volume ratio of CO ₂ and Ar is 1:1;

The other way is the same.

Application example 1

The silicon-based Si-B-C negative electrode material prepared in Example 1, the conductive agent acetylene black and the binder PVDF are in mass ratio, the silicon-based Si-B-C negative electrode material: conductive agent acetylene black: binder PVDF=6:2:2 The ratio is uniformly mixed, and the solvent N-methylpyrrolidone is added to prepare a slurry, and the slurry is coated on the copper foil current collector to obtain an electrode sheet;

The electrode sheet was placed in vacuum drying and dried at 90°C for 12 h. After the electrode sheet was completely dried, the electrode sheet was punched into a circular electrode sheet with a diameter of 12 mm.

The obtained circular electrode sheet was used as the negative electrode, the metal lithium sheet was used as the positive electrode, Celgard2400 was used as the separator, and EC/DMC (1:1)-LiPF6 (1M) was used as the electrolyte, and the battery was assembled in a glove box.

Use the blue CT2001A battery test system to perform constant current charge and discharge tests within the voltage range of 0.01 to 1.5V. The electrochemical test results show that the coulombic efficiency of the first charge and discharge is 84%, and the reversible cycle specific capacity of the battery is 1234.6mAh·g ^{-1 after 400 cycles at a current density of 0.1A·g -1 .}

Application example 2

The silicon-based Si-B-C negative electrode material prepared in Example 2 is applied, the same as in Application Example 1, except that:

(1) The coulombic efficiency of the first charge and discharge is 83%, and the reversible cycle specific capacity of the battery is 1317.3 mAh·g ^-1 after 400 cycles at a current density of 0.1 A·g ^-1 . The other way is the same.

Application example 3

The silicon-based Si-B-C negative electrode material prepared in Example 3 is applied, the same as in Application Example 1, except that:

(1) The coulombic efficiency of the first charge and discharge is 81%, and the reversible cycle specific capacity of the battery is 1399.6 mAh·g ^-1 after 400 cycles at a current density of 0.1 A·g ^-1 . The other way is the same.

Application example 4

The silicon-based Si-B-C negative electrode material prepared in Example 4 is applied, the same as in Application Example 1, except that:

(1) The coulombic efficiency of the first charge and discharge is 80%, and the reversible cycle specific capacity of the battery is 1431.7mAh·g ^{-1 after 400 cycles at a current density of 0.1A·g -1 .} The other way is the same.

Application example 5

The silicon-based Si-B-C negative electrode material prepared in Example 5 is applied, the same as in Application Example 1, except that:

(1) The coulombic efficiency of the first charge and discharge is 79%, and the reversible cycle specific capacity of the battery is 1482.6mAh·g ^{-1 after 400 cycles at a current density of 0.1A·g -1 .} The other way is the same.

Application example 6

The silicon-based Si-B-C negative electrode material prepared in Example 26 is applied, the same as in Application Example 1, except that:

(1) The coulombic efficiency of the first charge and discharge is 82%, and the reversible cycle specific capacity of the battery is 1385.6 mAh·g ^-1 after 400 cycles at a current density of 0.1 A·g ^-1 . The other way is the same.

Application example 7

The silicon-based Si-B-C negative electrode material prepared in Example 21 was applied, the same as in Application Example 1, except that:

(1) The coulombic efficiency of the first charge and discharge is 83%, and the reversible cycling specific capacity of the battery is 1330.6 mAh·g ^-1 after 400 cycles at a current density of 0.1 A·g ^-1 . The other way is the same.

Application example 8

The silicon-based Si-B-C negative electrode material prepared in Example 16 is applied, the same as in Application Example 1, except that:

(1) The coulombic efficiency of the first charge and discharge is 80%, and the reversible cycle specific capacity of the battery is 1450.1 mAh·g ^-1 after 400 cycles at a current density of 0.1 A·g ^-1 . The other way is the same.

Application example 9

The silicon-based Si-B-C negative electrode material prepared in Example 11 is applied, the same as in Application Example 1, except that:

(1) The coulombic efficiency of the first charge and discharge is 79%, and the reversible cycle specific capacity of the battery is 1500.6mAh·g ^{-1 after 400 cycles at a current density of 0.1A·g -1 .} The other way is the same.

Application example 10

The silicon-based Si-B-C negative electrode material prepared in Example 6 is applied, the same as in Application Example 1, except that:

(1) The coulombic efficiency of the first charge and discharge is 78%, and the reversible cycle specific capacity of the battery is 1510.7mAh·g ^{-1 after 400 cycles at a current density of 0.1A·g -1 .} The other way is the same.

Application example 11

The silicon-based Si-B-C negative electrode material prepared in Example 61 is the same as in Application Example 1, except that:

(1) The coulombic efficiency of the first charge and discharge is 79%, and the reversible cycle specific capacity of the battery is 1334.6mAh·g ^{-1 after 500 cycles at a current density of 0.1A·g -1 .}

Application example 12

The silicon-based Si-B-C negative electrode material prepared in Example 73 was applied, the same as in Application Example 11, except that:

(1) The coulombic efficiency of the first charge and discharge is 78%, and the reversible cycle specific capacity of the battery is 1317.3 mAh·g ^-1 after 500 cycles at a current density of 0.1 A·g ^-1 . The other way is the same.

Application example 13

The silicon-based Si-B-C negative electrode material prepared in Example 74 was applied, the same as in Application Example 11, except that:

(1) The coulombic efficiency of the first charge and discharge is 76%, and the reversible cycle specific capacity of the battery is 1399.6 mAh·g ^-1 after 500 cycles at a current density of 0.1 A·g ^-1 . The other way is the same.

Application example 14

The silicon-based Si-B-C negative electrode material prepared in Example 75 was applied, the same as in Application Example 11, except that:

(1) The coulombic efficiency of the first charge and discharge is 75%, and the reversible cycle capacity of the battery is 1441.7 mAh·g ^-1 after 500 cycles at a current density of 0.1 A·g ^-1 . The other way is the same.

Application example 15

The silicon-based Si-B-C negative electrode material prepared in Example 76 was applied, the same as in Application Example 11, except that:

(1) The coulombic efficiency of the first charge and discharge is 74%, and the reversible cycle capacity of the battery is 1487.6 mAh·g ^{-1 after 500 cycles at a current density of 0.1 A·g -1 .} The other way is the same.

Application example 16

The silicon-based Si-B-C negative electrode material prepared in Example 77 was applied, the same as in Application Example 11, except that:

(1) The coulombic efficiency of the first charge and discharge is 77%, and the reversible cycle specific capacity of the battery is 1385.6 mAh·g ^-1 after 500 cycles at a current density of 0.1 A·g ^-1 . The other way is the same.

Claims (10)

1. Based on CO₂The preparation method of the prepared silicon-based Si-B-C cathode material is characterized by comprising the following steps of:

step 1: preparation of

(1) Respectively drying the boron-containing oxide and the molten salt raw material, and removing water; wherein the molten salt is: calcium chloride-based molten salt or calcium chloride-magnesium chloride-based molten salt;

the boron-containing oxide is one or a mixture of more of boron oxide, borax, calcium borate, magnesium borate and potassium borate;

the calcium chloride-based molten salt is one of calcium chloride, calcium chloride-sodium chloride, calcium chloride-potassium chloride and calcium chloride-sodium chloride-potassium chloride, wherein the calcium chloride-based molten salt and the calcium chloride are main salts;

the calcium chloride-magnesium chloride-based fused salt is one of calcium chloride-magnesium chloride, calcium chloride-magnesium chloride-sodium chloride, calcium chloride-magnesium chloride-potassium chloride and calcium chloride-magnesium chloride-potassium chloride-sodium chloride, wherein in the calcium chloride-magnesium chloride-based fused salt, the calcium chloride-magnesium chloride is a main salt, and the molar ratio of calcium chloride to magnesium chloride is as follows: the magnesium chloride is more than or equal to 1;

(2) under the protection of inert gas, respectively grinding the silicon-calcium alloy, the boron-containing oxide and the molten salt raw materials according to the proportion until the materials are uniform, then uniformly mixing, and sealing the obtained mixed material;

(3) placing the mixed material in an embedded crucible of a reactor, and sealing;

(4) introducing inert gas into the sealed reactor, maintaining the inert atmosphere in the reactor, ensuring positive pressure in the reactor, and raising the temperature of the reactor while introducing the inert gas;

step 2: synthesis of

When the temperature of the reactor is raised to the synthesis temperature, keeping the temperature constant, and introducing CO into the molten salt in the reactor₂Ventilating for 1-2 h, standing, and reacting at constant temperature for 1-5 h to obtain a reacted product; wherein the synthesis temperature is 530-900 ℃; wherein, CO₂The flow rate is less than or equal to 400 mL/min;

and step 3: post-treatment

Cooling the reacted product in a cooling container, grinding, washing with hydrochloric acid to remove molten salt, filtering, washing with water, and drying to obtain the product based on CO₂The prepared silicon-based Si-B-C cathode material.

2. CO-based according to claim 1₂The preparation method of the prepared silicon-based Si-B-C cathode material is characterized in that in the step 1(1), the process for removing moisture comprises the following steps: and (3) placing the raw material in a high-temperature vacuum drying furnace, drying for 10-15 h at the temperature of 300-400 ℃ and under the pressure of-0.1 MPa, and removing adsorbed water and crystal water to obtain a dried molten salt raw material.

3. CO-based according to claim 1₂The preparation method of the prepared silicon-based Si-B-C negative electrode material is characterized in that in the step 1(2), when the molten salt is calcium chloride-based molten salt, the boron-containing oxide contains boron oxide, and the molar ratio of the boron oxide to the CaSi in the silicon-calcium alloy₂: boron oxide is more than or equal to 3; in terms of mole ratio, chlorineCalcium chloride in calcium-based molten salt: CaSi in silicon-calcium alloy₂≥10；

When the molten salt is calcium chloride-based molten salt, the boron-containing oxide contains CaB₂O₄In terms of molar ratio, CaSi in Si-Ca alloy₂: calcium borate is more than or equal to 3; calcium chloride in the calcium chloride-based molten salt is as follows according to molar ratio: calcium borate is more than or equal to 40: 3;

when the fused salt is calcium chloride-based fused salt, the boron-containing oxide contains borax and CaSi in the silicon-calcium alloy according to the molar ratio₂: borax is more than or equal to 6; calcium chloride in the calcium chloride-based molten salt is as follows according to molar ratio: borax is more than or equal to 71: 3;

when the molten salt is calcium chloride-based molten salt, the boron-containing oxide contains magnesium borate, and the CaSi in the silicon-calcium alloy is added according to the molar ratio₂: the magnesium borate is more than or equal to 3; calcium chloride in the calcium chloride-based molten salt is as follows according to molar ratio: magnesium borate is more than or equal to 10;

when the molten salt is calcium chloride-based molten salt, the boron-containing oxide contains potassium borate, and the CaSi in the silicon-calcium alloy is added according to the molar ratio₂: the potassium borate is more than or equal to 6; calcium chloride in the calcium chloride-based molten salt is as follows according to molar ratio: the ratio of potassium borate to potassium borate is more than or equal to 71: 3.

4. CO-based according to claim 1₂The preparation method of the prepared silicon-based Si-B-C cathode material is characterized in that in the step 2, after the temperature of the reactor is raised to the synthesis temperature, the temperature is kept constant, the stirring paddle is inserted into the molten salt, the stirring is maintained in the processes of ventilation and constant temperature reaction, and the rotating speed of the stirring paddlevIs 0<v≤700r/min。

5. Based on CO₂The prepared silicon-based Si-B-C cathode material is characterized by being prepared by the preparation method of any one of claims 1 to 4.

6. CO-based according to claim 5₂The prepared silicon-based Si-B-C anode material is characterized in that the silicon-based Si-B-C anode material is based on CO₂The prepared silicon-based Si-B-C cathode material is based on CO when Si-B-C is statically synthesized₂The particle size of the prepared silicon-based Si-B-C negative electrode material is 1-50 mu m; while stirringFor the synthesis of Si-B-C, based on CO₂The particle size of the prepared silicon-based Si-B-C negative electrode material is 50nm-500 nm.

7. CO-based according to claim 5₂The application of the prepared silicon-based Si-B-C cathode material is characterized in that the silicon-based Si-B-C cathode material is based on CO₂The prepared silicon-based Si-B-C negative electrode material is used as a negative electrode material of a lithium ion battery.

8. A negative electrode material comprising the CO-based material according to claim 5₂And preparing the Si-B-C cathode material.

9. An electrode sheet, characterized by comprising the negative electrode material according to claim 8, and further comprising a binder, a conductive agent, and a solvent.

10. A lithium ion battery, characterized in that, the lithium ion battery comprises the electrode slice of claim 9, and a silicon-based Si-B-C anode material which is statically synthesized, and the first charge-discharge coulombic efficiency of the silicon-based Si-B-C anode material is improved>75 percent, the first discharge specific capacity of 3800mAh/g, which is 0.1 A.g^-1Current density cycle 400 cycles with reversible specific cycle capacity>1200 mAh/g; stirring synthesized silicon-based Si-B-C anode material with first charge-discharge coulombic efficiency>70% by weight of 0.1 A.g^-1Current density cycle 500 cycles with reversible specific cycle capacity>1300mAh/g。