CN112531160B

CN112531160B - Amorphous carbon negative electrode material and preparation method and application thereof

Info

Publication number: CN112531160B
Application number: CN201910886050.7A
Authority: CN
Inventors: 胡龙丰; 汪福明; 徐晓东; 任建国; 贺雪琴
Original assignee: BTR New Material Group Co Ltd
Current assignee: BTR New Material Group Co Ltd
Priority date: 2019-09-19
Filing date: 2019-09-19
Publication date: 2024-08-16
Anticipated expiration: 2039-09-19
Also published as: CN112531160A

Abstract

The invention provides an amorphous carbon anode material, a preparation method and application thereof. The amorphous carbon cathode material comprises a foam carbon skeleton and carbon particles embedded in the foam carbon skeleton, and the surface of the amorphous carbon cathode material comprises macropores and micropores. The preparation method comprises the following steps: (1) Reacting carbon particles with an organic complex to obtain a sol; (2) Adding a curing expanding agent into the sol to react to obtain a composite material; (3) And sintering the composite material to obtain the amorphous carbon anode material. The material has a concave-convex structure similar to the surface of lotus leaves, and the special structure not only can resist adsorptivity, but also can provide a fast diffusion channel for reaction ions, and has excellent high-rate long-cycle performance in energy storage application.

Description

Amorphous carbon negative electrode material and preparation method and application thereof

Technical Field

The invention belongs to the technical field of energy storage materials, relates to a negative electrode material, a preparation method and application thereof, and in particular relates to an amorphous carbon negative electrode material, a preparation method and application thereof.

Background

The development of electric automobiles, smart grids, mobile phones, notebook computers and the like is increasingly dependent on the development of lithium ion batteries due to the concept of green environmental protection and consumer requirements. At present, the cathode material of the commercial lithium ion battery is mainly made of carbon material, has high specific capacity (200-400 mAh.g < -1 >), low electrode potential (less than 1.0V vs Li ⁺/Li), good cycle performance (more than 1000 weeks) and stable physicochemical property. Carbon materials can be classified into graphite materials and amorphous carbon materials according to the difference of crystallization degree. The graphite material has the characteristics of good conductivity, high crystallinity, stable layered structure, suitability for intercalation-deintercalation of lithium and the like, and becomes an ideal lithium battery anode material. At present, the reversible capacity value of the graphite negative electrode material is close to the theoretical capacity value of 372mAh/g, the structural stability of the graphite material is poor, the compatibility with electrolyte is poor, the diffusion speed of Li ⁺ in an ordered layered structure is low, and the like, so that the conventional graphite negative electrode material is difficult to meet the requirements of a lithium ion power battery for quick charge and high-rate discharge. Thus, amorphous carbon negative electrode materials having high conductivity and excellent structural stability are becoming an important development point for researchers.

The amorphous carbon material has a short-range ordered long-range staggered layered structure, li ⁺ can be inserted and extracted from various angles, the ion diffusion distance is shortened, and the charge and discharge speed is greatly improved, so that the rapid charge and discharge of the material is realized. In addition, a large number of micropores and defects exist in the amorphous material structure, so that abundant active sites are provided for lithium intercalation, and the reversible capacity is far greater than the theoretical capacity value 372mAh/g of graphite. In addition, the amorphous carbon has isotropic structural characteristics, the interlayer spacing is larger, the Li ⁺ can realize rapid diffusion rate in the electrode even at the low temperature of minus 40 ℃, and the low-temperature performance is obviously improved compared with that of a graphite material. Therefore, amorphous carbon negative electrode materials become a development trend of negative electrode materials of future power batteries. Although amorphous carbon anode materials have many advantages, there are many problems in the application process, such as: (1) The surface defects of the material are more, the first irreversible capacity is larger, and the energy density of the battery is reduced; (2) Active sites rich in the surface of the material undergo side reactions with electrolyte at high temperature, so that the capacity is rapidly attenuated; (3) Although the amorphous carbon material has more excellent multiplying power performance than the graphite anode material, can charge and discharge at a high multiplying power of 20C@1C, has poorer long-cycle performance for the high multiplying power, and can not meet the increasingly larger power requirement of the market; (4) When the material is exposed in the air for a period of time, oxygen-containing functional groups such as-OH, -COOH, -C=O and the like in the structure of the material can generate chemical adsorption, and impurity gases such as water, oxygen and the like in the air are adsorbed, so that the reversible capacity is reduced sharply. Therefore, the popularization and application of the amorphous carbon material are limited.

In the prior art, there are many processes for improving the performances of negative electrode materials such as graphite, silicon carbon, amorphous carbon and the like, for example, CN105449162 discloses a negative electrode material for a lithium ion battery and a negative electrode plate thereof.

CN109671943a discloses a high first-efficiency silicon-carbon composite negative electrode material and a preparation method thereof, and the scheme coats a shell similar to SEI component on the surface of nano silicon by a physical vapor deposition and electrochemical deposition method to reduce the consumption of lithium ions in the first charge and discharge process.

CN106876710a discloses a soft carbon negative electrode material for lithium ion battery and a preparation method thereof, the proposal is that ammonium molybdate and cobalt nitrate are added into soft carbon precursor raw materials to consume simple substance or ionic sulfur (nitrogen) in the negative electrode, so as to improve the first effect of the material.

CN109148843a discloses a boron doped anode material with good high temperature performance and a solid phase preparation method thereof, the proposal uses boron oxide compound as doping agent to improve graphitization degree of the material by utilizing catalytic action of boron on one hand, on the other hand, boron oxide is compounded with the surface of the anode material, surface defect is reduced, and side reaction with electrolyte at high temperature is reduced.

The solution can effectively improve the first coulombic efficiency and the high-temperature performance of the anode material, but the problem that the performance of the anode material is greatly reduced due to the adsorption of impurity gases (water, oxygen and the like) in the air after the anode material is placed in the air for a period of time cannot be solved. In particular, the adsorption reaction mechanism of the amorphous carbon anode material exposed to air is complex, and few reports for improving the adsorptivity of the amorphous carbon anode material are provided at present, so that the process optimization development of a technology for preparing the anti-adsorption amorphous anode material is needed.

Disclosure of Invention

Aiming at the problems in the prior art, the invention aims to provide an amorphous carbon anode material, a preparation method and application thereof. The amorphous carbon negative electrode material provided by the invention has high specific mass capacity and high rate charge-discharge cycle retention, is strong in anti-adsorptivity, is exposed in the air and is placed for a plurality of days, and the electrochemical performance retention rate is excellent, so that the problem of performance attenuation of the amorphous carbon negative electrode material after being placed for a long time is effectively solved.

To achieve the purpose, the invention adopts the following technical scheme:

In a first aspect, the present invention provides an amorphous carbon negative electrode material comprising a foam carbon skeleton and carbon particles embedded in the foam carbon skeleton, the surface of the amorphous carbon negative electrode material comprising macropores and micropores.

The amorphous carbon negative electrode material provided by the invention is a carbon negative electrode material with high capacity and high multiplying power. The material has a three-dimensional hierarchical pore structure: 1) The macroporous structure of the foam carbon skeleton provides a rapid electrolyte ion transmission channel, which is beneficial to high-current charge and discharge and improves the rate capability; 2) The material has a superfluous surface structure, provides abundant active sites for energy storage reaction, and is beneficial to improving the mass specific capacity of the material; 3) The carbon particle cores are embedded in the foam carbon skeleton to form an integrated self-supporting porous structure, so that the contact internal resistance among the carbon particles is reduced, and the electronic conductivity of the material is improved. The amorphous carbon cathode material provided by the invention also has anti-adsorptivity. The surface of the material has dense nano-scale ultramicropores, so that strong capillary action is generated, and the adsorption energy barrier is increased, thereby reducing the adsorptivity of the material.

The foam carbon skeleton is similar to foam carbon in structure, contains a large number of macropores and is similar to foam. In the present invention, the foam carbon skeleton may be regarded as a carbon skeleton having a foam carbon structure.

The embedding means that carbon particles enter a foam carbon skeleton, and the foam carbon skeleton coats the carbon particles. The foam carbon skeleton may contain a plurality of carbon particles, i.e., it serves as a "bridge" connecting the plurality of carbon particles (host material).

The following preferred technical solutions are used as the present invention, but not as limitations on the technical solutions provided by the present invention, and the technical objects and advantageous effects of the present invention can be better achieved and achieved by the following preferred technical solutions.

As a preferable technical scheme of the invention, the amorphous carbon anode material has a rough structure. The rough structure refers to the appearance of the surface of the material similar to concave-convex folds, and the folds describe a super-micropore structure with developed surface of the material, and the aperture of the super-micropore is less than 1.0nm. The structure forms a "concave-convex" like roughness of the lotus leaf surface. The coarse structure prevents impurity gas in the air from entering the material structure, so that the capacity and the first effect of the material are hardly attenuated after the material is placed in the air.

Preferably, the amorphous carbon anode material is an integrated self-supporting structure. The integrated carbon skeleton and carbon particles are connected through chemical bonding to form a single integral structure, the self-supporting carbon material is stable in three-dimensional structure, and the self-supporting carbon material can be directly used as an electrode without adding a conductive agent.

Preferably, the amorphous carbon cathode material has a three-dimensional hierarchical pore structure, wherein the three-dimensional structure refers to a space three-dimensional structure, and macropores and micropores are connected with each other. .

In a preferred embodiment of the present invention, the carbon particles account for 70-98%, such as 70%, 75%, 80%, 85%, 90%, 95% or 99% of the total mass of the amorphous carbon negative electrode material, but are not limited to the recited values, and other non-recited values within the range are equally applicable, preferably 80-95%.

Preferably, the foam carbon skeleton has a thickness of 0-1.5 μm and does not include 0, such as 0.1 μm, 0.2 μm, 0.3 μm, 0.4 μm, 0.5 μm, 0.6 μm, 0.7 μm, 0.8 μm, 0.9 μm, 1 μm, 1.1 μm, 1.2 μm, 1.3 μm, 1.4 μm, or 1.5 μm, etc. Here, if the foam carbon skeleton is too thick, it may cause a decrease in the compacted density of the amorphous carbon negative electrode material, a decrease in the electrical conductivity, and a decrease in the energy density and the rate capability; if the foam carbon skeleton is too thin, the coating is uneven, carbon particles are exposed, and the effect of reducing the adsorptivity of hard carbon cannot be achieved.

Preferably, the macropores have a pore diameter of 0.2 to 3 μm, for example, 0.2 μm, 0.5 μm, 1 μm, 2 μm, or 3 μm, etc., but are not limited to the recited values, and other non-recited values within the range of values are equally applicable.

Preferably, the pore diameter of the ultramicropore is 0 to 1.0nm and does not include 0, for example, 0.2nm, 0.3nm, 0.4nm, 0.5nm, 0.6nm, 0.7nm, 0.8nm, 0.9nm or 1.0nm, etc., but is not limited to the recited values, and other non-recited values within the range of values are equally applicable, preferably 0 to 0.6nm and does not include 0. Here, if the pore diameter of the ultra-micropores is too large, the contact surface between the material and water increases, the capillary action decreases, which results in a decrease in hydrophobicity, and the effect of decreasing the adsorptivity of the material cannot be achieved; in addition, ultra-micropores with too large pore sizes increase the irreversible reactive sites of the material and the electrolyte, resulting in a decrease in the first effect.

Preferably, the amorphous carbon anode material has a total pore volume of 0.5-2.0cm ³/g, such as 0.5cm³/g、0.8cm³/g、1.0cm³/g、1.2cm³/g、1.5cm³/g、1.8cm³/g、2.0cm³/g, etc., but is not limited to the recited values, as other non-recited values within this range are equally applicable.

Preferably, in the amorphous carbon negative electrode material, the pore volume of the ultramicropores accounts for 30-85% of the total pore volume, for example, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, etc., but the amorphous carbon negative electrode material is not limited to the recited values, and other non-recited values within the range of the values are equally applicable.

Preferably, in the amorphous carbon negative electrode material, the pore volume of the macropores accounts for 13-70% of the total pore volume, for example, 13%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65% or 70%, etc., but is not limited to the recited values, and other non-recited values within the range of the values are equally applicable.

Preferably, the amorphous carbon negative electrode material has a median particle diameter of 8.0 to 40.0 μm, for example, 8.0 μm, 10.0 μm, 14.0 μm, 18.0 μm, 22.0 μm, 26.0 μm, 30.0 μm, 34.0 μm, 38.0 μm, 40.0 μm, or the like, but is not limited to the recited values, and other non-recited values within the range of values are equally applicable, preferably 15.0 to 30.0 μm.

Preferably, the carbon particles have a median particle diameter of 0.2 to 3.0 μm, for example 0.2 μm, 0.4 μm, 0.6 μm, 0.8 μm, 1.0 μm, 1.2 μm, 1.4 μm, 1.6 μm, 1.8 μm, 2.0 μm, 2.2 μm, 2.4 μm, 2.6 μm, 2.8 μm or 3.0 μm, etc. However, the present invention is not limited to the values listed, and other values not listed in the range are equally applicable, and preferably 0.5 to 2.0. Mu.m.

Preferably, the amorphous carbon negative electrode material has a specific surface area of 1 to 50m ²/g, such as 1m²/g、5m²/g、10m²/g、15m²/g、20m²/g、25m²/g、30m²/g、35m²/g、40m²/g、45m²/g or 50m ²/g, etc., but is not limited to the recited values, and other non-recited values within the range of values are equally applicable, preferably 1 to 35m ²/g.

Preferably, the powder contact angle of the amorphous carbon anode material with water is 40-85 °, for example 40 °, 45 °,50 °, 55 °, 60 °, 65 °, 70 °, 75 °, 80 ° or 85 °, etc., but is not limited to the recited values, and other non-recited values within the range of values are equally applicable. In the invention, the numerical value of the powder contact angle is used for measuring the adsorption capacity of the amorphous carbon anode material to water, and the 0 DEG datum line is the powder contact angle between the amorphous carbon anode material and cyclohexane.

In a second aspect, the present invention provides a method for preparing the amorphous carbon anode material according to the first aspect, the method comprising the steps of:

(1) Reacting carbon particles with an organic complex to obtain a sol;

(2) Adding a curing expanding agent into the sol in the step (1) to react to obtain a composite material;

(3) And (3) sintering the composite material in the step (2) to obtain the amorphous carbon anode material.

In the preparation method provided by the invention, a sol-gel auxiliary process is adopted, a curing expanding agent is added, and the three-dimensional foam type hierarchical pore amorphous carbon anode material is prepared by polymerization at low temperature and high temperature sintering etching. Specifically, the carbon particles with a certain size and the organic complex are stirred under the condition of low-temperature heating to perform polymerization reaction to form black sticky sol, and then a curing expansion agent is added to perform curing action so as to crosslink and cure the black sticky sol. Simultaneously, the curing expansion agents are decomposed under the heating condition to generate nanoscale metal oxide and gas micromolecular substances, the gas micromolecules enable the sol to expand and foam, the expansion effect is achieved, redundant solvents are removed through a flash drying mode to form a foam type composite material, and the self-supporting three-dimensional hierarchical pore amorphous carbon material is obtained after high-temperature sintering. Because the nano metal oxide exists in the composite material, the nano metal oxide can react with the carbon matrix material at high temperature to generate etching effect, and a developed ultra-microporous structure, namely a rough structure similar to the lotus leaf surface, is formed on the surface, so that the aim of resisting adsorptivity is fulfilled. Meanwhile, the metal simple substance generated after the etching reaction can promote skeleton rearrangement, improve the graphitization degree of the organic complex pyrolytic carbon and improve the first effect.

As a preferred embodiment of the present invention, the carbon particles of step (1) have a median particle diameter of 0.2 to 3.0. Mu.m, for example, 0.2. Mu.m, 0.4. Mu.m, 0.6. Mu.m, 0.8. Mu.m, 1.0. Mu.m, 1.2. Mu.m, 1.4. Mu.m, 1.6. Mu.m, 1.8. Mu.m, 2.0. Mu.m, 2.2. Mu.m, 2.4. Mu.m, 2.6. Mu.m, 2.8. Mu.m, 3.0. Mu.m, etc. However, the present invention is not limited to the values listed, and other values not listed in the range are equally applicable, and preferably 0.5 to 2.0. Mu.m. Here, if the carbon particles are too small, the more macropores are generated in the material, the lower the compaction density is, resulting in low energy density, and at the same time, the excessive pore structure consumes a large amount of electrolyte, reducing the initial efficiency; if the carbon particles are too large, the organic complex pyrolyses the carbon coating unevenly, even in the direct uncoated areas.

Preferably, the mass ratio of carbon particles to organic complex in step (1) is 1 (0.5-8), e.g. 1:0.5, 1:1, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7 or 1:8, etc., preferably 1 (1-6).

In the invention, if the carbon particles are too much compared with the organic complex, the organic complex cannot completely wrap the carbon particles into a uniform coating layer, and cannot self-assemble into a three-dimensional conductive network structure; if the carbon particles are too small relative to the organic complex, this can result in too much macroporous structure and a lower compacted density.

Preferably, the method of reacting carbon particles with an organic complex of step (1) comprises: adding carbon particles into the solution of the organic complex, and heating for reaction to obtain the sol.

Preferably, the mass fraction of the organic complex in the solution of the organic complex is 10 to 90%, for example 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80% or 90%, etc., but is not limited to the recited values, and other non-recited values within the range of values are equally applicable, preferably 40 to 70%. Here, if the concentration is too small, gel cannot be formed; the organic complex and the carbon particles are difficult to mix uniformly due to the excessive concentration.

Preferably, the organic complex comprises any one or a combination of at least two of sucrose, starch, gelatin, a thermoplastic phenolic resin, polypyrrole, polyaniline or polyvinyl alcohol. Typical but non-limiting combinations are: a combination of sucrose and starch, a combination of starch and gelatin, a combination of gelatin and a thermoplastic phenolic resin, a combination of a thermoplastic phenolic resin and polypyrrole, a combination of polypyrrole and polyaniline, a combination of polyaniline and polyvinyl alcohol, and the like. The organic complex preferably has better sol effect at low temperature, contains rich nitrogen element and improves the capacity.

Preferably, the solvent in the solution of the organic complex comprises any one or a combination of at least two of water, ether, alcohol, ketone or tetrahydrofuran.

The reaction temperature of the heating reaction is preferably 40 to 100 ℃, for example 40 ℃, 50 ℃, 60 ℃, 70 ℃, 80 ℃, 90 ℃, or 100 ℃, etc., but is not limited to the recited values, and other non-recited values within the range of values are equally applicable.

Preferably, the reaction time of the heating reaction is 1 to 12 hours, for example, 1 hour, 2 hours, 4 hours, 6 hours, 8 hours, 10 hours, 12 hours, etc., but is not limited to the recited values, and other non-recited values within the range are equally applicable.

Preferably, the heating reaction is accompanied by stirring.

Preferably, the heating is performed with an oil bath.

Preferably, the stirring rate of the stirring is 10-90r/min, for example 10r/min, 20r/min, 30r/min, 40r/min, 50r/min, 60r/min, 70r/min, 80r/min or 90r/min, but is not limited to the recited values, and other non-recited values within the range of values are equally applicable, preferably 30-60r/min.

As a preferred technical scheme of the present invention, the curing expansion agent in the step (2) includes any one or a combination of at least two of sodium bicarbonate, sodium carbonate, sodium oxalate or calcium carbonate. The preferable composite salt can play a role in crosslinking and curing as well as an expansion promotion function, has a low decomposition temperature, can generate a large amount of gas micromolecular substances after decomposition to promote sol expansion, and can react with a carbon matrix at a high temperature to generate an etching micropore-forming function, and meanwhile, the reacted metal simple substance promotes carbon skeleton rearrangement to improve graphitization degree of the organic complex pyrolytic carbon.

Preferably, the mass ratio of the curing expanding agent to the carbon particles in step (2) is (0.02-0.8): 1, for example, 0.02:1, 0.05:1, 0.08:1, 0.1:1, 0.2:1, 0.3:1, 0.4:1, 0.5:1, 0.6:1, 0.7:1 or 0.8:1, etc., but is not limited to the recited values, and other non-recited values within the range of values are equally applicable, preferably (0.05-0.5): 1. In the invention, if the addition amount of the curing expanding agent is excessive, a large amount of gas is generated by decomposing the curing expanding agent in the curing reaction process, so that a rich macroporous structure is formed, the inner wall is thinned, and the product decomposed by the curing expanding agent is further etched at high temperature, so that the porous foam structure collapses; if the amount of the curing expanding agent added is too small, the degree of crosslinking becomes insufficient, the curing becomes incomplete, and at the same time, the gas generated by decomposition of the curing expanding agent is small, and a porous foam structure cannot be formed.

Preferably, the method of performing the reaction of step (2) comprises: and adding a curing expanding agent, mixing, stopping the mixing operation, performing heating reaction, and drying after the reaction to obtain the composite material. Here, the mixing operation (e.g., stirring mixing operation) is stopped during the heating reaction because the mixing operation may hinder the curing of the composite material while breaking the three-dimensional hierarchical pore structure formed by the crosslinking reaction.

Preferably, the method of mixing is stirring mixing.

Preferably, the stirring rate of the stirring and mixing is 10-90r/min, for example 10r/min, 20r/min, 30r/min, 40r/min, 50r/min, 60r/min, 70r/min, 80r/min or 90r/min, but is not limited to the recited values, and other non-recited values within the range of values are equally applicable, preferably 30-60r/min.

Preferably, the mixing time is from 0.5 to 3 hours, such as 0.5 hours, 1 hour, 2 hours, or 3 hours, etc., but is not limited to the recited values, and other non-recited values within the range of values are equally applicable.

The reaction temperature of the heating reaction is preferably 60 to 300 ℃, for example 60 ℃, 100 ℃, 150 ℃, 200 ℃, 250 ℃, 300 ℃ or the like, but is not limited to the recited values, and other non-recited values within the range of the recited values are equally applicable.

Preferably, the reaction time of the heating reaction is 0.5 to 10 hours, for example, 0.5 hours, 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours or 10 hours, etc., but is not limited to the recited values, and other non-recited values within the range of the values are equally applicable.

Preferably, the drying method is cooling drying or supercritical drying. Here, preferably, the two flash drying modes can rapidly remove the excessive solvent, and can also maintain the original three-dimensional foam structure of the sol.

As a preferred embodiment of the present invention, the sintering in step (3) is performed under a protective atmosphere.

Preferably, the protective atmosphere comprises any one or a combination of at least two of nitrogen atmosphere, helium atmosphere, neon atmosphere, argon atmosphere or xenon atmosphere.

Preferably, the sintering temperature in step (3) is 600-1500 ℃, for example 600 ℃, 700 ℃, 800 ℃, 900 ℃, 1000 ℃, 1100 ℃, 1200 ℃, 1300 ℃, 1400 ℃, 1500 ℃, etc., but is not limited to the recited values, and other non-recited values within the range of values are equally applicable.

Preferably, the sintering time in step (3) is 0.5-6h, such as 0.5h, 1h, 2h, 3h, 4h, 5h or 6h, etc., but is not limited to the recited values, and other non-recited values within the range are equally applicable.

Preferably, the temperature rising rate of the sintering in the step (3) is 1-30 ℃/min, such as 1 ℃/min, 3 ℃/min, 5 ℃/min, 7 ℃/min, 10 ℃/min, 13 ℃/min, 15 ℃/min, 17 ℃/min, 20 ℃/min or 30 ℃/min, etc., but is not limited to the recited values, and other non-recited values within the range of values are equally applicable, preferably 1-15 ℃/min.

Preferably, the sintered reactor of step (3) comprises any one or a combination of at least two of a vacuum furnace, a box furnace, a tube furnace, a roller kiln, a pusher kiln, a microwave pyrolysis furnace, or an ultraviolet pyrolysis furnace.

Preferably, step (3) further comprises: cooling to 15-35 deg.c after sintering, i.e. cooling to room temperature.

Preferably, step (3) further comprises: and purifying the product obtained after sintering. In the present invention, the purification aims at removing metallic salt impurities generated during the reaction.

Preferably, the purification method comprises: and (3) stirring and mixing the sintered product with acid, carrying out suction filtration, washing the obtained solid with water to be neutral, centrifuging and drying, and carrying out demagnetizing and screening on the dried product to obtain the amorphous carbon anode material.

Preferably, the mass ratio of the product obtained after sintering to the acid is 1:2-1:50, such as 1:2, 1:5, 1:10, 1:15, 1:20, 1:25, 1:30, 1:35, 1:40, 1:45 or 1:50, etc., but is not limited to the recited values, other non-recited values within the range of values are equally applicable, preferably 1:5-1:20.

Preferably, the acid comprises any one or a combination of at least two of hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, boric acid or oxalic acid.

Preferably, the concentration of the acid is 1 to 5mol/L, for example 1.0mol/L, 1.5mol/L, 2.0mol/L, 2.5mol/L, 3.0mol/L, 3.5mol/L, 4.0mol/L, 4.5mol/L or 5.0mol/L, but is not limited to the recited values, and other non-recited values within this range of values are equally applicable.

Preferably, the stirring and mixing time is 0.5-10h, such as 0.5h, 1.0h, 2.0h, 3.0h, 4.0h, 5.0h, 6.0h, 7.0h, 8.0h, 9.0h or 10.0h, etc., but is not limited to the recited values, and other non-recited values within the range of values are equally applicable.

Preferably, the centrifugation time is 0.5-8h, such as 0.5h, 1.0h, 2.0h, 3.0h, 4.0h, 5.0h, 6.0h, 7.0h or 8.0h, etc., but is not limited to the recited values, and other non-recited values within the range are equally applicable, preferably 1.5-5h.

Preferably, the drying is performed in a vacuum drying oven, a forced air drying oven, a box furnace, a rotary kiln or a double cone dryer.

Preferably, the drying temperature is 50 to 200 ℃, for example 50 ℃, 80 ℃, 100 ℃, 120 ℃, 150 ℃, 180 ℃, or 200 ℃, etc., but is not limited to the recited values, and other non-recited values within the range of the recited values are equally applicable, preferably 80 to 150 ℃.

Preferably, the drying time is 5-48 hours, such as 5 hours, 10 hours, 15 hours, 20 hours, 25 hours, 30 hours, 35 hours, 40 hours, or 48 hours, etc., but is not limited to the recited values, and other non-recited values within the range are equally applicable.

As a preferred technical scheme of the invention, the preparation method of the carbon particles in the step (1) comprises the following steps: carbonizing the carbon precursor in a protective atmosphere to obtain the carbon particles.

Preferably, the carbon precursor comprises any one or a combination of at least two of biomass, resin, pitch or coke.

Preferably, the biomass comprises any one or a combination of at least two of coconut shells, apricot shells, fruit shells or walnut shells.

Preferably, the resin comprises any one or a combination of at least two of furfural resin, phenolic resin, melamine formaldehyde resin, epoxy resin, unsaturated polyester, vinyl ester, bismaleimide resin, polyimide resin, polyethylene, polyvinyl chloride, polystyrene (PS), polypropylene or acrylonitrile-styrene-butadiene copolymer (ABS).

Preferably, the bitumen comprises any one or a combination of at least two of coal tar pitch, shale pitch or petroleum pitch.

Preferably, the char comprises any one or a combination of at least two of coal char, petroleum char, or mesophase carbon microbeads.

Preferably, the carbonization temperature is 300-850 ℃, for example 300 ℃, 400 ℃, 500 ℃, 600 ℃, 700 ℃, 800 ℃, 850 ℃ or the like, but is not limited to the recited values, and other non-recited values within the range of values are equally applicable.

Preferably, the carbonization time is 0.5-8h, such as 0.5h, 1h, 2h, 3h, 4h, 5h, 6h, 7h or 8h, etc., but is not limited to the recited values, and other non-recited values within the range of values are equally applicable.

Preferably, the carbonization temperature rise rate is 1-10 ℃ per minute, for example, 1 ℃ per minute, 2 ℃ per minute, 4 ℃ per minute, 6 ℃ per minute, 7 ℃ per minute, 8 ℃ per minute, 10 ℃ per minute, or the like, but not limited to the recited values, and other non-recited values within the range of values are equally applicable.

Preferably, the preparation method of the carbon particles further comprises the following steps: crushing and pulverizing the carbonized product.

As a further preferred technical solution of the preparation method according to the invention, the method comprises the following steps:

(1) Heating the carbon precursor to 300-850 ℃ at a heating rate of 1-10 ℃/min under a protective atmosphere for carbonization, wherein the carbonization time is 0.5-8h, cooling to 15-35 ℃ after carbonization, and crushing the carbonized product to obtain the carbon particles;

(2) Adding carbon particles into the solution of the organic complex, and heating and reacting under stirring at 40-100 ℃ for 1-12h to obtain sol;

Wherein the median particle diameter of the carbon particles is 0.5-2.0 mu m, the mass ratio of the carbon particles to the organic complex is 1 (1-6), and the mass fraction of the organic complex in the solution of the organic complex is 40-70%;

(3) Adding a curing expanding agent into the sol in the step (2), stirring and mixing for 0.5-3h, stopping stirring, heating and reacting at 60-300 ℃ for 0.5-10h, and drying after the reaction to obtain a composite material;

Wherein the curing expansion agent is any one or the combination of at least two of sodium bicarbonate, sodium carbonate, sodium oxalate or calcium carbonate, and the mass ratio of the curing expansion agent to the carbon particles is (0.05-0.5): 1; the drying method is cooling drying or supercritical drying;

(4) Heating the composite material in the step (3) to 600-1500 ℃ at a heating rate of 1-15 ℃/min under protective atmosphere, sintering for 0.5-6h, cooling to 15-35 ℃ after sintering, stirring and mixing the sintered product with acid with the concentration of 1-5mol/L for 0.5-10h at a mass ratio of 1:5-1:20, carrying out suction filtration, washing the obtained solid with water to be neutral, centrifuging for 1.5-5h, drying for 5-48h at 80-150 ℃, and carrying out demagnetization and screening on the dried product to obtain the amorphous carbon anode material.

In the further preferred technical scheme, the preferred curing expanding agent is added in the sol reaction, the curing expanding agent is decomposed at low temperature to generate a large amount of micromolecular gas substances for foaming expansion, the nano metal oxide generated by decomposing the curing expanding agent can be used as an activating agent for etching and pore-forming in the high-temperature sintering process, meanwhile, the metal simple substance obtained after the reaction can promote carbon skeleton rearrangement, the graphitization degree of the organic complex pyrolytic carbon is improved, and the three-dimensional foam amorphous carbon anode material is prepared after acid purification and impurity removal to form a 'concave-convex' structure similar to the surface of lotus leaves.

In a third aspect, the present invention provides the use of an amorphous carbon anode material according to the first aspect for a lithium ion battery, a sodium ion battery or a supercapacitor.

Compared with the prior art, the invention has the following beneficial effects:

(1) The invention uses organic complex as coating carbon source to form foam carbon skeleton, uses compound salt as solidifying expanding agent, and uses sol polymerization reaction and high-temperature heat treatment to design an amorphous carbon negative electrode material with integrated self-supporting three-dimensional hierarchical pore structure.

(2) The amorphous carbon anode material provided by the invention has a special three-dimensional hierarchical pore structure, wherein: a. the macroporous foam structure provides a rapid transmission channel for electrolyte ions, is favorable for large-current charge and discharge, has a retention rate of lithium intercalation capacity reaching 92.2% after 3000 times of circulation under the current density of 5C@5C, and is superior to the level of the existing amorphous carbon material (about 86% at the 800 weeks of 3C@3C); b. the surface of the amorphous carbon material is formed into a super-microporous rough structure similar to developed lotus leaves, the mass specific capacity of the material is improved, the first lithium removal capacity of the amorphous carbon material can reach 509.7mAh/g, the first coulomb efficiency of the amorphous carbon material can reach 84.6%, the adsorptivity of the material can be reduced, the powder contact angle of the material can be improved from 55 degrees to 78 degrees, the prepared amorphous carbon material is placed in the air for 30 days, the reversible capacity and the first coulomb efficiency are almost unchanged, the level of the amorphous carbon material is far superior to that of the existing amorphous carbon material (the capacity retention rate is about 90% in 30 days), and the problem of placing attenuation of the amorphous carbon material in the air is remarkably improved.

(3) The preparation method provided by the invention has the advantages of simple operation process, easily available raw materials, environmental friendliness, controllable morphology of the obtained amorphous carbon anode material and easiness in large-scale production.

Drawings

FIG. 1 is a scanning electron microscope picture of an amorphous carbon negative electrode material prepared in example 1 of the present invention;

FIG. 2 (a) is a graph showing the nitrogen adsorption curve of the amorphous carbon negative electrode material prepared in example 1 of the present invention;

FIG. 2 (b) is a pore size distribution curve of the amorphous carbon negative electrode material prepared in example 1 of the present invention;

FIG. 3 is the electrical conductivity of the amorphous carbon negative electrode material prepared in example 1 of the present invention;

FIG. 4 is a graph showing the first charge and discharge curves of the amorphous carbon negative electrode material prepared in example 1 of the present invention;

fig. 5 is a cycle performance curve of the amorphous carbon negative electrode material prepared in example 1 of the present invention.

Detailed Description

For better illustrating the present invention, the technical scheme of the present invention is convenient to understand, and the present invention is further described in detail below. The following examples are merely illustrative of the present invention and are not intended to represent or limit the scope of the invention as defined in the claims.

The following are exemplary but non-limiting examples of the invention:

example 1

The anti-adsorptivity amorphous carbon negative electrode material was prepared as follows:

(1) Placing 800g of coconut shells in a box furnace under nitrogen atmosphere, heating to 500 ℃ at a heating rate of 5 ℃/min, carbonizing for 6 hours, cooling to 25 ℃ to obtain 220g of carbonized material, crushing the carbonized material by using a ball mill, and crushing the medium particle size of the material to 1.5 mu m to obtain carbon particles;

(2) Adding 100g of carbon particles into 500g of gelatin aqueous solution with mass fraction of 60%, placing into an oil bath with a magnetic stirrer, heating to 60 ℃ and stirring for 8 hours to form uniformly mixed viscous sol;

(3) Adding 50g of sodium bicarbonate into the viscous sol, continuing stirring for 2 hours, stopping stirring, raising the temperature to 130 ℃, preserving heat for 4 hours, performing expansion reaction, and performing freeze drying to obtain a three-dimensional foam composite material with the mass of 420 g;

(4) Putting 420g of the three-dimensional foam composite material into a graphite crucible, placing the graphite crucible into a box-type furnace, introducing nitrogen protection gas, heating to 1300 ℃ at a heating rate of 5 ℃/min, preserving heat for 4 hours, cooling to room temperature, and taking out to obtain 140g of black mixture;

(5) Crushing the mixture obtained in the step (4), stirring and mixing the crushed mixture with 3mol/L dilute hydrochloric acid according to the mass ratio of 1:10, soaking for 4 hours, centrifugally washing to be neutral, drying the neutral in a 100 ℃ oven for 12 hours, and then taking the dried material to perform demagnetization and screening to obtain the anti-adsorptivity amorphous carbon negative electrode material.

The anti-adsorptivity amorphous carbon negative electrode material prepared in this example was subjected to structural test by the following method:

The specific surface area of the material was tested using a Tristar3000 fully automatic specific surface area and porosity analyzer from american microphone instruments.

The material particle size range and the average particle size of the raw material particles were tested using a malvern laser particle size tester MS 2000.

The surface morphology, particle size, etc. of the sample were observed using a Hitachi S4800 scanning electron microscope.

The amorphous carbon cathode material prepared by the embodiment comprises a foam carbon skeleton and carbon particles embedded in the foam carbon skeleton, wherein the surface of the amorphous carbon cathode material comprises macropores and micropores. The amorphous carbon cathode material has an integrated self-supporting structure and a three-dimensional hierarchical pore structure. The amorphous carbon cathode material has a rough structure.

In the amorphous carbon cathode material prepared by the embodiment, the mass of carbon particles accounts for 82% of the total mass of the amorphous carbon cathode material, the thickness of the foam carbon skeleton is 1.0 μm, the pore diameter of macropores is 0.2-2 μm, and the pore diameter of micropores is below 0.6 nm; the total pore volume of the amorphous carbon anode material is 1.8cm ³/g, wherein the pore volume of the ultra-micropores accounts for 70% of the total pore volume, and the macropores account for 28% of the total pore volume; the median particle diameter (D50) of the amorphous carbon negative electrode material is 21.388 mu m, the specific surface area is 22.5m ²/g, and the powder contact angle of the amorphous carbon negative electrode material and water is 61 degrees (the powder contact angle between the amorphous carbon negative electrode material and cyclohexane is a 0-degree datum line).

The results of the electrochemical test and the adsorption performance decay test of the amorphous carbon anode material prepared in this example are shown in table 1.

Fig. 1 is a scanning electron microscope picture of an amorphous carbon anode material prepared in this example, and it can be seen from this picture that the particle surface of the amorphous carbon anode material is rugged, has a rich macroporous structure, and has a particle size of about 21um.

Fig. 2 (a) is a nitrogen adsorption curve of the amorphous carbon anode material prepared in this example, fig. 2 (b) is a pore size distribution curve of the amorphous carbon anode material prepared in this example, it can be seen from fig. 2 (a) that an equipotential curve of the material is an iv-type isotherm, in a region near P/p0=0.1, the adsorption amount rapidly increases, corresponds to capillary adsorption of ultra-micropores, and when P/P0 continues to increase to be close to 1, the adsorption reaches saturation, the curve is flat, indicating that a microporous structure is mainly present in the material; as can be seen from the graph (b), the pore diameter of the material structure is mainly distributed at 0.3-0.6nm, and the material belongs to ultra-micropores;

FIG. 3 is a graph showing the conductivity of the amorphous carbon negative electrode material prepared in the present example, and the conductivity tester Mitsubishi ChemicalMCP-PD51 is a conductivity tester, from which it can be seen that the amorphous carbon negative electrode material exhibits an electron conductivity of 62.5S/cm under a pressure of 60 MPa;

FIG. 4 is a graph showing the first charge and discharge curves of the amorphous carbon negative electrode material prepared in this example, from which it can be seen that the lithium intercalation/deintercalation capacities of the amorphous carbon negative electrode material are 570mAh/g,482.1mAh/g, respectively;

fig. 5 is a cycle performance curve of the amorphous carbon negative electrode material prepared in this example, and it can be seen from this figure that the amorphous carbon negative electrode material circulates for 3000 weeks under 5C high-rate charge and discharge, and its capacity retention rate is close to 87.6%.

Example 2

(1) Placing 600g of asphalt in a box furnace under nitrogen atmosphere, heating to 650 ℃ at a heating rate of 3 ℃/min, carbonizing for 4 hours, cooling to 25 ℃ to obtain 200g of carbonized material, crushing by using a ball mill, and crushing the median particle size of the material to 1.0 mu m to obtain carbon particles;

(2) 200g of carbon particles are added into 250g of thermoplastic phenolic resin alcohol solution with the mass fraction of 40%, and the mixture is placed into an oil bath pot with a magnetic stirrer, heated to 55 ℃ and stirred for 10 hours to form a uniformly mixed viscous sol;

(3) Adding 60g of sodium oxalate into the viscous sol, continuously stirring for 3 hours, stopping stirring, raising the temperature to 260 ℃ and preserving heat for 4 hours, and performing freeze drying after expansion reaction to obtain 330g of three-dimensional foam composite material;

(4) Putting 330g of the three-dimensional foam composite material into a graphite crucible, placing the graphite crucible into a box-type furnace, introducing argon shielding gas, heating to 1100 ℃ at a heating rate of 2 ℃/min, preserving heat for 3 hours, cooling to room temperature, and taking out to obtain 240g of black mixture;

(5) Crushing the mixture obtained in the step (4), stirring and mixing the crushed mixture with 1mol/L dilute sulfuric acid according to the mass ratio of 1:15, soaking for 3 hours, centrifugally washing to be neutral, drying the neutral in a 120 ℃ oven for 10 hours, and then taking the dried material to perform demagnetization and screening to obtain the anti-adsorptivity amorphous carbon negative electrode material.

The amorphous carbon anode material obtained in this example was subjected to structural test by the method of example 1:

In the amorphous carbon cathode material prepared by the embodiment, the mass of carbon particles accounts for 88% of the total mass of the amorphous carbon cathode material, the thickness of the foam carbon skeleton is 0.6 mu m, the pore diameter of macropores is 0.4-3 mu m, and the pore diameter of ultramicropores is less than 0.83nm; the total pore volume of the amorphous carbon anode material is 1.841cm ³/g, wherein the pore volume of the ultra-micropores accounts for 68.5% of the total pore volume, and the macropores account for 29.7% of the total pore volume; the median particle diameter (D50) of the amorphous carbon negative electrode material is 15.284 mu m, the specific surface area is 38.2m ²/g, and the powder contact angle of the amorphous carbon negative electrode material and water is 52 degrees (the powder contact angle between the amorphous carbon negative electrode material and cyclohexane is a 0-degree datum line).

Example 3

(1) Placing 800g of apricot shells in a box furnace under nitrogen atmosphere, heating to 500 ℃ at a heating rate of 5 ℃/min, carbonizing for 6 hours, cooling to 25 ℃ to obtain carbonized materials, crushing the carbonized materials by using a ball mill, and crushing the median particle size of the materials to 0.5 mu m to obtain carbon particles;

(2) Adding 100g of carbon particles into 860g of gelatin aqueous solution with the mass fraction of 70%, placing the mixture into an oil bath with a mechanical stirrer, heating the mixture to 60 ℃ and stirring the mixture for 8 hours at 30r/min to form uniformly mixed viscous sol;

(3) Adding 5g of calcium carbonate into the viscous sol, continuing to stir for 2 hours at 30r/min, stopping stirring, heating to 130 ℃ and preserving heat for 4 hours, performing expansion reaction, and performing freeze drying to obtain a three-dimensional foam composite material;

(4) Placing the three-dimensional foam composite material into a graphite crucible, placing the graphite crucible into a box-type furnace, introducing nitrogen protection gas, heating to 1300 ℃ at a heating rate of 5 ℃/min, preserving heat for 4 hours, cooling to room temperature, and taking out to obtain a black mixture;

(5) Crushing the mixture obtained in the step (4), mixing with 3mol/L dilute hydrochloric acid according to a mass ratio of 1:5, soaking for 4 hours, centrifugally washing to be neutral, drying in an oven at 80 ℃ for 12 hours, and then taking the dried material to perform demagnetization and screening to obtain the anti-adsorptivity amorphous carbon negative electrode material.

In the amorphous carbon cathode material prepared by the embodiment, the mass of carbon particles accounts for 92% of the total mass of the amorphous carbon cathode material, the thickness of the foam carbon skeleton is 1.2 mu m, the pore diameter of macropores is 0.2-2 mu m, and the pore diameter of ultramicropores is less than 0.72nm; the total pore volume of the amorphous carbon anode material is 1.077cm ³/g, wherein the pore volume of the ultra-micropores accounts for 85.0% of the total pore volume, and the macropores account for 13.2% of the total pore volume; the median particle diameter (D50) of the amorphous carbon negative electrode material is 11.374 mu m, the specific surface area is 8.9m ²/g, and the powder contact angle of the amorphous carbon negative electrode material and water is 78 degrees (the powder contact angle between the amorphous carbon negative electrode material and cyclohexane is a 0-degree datum line). .

Example 4

(1) Placing 800g of walnut shells in a box furnace under nitrogen atmosphere, heating to 500 ℃ at a heating rate of 5 ℃/min, carbonizing for 6 hours, cooling to 25 ℃ to obtain carbonized materials, crushing the carbonized materials by using a ball mill, and crushing the median particle size of the materials to 2.0 mu m to obtain carbon particles;

(2) Adding 100g of carbon particles into 200g of starch aqueous solution with the mass fraction of 50%, placing the mixture into an oil bath with a mechanical stirrer, heating the mixture to 60 ℃ and stirring the mixture for 8 hours at 60r/min to form uniformly mixed viscous sol;

(3) Adding 30g of sodium carbonate into the viscous sol, continuing to stir for 2 hours at 60r/min, stopping stirring, increasing the temperature to 130 ℃, preserving heat for 4 hours, performing expansion reaction, and performing freeze drying to obtain a three-dimensional foam composite material;

(5) Crushing the mixture obtained in the step (4), stirring and mixing the crushed mixture with 3mol/L dilute hydrochloric acid according to the mass ratio of 1:20, soaking for 4 hours, centrifugally washing to be neutral, drying in a baking oven at 150 ℃ for 8 hours, and then taking the dried material to perform demagnetization and screening to obtain the anti-adsorptivity amorphous carbon negative electrode material.

In the amorphous carbon cathode material prepared by the embodiment, the mass of carbon particles accounts for 92% of the total mass of the amorphous carbon cathode material, the thickness of the foam carbon skeleton is 1.2 mu m, the pore diameter of macropores is 0.2-2 mu m, and the pore diameter of ultramicropores is less than 0.72nm; the total pore volume of the amorphous carbon anode material is 1.077cm ³/g, wherein the pore volume of the ultra-micropores accounts for 85.0% of the total pore volume, and the macropores account for 13.2% of the total pore volume; the median particle diameter (D50) of the amorphous carbon negative electrode material is 11.374 mu m, the specific surface area is 8.9m ²/g, and the powder contact angle of the amorphous carbon negative electrode material and water is 78 degrees (the powder contact angle between the amorphous carbon negative electrode material and cyclohexane is a 0-degree datum line).

Example 5

(1) Placing 800g of walnut shells in a box furnace under nitrogen atmosphere, heating to 300 ℃ at a heating rate of 1 ℃/min, carbonizing for 8 hours, cooling to 25 ℃ to obtain carbonized materials, crushing the carbonized materials by using a ball mill, and crushing the median particle size of the materials to 0.2 mu m to obtain carbon particles;

(2) Adding 100g of carbon particles into 890g of polyvinyl alcohol aqueous solution with the mass fraction of 90%, placing the mixture into an oil bath with a mechanical stirrer, heating the mixture to the temperature of 40 ℃ and stirring the mixture for 12 hours at the speed of 10r/min to form uniformly mixed viscous sol;

(3) Adding 80g of sodium carbonate into the viscous sol, continuing stirring for 0.5h at 10r/min, stopping stirring, raising the temperature to 60 ℃, preserving heat for 8h, performing expansion reaction, and performing freeze drying to obtain a three-dimensional foam composite material;

(4) Placing the three-dimensional foam composite material into a graphite crucible, placing the graphite crucible into a box-type furnace, introducing nitrogen protection gas, heating to 600 ℃ at a heating rate of 1 ℃/min, preserving heat for 6 hours, cooling to room temperature, and taking out to obtain a black mixture;

(5) Crushing the mixture obtained in the step (4), mixing with 2mol/L dilute hydrochloric acid according to a mass ratio of 1:2, soaking for 10 hours, centrifugally washing to be neutral, drying in a 50 ℃ oven for 48 hours, and then taking the dried material for carrying out demagnetization and screening to obtain the anti-adsorptivity amorphous carbon negative electrode material.

In the amorphous carbon cathode material prepared by the embodiment, the mass of carbon particles accounts for 70.1% of the total mass of the amorphous carbon cathode material, the thickness of the foam carbon skeleton is 1.5 mu m, the pore diameter of macropores is 0.3-2 mu m, and the pore diameter of ultramicropores is less than 0.54nm; the total pore volume of the amorphous carbon anode material is 2.044cm ³/g, wherein the pore volume of the ultra-micropores accounts for 28.9% of the total pore volume, and the macropores account for 70.1% of the total pore volume; the median particle diameter (D50) of the amorphous carbon negative electrode material is 8.132 mu m, the specific surface area is 50.1m ²/g, and the powder contact angle of the amorphous carbon negative electrode material and water is 47 degrees (the powder contact angle between the amorphous carbon negative electrode material and cyclohexane is a 0-degree datum line).

Example 6

(1) Placing 900g of coconut shells in a box furnace under nitrogen atmosphere, heating to 850 ℃ at a heating rate of 10 ℃/min, carbonizing for 0.5h, cooling to 25 ℃ to obtain carbonized materials, crushing the carbonized materials by using a ball mill, and crushing the medium particle size of the materials to 3.0 mu m to obtain carbon particles;

(2) Adding 100g of carbon particles into 500g of 10% polyvinyl alcohol aqueous solution by mass fraction, placing in an oil bath with a mechanical stirrer, heating to 100 ℃ and stirring for 1h at 90r/min to form uniformly mixed viscous sol;

(3) Adding 2g of sodium carbonate into the viscous sol, continuing stirring for 2 hours at 90r/min, stopping stirring, raising the temperature to 300 ℃, preserving heat for 0.5 hour, performing expansion reaction, and performing freeze drying to obtain a three-dimensional foam composite material;

(4) Placing the three-dimensional foam composite material into a graphite crucible, placing the graphite crucible into a box-type furnace, introducing nitrogen protection gas, heating to 1500 ℃ at a heating rate of 30 ℃/min, preserving heat for 0.5h, cooling to room temperature, and taking out to obtain a black mixture;

(5) Crushing the mixture obtained in the step (4), mixing with 5mol/L dilute hydrochloric acid according to a mass ratio of 1:50, soaking for 0.5h, centrifugally washing to be neutral, drying in a 200 ℃ oven for 5h, and then taking the dried material for demagnetizing and screening to obtain the anti-adsorptivity amorphous carbon negative electrode material.

In the amorphous carbon cathode material prepared by the embodiment, the mass of carbon particles accounts for 85% of the total mass of the amorphous carbon cathode material, the thickness of the foam carbon skeleton is 0.5 mu m, the pore diameter of macropores is 0.2-1 mu m, and the pore diameter of ultramicropores is less than 0.49nm; the total pore volume of the amorphous carbon anode material is 0.532cm ³/g, wherein the pore volume of the ultra-micropores accounts for 84.3% of the total pore volume, and the macropores account for 15.4% of the total pore volume; the median particle diameter (D50) of the amorphous carbon negative electrode material is 39.873 mu m, the specific surface area is 1.04m ²/g, and the powder contact angle of the amorphous carbon negative electrode material and water is 85 degrees (the powder contact angle between the amorphous carbon negative electrode material and cyclohexane is a 0-degree datum line).

Example 7

This example the starting materials and operating conditions for each step were the same as in example 1, except that only 1g of sodium bicarbonate was added in step (3).

The amorphous carbon cathode material prepared by the embodiment comprises a foam carbon skeleton and carbon particles embedded in the foam carbon skeleton, wherein the surface of the amorphous carbon cathode material only comprises a small number of macropores and micropores.

In the amorphous carbon cathode material prepared by the embodiment, the mass of carbon particles accounts for 82% of the total mass of the amorphous carbon cathode material, the thickness of the foam carbon skeleton is 2.3 μm, the pore diameter of macropores is 0.1-1 μm, and the pore diameter of ultramicropores is less than 0.42nm; the total pore volume of the amorphous carbon anode material is 0.132cm ³/g, wherein the pore volume of the ultra-micropores accounts for 98.3% of the total pore volume, and the macropores account for 1.3% of the total pore volume; the median particle diameter (D50) of the amorphous carbon negative electrode material is 38.735 mu m, the specific surface area is 3.6m ²/g, and the powder contact angle of the amorphous carbon negative electrode material and water is 67 degrees (the powder contact angle between the amorphous carbon negative electrode material and cyclohexane is a 0-degree datum line).

Example 8

This example the starting materials and operating conditions for each step were the same as in example 1, except that 90g of sodium bicarbonate was added in step (3).

The amorphous carbon anode material prepared by the embodiment comprises a carbon coating layer with a porous structure and a carbon particle inner core, wherein the surface of the amorphous carbon anode material comprises micropores with the diameter of less than 2nm (comprising super micropores with the diameter of less than 1 nm), mesopores with the diameter of 2-5 nm and macropores, and the proportion of macropores is very small.

In the amorphous carbon cathode material prepared by the embodiment, the mass of carbon particles accounts for 96% of the total mass of the amorphous carbon cathode material, the thickness of the coating layer is 0.3 mu m, the pore diameter of the macropores is 0.2-3 mu m, and the pore diameters of micropores are mainly distributed at 0.3-5.0nm (comprising ultra micropores); the total pore volume of the amorphous carbon anode material is 0.527cm ³/g, wherein the pore volume of micropores with the diameter of <2nm accounts for 63.4% of the total pore volume, and the macropores account for 1.9% of the total pore volume; the median particle diameter (D50) of the amorphous carbon negative electrode material is 39.453 mu m, the specific surface area is 86m ²/g, and the powder contact angle of the amorphous carbon negative electrode material and water is 48 degrees (the powder contact angle between the amorphous carbon negative electrode material and cyclohexane is a 0-degree datum line).

Comparative example 1

The specific preparation method of this comparative example was as described in example 1, except that the operations of steps (2) and (3) were not performed, i.e., gel polymerization was performed without adding an organic complex and expansion and etching pore-forming were performed without adding a curing expanding agent.

The results of the electrochemical test and the adsorption performance decay test of the hard carbon anode material prepared in the comparative example are shown in table 1.

Comparative example 2

The specific preparation method of this comparative example was as described in example 1, except that the operation of step (3) was not performed, i.e., the gel polymerization reaction was performed by adding the organic complex but the swelling and etching pore-forming were performed by not adding the curing swelling agent.

Performance test method

The negative electrode materials prepared in each example and comparative example were assembled into button cells with the negative electrode material Super-P cmc=96.5:1.5:2 as the working electrode and the lithium sheet as the positive electrode, and the first capacity was tested with a blue battery test system. In addition, the anode materials prepared in each example and comparative example were prepared into a wound soft pack battery, the mix ratio of the anode coating was determined according to the anode material CMC: SBR (styrene butadiene rubber) =96.5:1.5:2, liFePO ₄ was used as the cathode material, according to the cathode material CMC: sbr=97.3:1.0:1.7 as the cathode material, 1mol/L LiPF6/ec+dmc+emc (v/v=1:1:1) electrolyte and Celgard2400 separator, the assembled 18650 battery,

The first reversible capacity and first coulombic efficiency were tested with a 0.1C current charge and a 0.1C current discharge. And samples of the negative electrode materials of each example and comparative example were placed in air for 30 days, and the first reversible capacity and first coulombic efficiency after 30 days of placement were tested as described above.

Charging with 5C current, discharging with 5C current, and testing capacity retention rate after 3000 times.

The results of the above tests are shown in Table 1

TABLE 1

From the above examples and comparative examples, examples 1 to 6 were prepared into a three-dimensional foam type hierarchical pore amorphous carbon anode material by polymerization at low temperature and high temperature sintering etching by adding a curing expanding agent through a sol-gel auxiliary process during the preparation process. The amorphous carbon cathode materials prepared in examples 1-6 show excellent electrochemical properties in terms of primary reversible capacity, high-rate long-cycle capacity retention rate and the like, and the surface of the material has a lotus-leaf-developed ultra-microporous rough structure which prevents impurity gases in air from entering the material structure, so that the capacity and the primary effect of the material are hardly attenuated after the material is placed in the air.

In example 7, the addition amount of the curing expanding agent was too small, resulting in insufficient crosslinking degree and incomplete curing, and at the same time, the decomposition of the curing expanding agent produced less gas, and only a small amount of porous foam structure was formed.

In example 8, the addition amount of the curing expanding agent is too large, a large amount of gas is generated by decomposition of the curing expanding agent in the curing reaction process, a rich macroporous structure is formed, the inner wall is thinned, and the product after decomposition of the curing expanding agent is further etched at high temperature, so that a part of porous foam structure collapses.

In comparative example 1, no organic complex is added for gel polymerization reaction, no curing expanding agent is added for expansion and etching pore formation, no ultramicropore coating layer is arranged on the surface of the material, the material is placed in the air for 30 days, moisture in the air is adsorbed to bond with microcrystal gaps of a carbon layer, irreversible active sites are increased, impurity gas is adsorbed, the existing active sites are occupied, and the reversible capacity and the initial effect are reduced.

In comparative example 2, the gel cannot be crosslinked and cured to form a foam structure without adding a curing expanding agent for expansion and pore-forming by etching.

The applicant states that the detailed process equipment and process flows of the present invention are described by the above examples, but the present invention is not limited to, i.e., does not mean that the present invention must be practiced in dependence upon, the above detailed process equipment and process flows. It should be apparent to those skilled in the art that any modification of the present invention, equivalent substitution of raw materials for the product of the present invention, addition of auxiliary components, selection of specific modes, etc., falls within the scope of the present invention and the scope of disclosure.

Claims

1. The amorphous carbon cathode material is characterized by comprising a foam carbon skeleton and carbon particles embedded in the foam carbon skeleton, wherein the surface of the amorphous carbon cathode material comprises macropores and micropores;

the amorphous carbon anode material is of an integrated self-supporting structure and has a three-dimensional hierarchical pore structure and a rough structure;

the aperture of the ultra-micropore is 0-1.0nm and does not comprise 0; the pore diameter of the macropores is 0.2-3 mu m;

The macropores are connected with each other and the macropores and the ultramicropores are connected with each other.

2. The amorphous carbon negative electrode material according to claim 1, wherein the mass of the carbon particles is 70-98% of the total mass of the amorphous carbon negative electrode material.

3. The amorphous carbon negative electrode material according to claim 2, wherein the mass of the carbon particles is 80-95% of the total mass of the amorphous carbon negative electrode material.

4. The amorphous carbon negative electrode material according to claim 1, wherein the foam carbon skeleton has a thickness of 0-1.5 μm and does not contain 0.

5. The amorphous carbon negative electrode material according to claim 4, wherein the pore size of the ultra-micropores is 0-0.6nm and does not include 0.

6. The amorphous carbon anode material according to claim 1, wherein the amorphous carbon anode material has a total pore volume of 0.5-2.0 cm ³/g.

7. The amorphous carbon negative electrode material according to claim 6, wherein the pore volume of the ultra-micropores in the amorphous carbon negative electrode material is 30-85% of the total pore volume.

8. The amorphous carbon negative electrode material according to claim 6, wherein the pore volume of macropores in the amorphous carbon negative electrode material is 13-70% of the total pore volume.

9. The amorphous carbon negative electrode material according to claim 1, wherein the amorphous carbon negative electrode material has a median particle diameter of 8.0-40.0 μm.

10. The amorphous carbon negative electrode material according to claim 9, wherein the amorphous carbon negative electrode material has a median particle diameter of 15.0-30.0 μm.

11. The amorphous carbon negative electrode material according to claim 1, wherein the carbon particles have a median particle diameter of 0.2-3.0 μm.

12. The amorphous carbon negative electrode material according to claim 11, wherein the carbon particles have a median particle diameter of 0.5-2.0 μm.

13. The amorphous carbon negative electrode material according to claim 1, wherein the amorphous carbon negative electrode material has a specific surface area of 1-50 m ²/g.

14. The amorphous carbon negative electrode material according to claim 13, wherein the amorphous carbon negative electrode material has a specific surface area of 1-35m ²/g.

15. The amorphous carbon negative electrode material according to claim 1, wherein the powder contact angle of the amorphous carbon negative electrode material with water is 40-85 °.

16. A method for preparing an amorphous carbon negative electrode material according to any one of claims 1 to 15, comprising the steps of:

(1) Reacting carbon particles with an organic complex to obtain a sol;

(3) Sintering the composite material in the step (2) to obtain the amorphous carbon anode material;

The curing expanding agent in the step (2) comprises any one or a combination of at least two of sodium bicarbonate, sodium carbonate, sodium oxalate or calcium carbonate.

17. The process according to claim 16, wherein the carbon particles of step (1) have a median particle diameter of 0.2 to 3.0 μm.

18. The process according to claim 17, wherein the carbon particles of step (1) have a median particle diameter of 0.5 to 2.0 μm.

19. The method of claim 16, wherein the mass ratio of carbon particles to organic complex in step (1) is 1 (0.5-8).

20. The method of claim 19, wherein the mass ratio of carbon particles to organic complex in step (1) is 1 (1-6).

21. The method of claim 16, wherein the reacting carbon particles with the organic complex of step (1) comprises: adding carbon particles into the solution of the organic complex, and heating for reaction to obtain the sol.

22. The method according to claim 21, wherein the mass fraction of the organic complex in the solution of the organic complex is 10 to 90%.

23. The method according to claim 22, wherein the mass fraction of the organic complex in the solution of the organic complex is 40-70%.

24. The method of claim 16, wherein the organic complex comprises any one or a combination of at least two of sucrose, starch, gelatin, a thermoplastic phenolic resin, polypyrrole, polyaniline, or polyvinyl alcohol.

25. The method of claim 16, wherein the solvent comprises any one or a combination of at least two of water, ether, alcohol, ketone, and tetrahydrofuran.

26. The process of claim 21, wherein the heating reaction is carried out at a reaction temperature of 40-100 ℃.

27. The method according to claim 21, wherein the reaction time of the heating reaction is 1 to 12 hours.

28. The method of claim 21, wherein the heating is accompanied by stirring.

29. The method of claim 21, wherein the heating is performed with an oil bath.

30. The method of claim 28, wherein the stirring is performed at a stirring rate of 10-90r/min.

31. The method of claim 30, wherein the stirring is performed at a stirring rate of 30-60r/min.

32. The method of claim 16, wherein the mass ratio of the curing expanding agent to the carbon particles in the step (2) is (0.02-0.8): 1.

33. The method of claim 32, wherein the mass ratio of the curing expanding agent to the carbon particles in step (2) is (0.05-0.5): 1.

34. The method of claim 16, wherein the reacting of step (2) comprises: and (3) heating and curing the expanding agent, mixing, stopping the mixing operation, performing heating reaction, and drying after the reaction to obtain the composite material.

35. The method of claim 34, wherein the mixing is by stirring.

36. The method of claim 35, wherein the stirring rate of the stirring and mixing is 10-90 r/min.

37. The method of claim 36, wherein the stirring rate of the stirring and mixing is 30-60 r/min.

38. The method of claim 34, wherein the mixing is for a period of 0.5 to 3 hours.

39. The process of claim 34 wherein the heating reaction is carried out at a temperature of from 60 ℃ to 300 ℃.

40. The method of claim 34, wherein the heating reaction is carried out for a reaction time of 0.5 to 10 hours.

41. The method of claim 34, wherein the drying is cool drying or supercritical drying.

42. The method of claim 16, wherein the sintering of step (3) is performed in a protective atmosphere.

43. The method of claim 42, wherein the protective atmosphere comprises any one or a combination of at least two of a nitrogen atmosphere, a helium atmosphere, a neon atmosphere, an argon atmosphere, or a xenon atmosphere.

44. The method of claim 16, wherein the sintering in step (3) is performed at a temperature of 600-1500 ℃.

45. The method of claim 16, wherein the sintering time in step (3) is 0.5 to 6 hours.

46. The method of claim 16, wherein the sintering in step (3) is at a rate of 1-30 ℃/min.

47. The method of claim 16, wherein the sintering reactor of step (3) comprises any one or a combination of at least two of a vacuum furnace, a box furnace, a tube furnace, a roller kiln, a pusher kiln, a microwave pyrolysis furnace, or an ultraviolet pyrolysis furnace.

48. The method of manufacturing according to claim 16, wherein step (3) further comprises: cooling to 15-35 deg.c after sintering.

49. The method of manufacturing according to claim 16, wherein step (3) further comprises: and purifying the product obtained after sintering.

50. The method of claim 49, wherein the purifying comprises: and (3) stirring and mixing the sintered product with acid, carrying out suction filtration, washing the obtained solid with water to be neutral, centrifuging and drying, and carrying out demagnetizing and screening on the dried product to obtain the amorphous carbon anode material.

51. The method of claim 50, wherein the mass ratio of the sintered product to the acid is 1:2-1:50.

52. The method of claim 51, wherein the mass ratio of the sintered product to the acid is 1:5-1:20.

53. The method of claim 50, wherein the acid comprises any one or a combination of at least two of hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, boric acid, or oxalic acid.

54. The process of claim 50 wherein the concentration of the acid is 1-5 mol/L.

55. The process of claim 50 wherein the stirring is carried out for a period of time ranging from 0.5 to 10 hours.

56. The method of claim 50, wherein the centrifugation time is 0.5 to 8 hours.

57. The method of claim 56, wherein said centrifugation is for a period of 1.5 to 5 hours.

58. The process of claim 50, wherein the drying is performed in a vacuum oven, a forced air oven, a box furnace, a rotary kiln, or a twin cone dryer.

59. The process of claim 50 wherein the drying temperature is 50-200 ℃.

60. The process of claim 59 wherein the drying temperature is 80-150 ℃.

61. The process of claim 50 wherein the drying time is from 5 to 48 hours.

62. The method of claim 18, wherein the method of preparing carbon particles of step (1) comprises: carbonizing the carbon precursor in a protective atmosphere to obtain the carbon particles.

63. The method of claim 62, wherein the protective atmosphere comprises any one or a combination of at least two of a nitrogen atmosphere, a helium atmosphere, a neon atmosphere, an argon atmosphere, or a xenon atmosphere.

64. The method of claim 62, wherein the carbon precursor comprises any one or a combination of at least two of biomass, resin, pitch, or coke.

65. The method of claim 64, wherein the biomass comprises any one or a combination of at least two of coconut shell, apricot shell, fruit shell, or walnut shell.

66. The method of claim 64, wherein the resin comprises any one or a combination of at least two of a furfural resin, a phenolic resin, a melamine formaldehyde resin, an epoxy resin, an unsaturated polyester, a vinyl ester, a bismaleimide resin, a polyimide resin, polyethylene, polyvinyl chloride, polystyrene, polypropylene, or an acrylonitrile-styrene-butadiene copolymer.

67. The method of claim 64, wherein the bitumen comprises any one or a combination of at least two of coal tar pitch, shale pitch, or petroleum pitch.

68. The method of claim 64, wherein the char comprises any one or a combination of at least two of coal char, petroleum char, or mesophase carbon microbeads.

69. The method of claim 62, wherein the carbonization temperature is 300-850 ℃.

70. The method of claim 62, wherein the carbonization time is 0.5 to 8 hours.

71. The method of claim 62, wherein the carbonization is at a ramp rate of 1-10 ℃/min.

72. The method of claim 62, wherein the method of producing carbon particles further comprises: crushing and pulverizing the carbonized product.

73. The method of preparation according to claim 16, characterized in that the method comprises the steps of:

(4) Heating the composite material in the step (3) to 600-1500 ℃ at a heating rate of 1-15 ℃/min under protective atmosphere, sintering for 0.5-6h, cooling to 15-35 ℃ after sintering, stirring and mixing the sintered product with acid with the concentration of 1-5 mol/L for 0.5-10h at a mass ratio of 1:5-1:20, carrying out suction filtration, washing the obtained solid with water to be neutral, centrifuging for 1.5-5h, drying for 5-48h at 80-150 ℃, and carrying out demagnetizing and screening on the dried product to obtain the amorphous carbon anode material.

74. Use of an amorphous carbon negative electrode material according to any one of claims 1-15, wherein the amorphous carbon negative electrode material is used in a lithium ion battery, a sodium ion battery or a supercapacitor.