CN111146409B - Negative active material, method for preparing same, and secondary battery - Google Patents
Negative active material, method for preparing same, and secondary battery Download PDFInfo
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Abstract
本发明涉及一种负极活性材料、其制备方法及二次电池。具体地，本发明提供了一种负极活性材料，包括核及包覆其表面至少一部分的包覆层，所述核为SiOx(0＜x≤2)，所述包覆层包含钛元素，且所述负极活性材料在XRD测试谱图中同时存在TiO相和Ti5Si3相的峰。与传统的氧化物包覆硅基负极材料不同的是，本发明涉及的负极活性材料具有良好的导电性，其表面的氧化物包覆层具有良好的致密性和稳定性，从而极大地提升了使用该负极材料的电池的首次库伦效率和循环性能。
The present invention relates to a negative electrode active material, a preparation method thereof and a secondary battery. Specifically, the present invention provides a negative electrode active material, comprising a core and a coating layer covering at least a part of its surface, wherein the core is SiOx (0<x≤2), the coating layer contains titanium element, and The negative electrode active material has peaks of the TiO phase and the Ti 5 Si 3 phase simultaneously in the XRD test spectrum. Different from the traditional oxide-coated silicon-based negative electrode material, the negative electrode active material involved in the present invention has good electrical conductivity, and the oxide coating layer on its surface has good compactness and stability, thereby greatly improving the First Coulombic efficiency and cycle performance of batteries using this anode material.
Description
Technical Field
The invention belongs to the technical field of electrochemistry, and particularly relates to a negative active material, a preparation method thereof and a related secondary battery.
Background
With the miniaturization, weight reduction and multi-functionalization of portable electronic communication equipment or tools and the commercialization of electric vehicles, lithium ion batteries using graphite as a negative electrode have been unable to meet the actual demands of people, and the development of a lithium ion battery negative electrode material with high capacity has been the focus of attention in the industry.
Silicon metal has a gram capacity more than ten times higher than that of graphite and a lower lithium intercalation potential, and thus, once becomes a hot spot of research. The large volume expansion (300%) of pure silicon material during lithium intercalation limits its direct application in lithium ion batteries. In order to fully utilize the advantage of high capacity of silicon materials and solve the disadvantage of large expansion, silicon monoxide (SiO) materials are produced. The gram capacity of the SiO material is about 2600mAh/g, which is 7 times of that of graphite, but the volume expansion generated in the lithium intercalation process is reduced to 2/3 of pure silicon material, so that the SiO material becomes a lithium ion battery negative electrode material which is widely applied at present.
However, practical application of SiO also faces some difficulties. In order to improve the stability of the SiO material and improve the cycle performance of the lithium ion battery, the most used improvement scheme at present is to coat the surface of SiO particles to isolate the direct contact between the surface of the SiO particles and electrolyte, so that the material is protected from being damaged. At present, most of the SiO surface coating materials studied include carbon coating, metal coating, oxide coating and the like. However, in order to meet the actual industrial requirements, the conventional surface-coated SiO negative electrode material still needs to be further improved in terms of material stability, battery electrical properties, and the like.
Disclosure of Invention
An object of the present invention is to provide a negative active material having good stability and electrical properties, and a corresponding battery negative electrode sheet and a secondary battery.
In order to achieve the above object, a first aspect of the present invention provides a negative active material, including a core and a coating layer covering at least a portion of a surface of the core, wherein the core is a silicon-based material SiOx (x is greater than 0 and less than or equal to 2), the coating layer includes titanium, and the negative active material has a TiO phase and Ti phase in an XRD test spectrum5Si3Peak of phase.
In a second aspect, the present invention provides a method of preparing the anode active material according to the first aspect of the present invention.
In a third aspect, the present invention provides a secondary battery comprising a positive electrode sheet, a negative electrode sheet, a separator and an electrolyte, wherein the negative electrode sheet comprises the negative active material according to the first aspect of the present invention.
The cathode active material provided by the invention is of a core-shell structure, the core is a Si-based active material, the surface of the core is provided with a coating layer containing titanium, and the cathode active material simultaneously contains a TiO phase and Ti5Si3Make a bookThe cathode active material has good conductivity, and the coating layer on the surface of the cathode active material also has good compactness and stability, so that the first coulombic efficiency and the cycle performance of a battery using the cathode active material are greatly improved.
Drawings
The negative electrode active material and the secondary battery of the present invention and their advantageous effects are described in detail below with reference to the accompanying drawings and the detailed description.
Fig. 1 is an XRD spectrum of a negative active material according to example 1 of the present invention.
Fig. 2 is an XRD spectrum of the negative active material of comparative example 1 according to the present invention.
Detailed Description
The negative electrode active material and the secondary battery according to the present invention are described in detail below.
First, a negative active material according to a first aspect of the present invention is described, which includes a core and a coating layer coating at least a part of a surface thereof, the core being SiOx (0 < x.ltoreq.2), the coating layer including titanium, and the negative active material having both a TiO phase and Ti in an XRD test pattern5Si3Peak of phase.
The inventors have found through extensive studies that, when a silicon-based core (SiOx) of a negative electrode active material is coated with Ti, if a TiO phase and Ti are present together5Si3Phase, the stability of the anode material and the first coulombic efficiency and cycle performance of a battery using the anode material are greatly improved.
The silicon-based material belongs to a semiconductor material, so that the conductivity of the silicon-based material is poor, and when the silicon-based material is used in a negative electrode of a secondary battery, the battery is often polarized greatly in the charging and discharging process, and the capacity exertion and the cycle performance are further influenced. The invention generates TiO phase and Ti by coating the silicon-based material5Si3Compared with silicon-based materials, the material has better conductivity, wherein Ti5Si3The phase is used as a Si-Ti intermediate alloy phase and particularly has excellent conductivity, so that the conductivity of the negative electrode active material is greatly improved, and the cycle performance of the negative electrode active material is further improved.
To form a TiO phase and Ti5Si3The phase, preferably, forms a surface coating layer of the anode active material by in-situ reaction. The main reaction mechanism is as follows: the metal titanium powder is contacted with the SiOx, and the in-situ exchange reaction is carried out on the surface of the SiOx to generate Si and TiO; then the unreacted Ti on the particle surface reacts with the generated Si to generate Ti5Si3. In order to achieve the above object, the material may be prepared, for example, by a solid-phase reaction method comprising the steps of:
1) mixing a silicon-based material SiOx (x is more than 0 and less than or equal to 2) with a titanium source (metal titanium), and carrying out ball milling to obtain mixed powder;
2) putting the mixed powder obtained in the step 1) into an atmosphere furnace, performing high-temperature synthesis in an inert non-oxidizing atmosphere, and preserving heat for a certain time to obtain the negative active material.
The following parameters in the above-described preparation method affect the TiO phase and Ti in the negative active material5Si3Phase formation: the addition amount of a titanium source and the heat preservation time during high-temperature synthesis. Only when the addition amount of titanium reaches a certain value, there will be Ti5Si3And when the content of titanium is too high, the capacity loss of the active material is serious, and the active material has no practical application value. Too short incubation time during synthesis can result in incomplete solid phase reaction and influence on the formation of two phases. Therefore, the amount of the titanium element in the titanium source in the step 1) is preferably 2.5 to 30 percent, preferably 3 to 20 percent of the mass of the silicon-based material SiOx; the high-temperature synthesis temperature in the step 2) is 700-1500 ℃, and preferably 900-1200 ℃; the heat preservation time is 2 to 8 hours, preferably 3.5 to 6 hours.
In addition, the ball milling time in the step 1) is preferably 3 to 10 hours, and preferably 5 to 8 hours.
Further, preferably, the inert non-oxidizing atmosphere in step 2) is provided by at least one of the following gases: nitrogen, argon, helium; in the high-temperature synthesis step, the temperature rise speed is 1-10 ℃/min, preferably 1-5 ℃/min.
The silicon-based material as the core of the negative electrode active material of the present invention is SiOx (0 < x.ltoreq.2), i.e., a silicon-oxygen compound such as SiO, SiO2Or mixed oxides, etc. Preferably, the core of the negative active material of the present invention is SiOx (0 < x < 2). Silicon oxides suitable as anode materials are commercially available. Any silicon-based material known in the art to be suitable as an anode active material may also be used, such as one or more of elemental silicon, a silicon-carbon composite, and a silicon alloy, which are suitably oxidized to obtain the desired silicon oxide.
The titanium source used to form the cladding layer is metallic titanium, preferably in powder form. Those skilled in the art will appreciate that small amounts of other beneficial elements may be doped into the titanium if desired. Thus, "metallic titanium" in the present invention should be interpreted broadly, i.e. it may cover titanium alloys or mixtures of metallic titanium with small amounts of other metals.
However, the anode active material of the present invention is not necessarily prepared using the above method. So long as a TiO phase and Ti can be formed in the anode active material5Si3Other preparation methods may also be used. For example, the silicon-based material and the titanium source may be suspended in a solvent to form a suspension or slurry, followed by filtration, drying, and heat treatment during which the titanium source and the silicon-based material react to form a TiO phase and Ti5Si3And (4) phase(s).
TiO phase and Ti in the negative active material5Si3The presence of phases can be characterized by XRD (X-ray diffraction) test patterns. The XRD test is preferably XRD using CuK α radiation source. The negative active material of the invention has TiO phase and Ti simultaneously existing in XRD test spectrogram5Si3Diffraction peaks of the phases. Preferably, the negative active material further includes a diffraction peak of an Si phase in an XRD test pattern.
The TiO phase generally has a diffraction peak corresponding to the TiO phase in at least one of the ranges of 2 θ 35 ° to 38 °, 2 θ 40 ° to 45 °, and 2 θ 60 ° to 65 °, and for example, contains a diffraction peak corresponding to the TiO phase in at least one of 2 θ about 37 °, 2 θ about 43 °, and 2 θ about 62 °.
The Si phase generally has a diffraction peak corresponding to the Si phase in at least one of ranges of 25 ° to 30 °, 45 ° to 50 °, and 55 ° to 60 °, and for example, contains a diffraction peak corresponding to the Si phase in at least one of 2 θ about 28 °, 2 θ about 47 °, and 2 θ about 56 °.
For Ti5Si3The phase usually has a structure corresponding to Ti in at least one of the ranges of 35 ° to 38 °, 40 ° to 41.5 °, and 42 ° to 45 ° of 2 θ5Si3Diffraction peaks of the phases, e.g. having a phase corresponding to Ti in at least one of about 37 ° 2 θ, about 41 ° 2 θ and about 43 ° 2 θ5Si3Diffraction peaks of the phases.
When the negative active material of the present invention is subjected to XRD spectrum measurement, the 2 θ value of the obtained diffraction peak may have a certain degree of error due to differences in measurement conditions and errors in the measuring instrument. In this specification, the word "about" preceding a 2 θ value is to be understood to mean said 2 θ ± 2 °, preferably said 2 θ ± 1.5 °, most preferably said 2 θ ± 1 °.
In a preferred embodiment, the ratio of the diffraction peak intensity of the Si phase at 25 ° to 30 ° to the diffraction peak intensity of the TiO phase at 40 ° to 45 ° to 2 θ is 0.1 to 3.
In a preferred embodiment, the intensity of the diffraction peak of the Si phase at 25 ° to 30 ° 2 θ and the intensity of the diffraction peak of the Ti phase at 40 ° to 41.5 ° 2 θ are the same5Si3The ratio of the intensities of the phase diffraction peaks is 0.3 to 3.
In a preferred embodiment of the present invention, the mass ratio of the titanium element in the negative electrode active material is 2.5% to 15%, preferably 5% to 10%.
Preferably, D of the anode active material V50 satisfies 2 μm < D V50 μm or less and 18 μm or less, preferably 5 μm or less, D V50≤15μm。DV50 is a particle diameter corresponding to 50% of the cumulative volume percentage of the negative electrode active material, i.e., a volume distribution median particle diameter.
Preferably, the anode active material has a specific surface area (BET) of 0.5m2G to 8m2(ii)/g; further preferably, the specific surface area of the anode active material is 0.8m2G to 5m2/g。
The coating layer thickness of the negative active material may be determined as needed. In a preferred embodiment of the present invention, the coating layer of the negative electrode active material has a thickness of 5nm to 180nm, preferably 15nm to 40 nm.
Preferably, the coating layer of the anode active material coats most or substantially all of the surface of the core. The coating layer of the anode active material preferably coats at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, at least 95% of the surface area of the core, most preferably coats at least 98% of the surface area of the core, as calculated by area ratio.
In a preferred embodiment of the present invention, the negative active material has a resistivity of 0.005 Ω -cm to 100 Ω -cm, preferably 0.01 Ω -cm to 70 Ω -cm, under a pressure of 20 MPa.
At D V50. When the thickness, BET, resistivity, and the like are within the above preferred ranges, the cell performance is further improved.
The negative electrode active material of the present invention can be used to prepare a negative electrode sheet using methods known in the art. Generally, a negative electrode active material, an optional conductive agent (such as carbon materials such as carbon black and metal particles), a binder (such as SBR), other optional additives (such as PTC thermistor materials) and the like are mixed together and dispersed in a solvent (such as deionized water), uniformly stirred and then uniformly coated on a negative electrode current collector, and dried to obtain a negative electrode sheet containing a negative electrode membrane. As the negative electrode current collector, a material such as a metal foil or a porous metal plate may be used. Copper foil is preferably used. When the negative pole piece is prepared, the negative current collector can be coated on two sides or one side.
In another aspect, the present invention further provides a secondary battery, including a positive electrode plate, a negative electrode plate, a separator and an electrolyte, wherein the negative electrode plate includes the negative active material according to the first aspect of the present invention. The construction and production method of the secondary battery of the present invention are known per se, except that the anode active material of the present invention is used. The anode active material of the present invention may be used alone, and may be mixed with other anode active materials commonly used in the art. For example, the negative active material that can be mixed with the negative active material of the present invention may be one or more of graphite material, soft carbon, hard carbon, carbon fiber, mesocarbon microbeads, other silicon-based materials, tin-based materials, and lithium titanate.
In general, a secondary battery mainly comprises a positive electrode plate, a negative electrode plate, a separator and an electrolyte, wherein ions move between the positive electrode and the negative electrode by taking the electrolyte as a medium, so as to realize charging and discharging of the battery. In order to avoid short circuit of the positive and negative electrodes, the positive and negative electrode plates need to be separated by a separation film. The secondary battery may be in the form of an aluminum case or a pouch battery, for example.
It should be noted that the secondary battery according to another aspect of the present application may be a lithium ion battery, a sodium ion battery, or any other battery using the negative electrode sheet according to the first aspect of the present invention. Besides the negative electrode plate according to the first aspect of the present invention, there is no particular limitation on other components of the battery, such as the positive electrode plate, the separator, the electrolyte, etc., and those skilled in the art can select the negative electrode plate according to actual needs.
For example, when the battery is a lithium ion battery:
the positive electrode plate generally includes a positive electrode current collector and a positive electrode diaphragm disposed on a surface of the positive electrode current collector and including a positive electrode active material, where the positive electrode active material may be selected from lithium cobalt oxide, lithium nickel oxide, lithium manganese oxide, lithium nickel cobalt aluminum oxide, transition metal phosphate, lithium iron phosphate, and the like, but the present application is not limited to these materials, and other conventionally known materials that may be used as a positive electrode active material of a lithium ion battery may also be used. These positive electrode active materials may be used alone or in combination of two or more. Preferably, the positive active material may be selected from LiCoO2、LiNiO2、LiMnO2、LiMn2O4、LiNi1/3Co1/3Mn1/3O2(NCM333)、LiNi0.5Co0.2Mn0.3O2(NCM523)、LiNi0.6Co0.2Mn0.2O2(NCM622)、LiNi0.8Co0.1Mn0.1O2(NCM811)、LiNi0.85Co0.15Al0.05O2、LiFePO4、LiMnPO4One or more of them. In other embodiments of the present invention, a metallic lithium sheet can also be used directly as a positive electrode sheet (typically used to make lithium button cells).
For example, when the battery is a sodium ion battery:
the positive electrode plate generally includes a positive electrode current collector and a positive electrode membrane disposed on a surface of the positive electrode current collector and including a positive active material selected from a sodium iron composite oxide (NaFeO)2) Sodium cobalt composite oxide (NaCoO)2) Sodium chromium composite oxide (NaCrO)2) Sodium manganese oxide (NaMnO)2) Sodium nickel composite oxide (NaNiO)2) Sodium nickel titanium composite oxide (NaNi)1/2Ti1/2O2) Sodium nickel manganese composite oxide (NaNi)1/2Mn1/2O2) Sodium-iron-manganese composite oxide (Na)2/3Fe1/ 3Mn2/3O2) Sodium nickel cobalt manganese complex oxide (NaNi)1/3Co1/3Mn1/3O2) Sodium iron phosphate compound (NaFePO)4) Sodium manganese phosphate compound (NaMnPO)4) Sodium cobalt phosphate compound (NaCoPO)4) A prussian blue-based material, a polyanion material (phosphate, fluorophosphate, pyrophosphate, sulfate), and the like, but the present application is not limited to these materials, and other conventionally known materials that can be used as a positive electrode active material of a sodium ion battery may be used. These positive electrode active materials may be used alone or in combination of two or more.
In the battery according to another aspect of the present invention, the specific types and compositions of the separator and the electrolyte are not particularly limited and may be selected according to actual requirements.
Specifically, the separator may be selected from the group consisting of a polyethylene film, a polypropylene film, a polyvinylidene fluoride film, and a multi-layer composite film thereof.
When the battery is a lithium ion battery, a nonaqueous electrolytic solution is generally used as an electrolyte. As the nonaqueous electrolytic solution, one dissolved in an organic solvent is generally usedA lithium salt solution. The lithium salt is, for example, LiClO4、LiPF6、LiBF4、LiAsF6、LiSbF6Etc. inorganic lithium salt, or LiCF3SO3、LiCF3CO2、Li2C2F4(SO3)2、LiN(CF3SO2)2、LiC(CF3SO2)3、LiCnF2n+1SO3(n is more than or equal to 2) and the like. Examples of the organic solvent used in the nonaqueous electrolytic solution include cyclic carbonates such as ethylene carbonate, propylene carbonate, butylene carbonate and vinylene carbonate, linear carbonates such as dimethyl carbonate, diethyl carbonate and methyl ethyl carbonate, linear esters such as methyl propionate, cyclic esters such as γ -butyrolactone, linear ethers such as dimethoxyethane, diethyl ether, diglyme and triglyme, cyclic ethers such as tetrahydrofuran and 2-methyltetrahydrofuran, nitriles such as acetonitrile and propionitrile, and mixtures of these solvents.
The structure and production method of the secondary battery of the present invention will be briefly described below by taking a lithium ion battery as an example.
Firstly, preparing a battery positive pole piece according to a conventional method in the field. The invention does not limit the positive active material used by the positive pole piece. In general, it is necessary to add a conductive agent (for example, a carbon material such as carbon black), a binder (for example, PVDF), and the like to the positive electrode active material. Other additives such as PTC thermistor materials and the like may also be added as necessary. The materials are usually mixed together and dispersed in a solvent (such as NMP), uniformly coated on a positive current collector after being uniformly stirred, and dried to obtain the positive pole piece. As the positive electrode current collector, a material such as a metal foil or a porous metal plate may be used. Preferably, aluminum foil is used.
Then, a negative electrode sheet was prepared as described above using the negative electrode active material of the present invention.
Finally, stacking the positive pole piece, the isolating membrane and the negative pole piece in sequence to enable the isolating membrane to be positioned between the positive pole piece and the negative pole piece to play an isolating role, and then winding to obtain a bare cell; and placing the bare cell in an outer packaging shell, drying, injecting electrolyte, and performing vacuum packaging, standing, formation, shaping and other processes to obtain the secondary battery.
Different from the traditional oxide-coated silicon-based negative electrode material, the negative electrode active material has good conductivity, and the coating layer on the surface of the negative electrode active material has good compactness and stability, so that the first coulombic efficiency and the cycle performance of a battery using the negative electrode material are greatly improved. Therefore, the method has very important significance in the fields of new energy automobiles and the like.
Unless otherwise specified, various parameters referred to in this specification have the common meaning known in the art and can be measured according to methods known in the art. For example, the test can be performed in accordance with the method given in the examples of the present invention. In addition, the preferred ranges and options for the various parameters given in the various preferred embodiments can be combined arbitrarily, and the various combinations thus obtained are considered to be within the scope of the disclosure.
The following examples are provided to further illustrate the advantageous effects of the present invention.
Examples
In order to make the objects, technical solutions and advantageous technical effects of the present invention more clear, the present invention is further described in detail below with reference to examples. However, it should be understood that the embodiments of the present invention are only for explaining the present invention and are not for limiting the present invention, and the embodiments of the present invention are not limited to the embodiments given in the specification. The examples were prepared under conventional conditions or conditions recommended by the material suppliers without specifying specific experimental conditions or operating conditions.
Preparation of button cell for testing
The batteries of the respective examples and comparative examples were prepared as follows:
1. preparing a positive pole piece: a round lithium plate was used.
2. Preparing a negative pole piece:
A. negative electrode active material
The negative active materials used in the respective examples and comparative examples were titanium-coated silicon-based materials prepared according to the following procedure:
1) mixing a silicon-based material and a titanium source in a certain proportion, and carrying out ball milling to obtain mixed powder;
2) putting the mixed powder obtained in the step 1) into an atmosphere furnace, and adding N2And carrying out high-temperature synthesis in the atmosphere, and preserving the heat for a certain time to obtain the silicon-based composite active material.
Wherein the silicon-based material (i.e., the core of the negative active material), the specific composition and relative proportions of the titanium source, and the operating parameters of step 2) are specified in table 1.
B. Negative pole piece
Fully dissolving 10 wt% of water-based carboxymethyl cellulose binder into water, and adding 10 wt% of carbon black conductive agent and 80 wt% of the prepared negative electrode active material to prepare uniformly dispersed slurry. The slurry is uniformly coated on the surface of the copper foil and then transferred to a vacuum drying oven for complete drying. And rolling the obtained pole piece, and then blanking to obtain a wafer with the size consistent with that of the lithium piece.
3. Preparing an electrolyte:
ethylene Carbonate (EC), Ethyl Methyl Carbonate (EMC) and diethyl carbonate (DEC) were mixed in a volume ratio of 1:1:1, and then a well-dried lithium salt LiPF was added6Dissolving the electrolyte into a mixed organic solvent according to the proportion of 1mol/L to prepare the electrolyte.
4. Preparing an isolating membrane:
12 micron polyethylene film is selected.
5. Assembling the battery:
and (3) stacking the positive pole piece, the isolating membrane and the negative pole piece in sequence to enable the isolating membrane to be positioned between the positive pole piece and the negative pole piece to play an isolating role, and adding the electrolyte to assemble the button cell.
Secondly, measuring the parameters of the negative active material and the negative pole piece
1) D of negative active materialV50：
Measuring the particle size distribution by using a laser diffraction particle size distribution measuring instrument (Malvern Mastersizer 3000) according to a particle size distribution laser diffraction method GB/T19077-2016 to obtain D V50。
2) XRD measurement: the test was carried out using an X-ray diffractometer (D500Siemens) using a copper target (λ ═ 0.154nm), with a scanning speed of 4 °/min and a CuK α source as the radiation source.
Third, testing the battery performance
1) Cycle performance test
The cells prepared in the examples and comparative examples were discharged to 5mV at 0.1C rate and charged to 1.5V at 0.1C rate at 25C and full charge discharge cycle tests were performed until the capacity of the lithium ion cell was less than 80% of the initial capacity and the number of cycles recorded.
2) First coulombic efficiency
The batteries prepared in examples and comparative examples were discharged to 5mV at a rate of 0.1C and charged to 1.5V at a rate of 0.1C at 25C, and full charge discharge tests were performed to obtain a ratio of charge capacity to discharge capacity as a first effect.
Fourth, test results of examples and comparative examples
The batteries of examples 1 to 9 and comparative examples 1 to 3 were prepared according to the above-described methods, respectively, and various performance parameters were measured, with the results of Table 1.
The phase states of the anode active materials of the respective examples and comparative examples, which are inferred from the XRD patterns, are given in table 1. Description figures 1 and 2 show XRD spectra of example 1 and comparative example 1, respectively, as an example.
FIG. 1 shows the XRD pattern of example 1, in which the TiO, Si and Ti phases can be seen5Si3The respective 2 θ values are as follows:
peak value corresponding to TiO: 36.65 °, 42.61 °, 61.80 °
Peak value corresponding to Si: 28.44 deg., 47.30 deg., 56.12 deg
Ti5Si3Corresponding peak value: 40.95 deg., 42.69 deg. and 36.87 deg
From the coulombic efficiency comparison of table 1, it can be seen that: only the negative active material contains TiO phase and Ti5Si3The corresponding battery has better coulombic efficiency. In contrast, comparative examples 1 to 3 contained only TiO phases and only TiO2Phase or only TiO phase and Si phase,coulomb efficiency is not ideal. In addition, the cycle performance test result shows that the negative active material contains TiO phase and Ti simultaneously5Si3The phase time can remarkably improve the cycle performance of the battery.
This indicates that: metal Ti and SiO are used as raw materials to form a titanium dioxide film containing TiO phase and Ti simultaneously under proper conditions5Si3When the phase titanium is coated on the silicon-based negative electrode material, the electrical property of the corresponding battery can be improved.
The XRD pattern of comparative example 1 is shown in FIG. 2, in which only the peaks corresponding to the TiO phase and Si are present. It can be seen from the data of comparative example 1 in Table 1 that, when metallic titanium is used as the titanium source, if the amount of the titanium source added is too small, all titanium participates in the reduction reaction to produce TiO and Si, and no titanium remains to be combined with Si to form Ti5Si3And (4) phase(s).
Comparative examples 2 and 3 show that TiO or TiO is used2Is a titanium source, Ti cannot be formed due to the absence of Ti simple substance5Si3And (4) phase(s).
Further experiments (results not shown) also confirmed that in an oxidizing atmosphere, Ti could not be formed due to oxidation of Ti5Si3And (4) phase(s).
It can be seen from the data of the examples and comparative examples that both TiO phase and Ti phase can be formed under appropriate conditions using metallic titanium and SiO as raw materials5Si3The phase (preferably, the phase also has a Si phase) titanium is coated on the silicon-based negative electrode material, so that the electric properties of the battery using the negative electrode material, such as the first coulombic efficiency, are greatly improved.
It should be further noted that, based on the disclosure and guidance in the above description, those skilled in the art to which the present invention pertains may make appropriate changes and modifications to the above-described embodiments. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed and described, but that various modifications and changes may be made thereto without departing from the scope of the invention as defined in the appended claims. Furthermore, although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.
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| CN114142015B (en) * | 2021-12-03 | 2024-07-16 | 珠海冠宇电池股份有限公司 | Negative electrode material and battery comprising same |
| CN118970143A (en) * | 2022-04-29 | 2024-11-15 | 宁德时代新能源科技股份有限公司 | Secondary battery, battery module, battery pack and power-consuming device |
| CN116093301A (en) * | 2023-01-14 | 2023-05-09 | 惠州锂威新能源科技有限公司 | Modified silicon-oxygen negative electrode material, preparation method thereof, and negative electrode sheet |
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| CN104538609A (en) * | 2014-12-23 | 2015-04-22 | 东莞市迈科科技有限公司 | A kind of negative electrode composite material for lithium ion battery and preparation method thereof |
| CN107706383A (en) * | 2017-09-21 | 2018-02-16 | 合肥国轩高科动力能源有限公司 | In-situ titanium-doped carbon-coated silicon oxide/graphite material and preparation method thereof |
| CN108352513A (en) * | 2015-11-10 | 2018-07-31 | 日产自动车株式会社 | Negative electrode active material for electrical and the electrical equipment for having used it |
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| KR102341406B1 (en) * | 2015-06-09 | 2021-12-21 | 삼성에스디아이 주식회사 | Composite for anode active material, anode including the composite, lithium secondary battery including the anode, and method of preparing the composite |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN108352513A (en) * | 2015-11-10 | 2018-07-31 | 日产自动车株式会社 | Negative electrode active material for electrical and the electrical equipment for having used it |
| CN107706383A (en) * | 2017-09-21 | 2018-02-16 | 合肥国轩高科动力能源有限公司 | In-situ titanium-doped carbon-coated silicon oxide/graphite material and preparation method thereof |
Non-Patent Citations (1)
| Title |
|---|
| "Mechanochemical synthesis and high-frequency induction heated consolidation of nanostructured Ti5Si3 and its mechanical properties";Wonbaek Kim 等;《Res Chem Intermed》;20120815;第39卷;第2339-2349页 * |
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