CN118099403B - All-solid-state composite silicon anode material and preparation method and application thereof - Google Patents

All-solid-state composite silicon anode material and preparation method and application thereof Download PDF

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CN118099403B
CN118099403B CN202410525210.6A CN202410525210A CN118099403B CN 118099403 B CN118099403 B CN 118099403B CN 202410525210 A CN202410525210 A CN 202410525210A CN 118099403 B CN118099403 B CN 118099403B
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silicon
solid
anode material
lithium
melting
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CN118099403A (en
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朱高龙
张恒通
谭铁宁
罗金敏
杜心宇
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Sichuan New Energy Vehicle Innovation Center Co Ltd
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Sichuan New Energy Vehicle Innovation Center Co Ltd
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    • H01M4/02—Electrodes composed of, or comprising, active material
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    • H—ELECTRICITY
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    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/05—Accumulators with non-aqueous electrolyte
    • H01M10/052—Li-accumulators
    • H01M10/0525—Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • H—ELECTRICITY
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    • H01M4/38—Selection of substances as active materials, active masses, active liquids of elements or alloys
    • H01M4/381—Alkaline or alkaline earth metals elements
    • H01M4/382—Lithium
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    • H01M4/36—Selection of substances as active materials, active masses, active liquids
    • H01M4/38—Selection of substances as active materials, active masses, active liquids of elements or alloys
    • H01M4/386—Silicon or alloys based on silicon
    • H—ELECTRICITY
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    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
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    • H01M4/58—Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
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    • H01M4/60—Selection of substances as active materials, active masses, active liquids of organic compounds
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Abstract

The invention discloses an all-solid-state composite silicon anode material, a preparation method and application thereof. The preparation method comprises the following steps: and (3) melting the mixture of the lithium source, the silicon-based material and the organic matters at a high temperature. The silicon-based composite anode material with the uniform porous structure is beneficial to the deintercalation of lithium without causing remarkable expansion of the structure, has good charge-discharge cycle performance, and has the effects of relieving the volume expansion of the material and enhancing the conductivity of the material, and carbon simple substances are dispersed on the surface and the inside of the anode material.

Description

All-solid-state composite silicon anode material and preparation method and application thereof
Technical Field
The invention relates to the technical field of lithium ion batteries, in particular to an all-solid-state composite silicon anode material, and a preparation method and application thereof.
Background
With the rapid development and continuous growth of new energy automobile industry in recent years, the energy density of the existing lithium ion battery system is gradually unable to meet the increasing energy demand, and the development of a battery system with high power, high capacity and high safety is urgent. In a power lithium ion battery, a negative electrode material plays a critical role in the energy density of the lithium ion battery.
The application of the lithium storage capacity of the graphite anode material of the commercial lithium ion battery reaches the theoretical value 372 mAh/g at present, and the development potential is not provided, so that the development of a novel anode material with high lithium storage capacity becomes the current hot research content. In order to pursue high energy density of solid-state lithium batteries, most of research is focused on lithium metal solid-state batteries, however, the problems of uncontrollable side reactions, dendrite growth and the like at the interface of lithium metal and solid electrolyte are difficult to solve. Therefore, people are increasingly directing their eyes to silicon anode solid-state batteries which are more stable and have a high specific capacity. Silicon is currently the material with the highest known lithium storage capacity (4200 mAh/g), the silicon negative electrode itself has no lithium dendrite problem, and the generation of silicon surface byproducts is also minimized due to the introduction of low-reactivity solid electrolyte, but the rapid decay of capacity is caused due to particle breakage and pulverization caused by huge volume change (> 300%) during charge and discharge, and the poor rate capability caused by low electronic conductivity (σ e<10-5S cm-1) and low lithium ion diffusion rate (D Li+：10-14~10-13cm2s-1) is limited to wide application.
To address these issues, various silicon negative electrode modification strategies (e.g., nanocrystallization, 3D structures, composite silicon negative electrodes, etc.) have been developed to improve the electrochemical performance of silicon-based negative electrode materials. Despite the great progress made in the laboratory in solving these problems, most silicon-containing cells in industry (where silicon anodes are made of silicon suboxide or Si-C composite materials) can only use very limited amounts of silicon, and high silicon systems still have a large volume expansion, greatly impeding the development of high energy density solid state cells. Therefore, there is a need to develop a negative electrode material that has small volume expansion, large capacity and can suppress lithium dendrites, which is advantageous for promoting the development of silicon-based solid-state batteries.
In view of this, the present invention has been made.
Disclosure of Invention
The invention aims to provide an all-solid-state composite silicon anode material, and a preparation method and application thereof, so as to solve the technical problems.
The invention is realized in the following way:
in a first aspect, the invention provides an all-solid-state composite silicon anode material, which comprises a framework material formed by lithium and silicon, wherein carbon and organic matters are coated on the framework material, and the all-solid-state composite silicon anode material has a porous structure.
In a second aspect, the invention also provides a preparation method of the all-solid-state composite silicon anode material, which comprises the following steps: and (3) melting the mixture of the lithium source, the silicon-based material and the organic matters at a high temperature.
Alternatively, the melting temperature is 500 ℃ to 1200 ℃, preferably 900 ℃ to 1100 ℃.
Optionally, preserving heat for 1-20 h at the melting temperature.
Optionally, the mass ratio of the lithium source, the silicon-based material and the organic matter is (15-45): (10-40): (30-60).
Optionally, the high-temperature melting is performed in an inert environment, and optionally, the melting atmosphere is an inert atmosphere, and the reaction vessel is made of inert materials.
Optionally, the lithium source is metallic lithium, and optionally, the metallic lithium is flake or powder.
Alternatively, the silicon-based material is selected from at least one of elemental silicon, silicon oxide, and silicon dioxide.
Optionally, the organic matter is selected from at least one of acrylonitrile copolymer, phenolic resin, epoxy resin, polyfurfuryl alcohol, polyvinyl alcohol and polyvinyl chloride. These organics can produce a uniform and dense carbon layer during pyrolysis. The carbon layer can effectively isolate the direct corrosion of the electrolyte to the silicon surface, and improve the chemical stability of the material. Meanwhile, the carbon layer improves the overall electronic conductivity of the composite material, and reduces the contact resistance between the silicon inside and the external circuit, thereby improving the charge transmission efficiency in the charge-discharge process. The organic matters have low cost, strong compatibility and easy mass production.
Optionally, the preparation method of the all-solid-state composite silicon anode material further comprises the steps of crushing the alloy compound obtained by high-temperature melting and then carrying out acid etching.
Optionally, washing and drying are carried out after the acid etching, and optionally, the drying mode is vacuum drying, and the drying temperature is 50-200 ℃.
Optionally, the acid to be acid etched is selected from at least one of hydrofluoric acid, hydrochloric acid, or nitric acid.
In a third aspect, the invention also provides an application of the all-solid-state composite silicon anode material in a solid-state battery.
The invention has the following beneficial effects: and part of organic matters are carbonized to generate carbon simple substances to coat silicon and lithium in a one-step high-temperature melting mode, and meanwhile, part of organic matters are stabilized on the frameworks of the lithium and the silicon to form the alloy compound of the lithium, the silicon-based material, the organic matters and the carbon simple substances. The porous structure of the all-solid-state composite silicon anode material is beneficial to the deintercalation of lithium without causing obvious expansion of the structure, carbon and organic matters can play a role in coating lithium and silicon, and are beneficial to inhibiting lithium dendrites, and simultaneously, carbon simple substances are dispersed on the surface and inside of the anode material, so that the mechanical stress is reduced, and the effect of relieving the volume expansion of the material and enhancing the conductivity of the material is also achieved.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are needed in the embodiments will be briefly described below, it being understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and other related drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
Fig. 1 is a scanning electron microscope image of an all-solid-state composite silicon anode material obtained in example 1 of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below. The specific conditions are not noted in the examples and are carried out according to conventional conditions or conditions recommended by the manufacturer. The reagents or apparatus used were conventional products commercially available without the manufacturer's attention.
The invention provides an all-solid-state composite silicon anode material, and a preparation method and application thereof.
Some embodiments of the invention provide an all-solid-state composite silicon anode material, which comprises a framework material formed by lithium and silicon, wherein carbon and organic matters are coated on the framework material, and the all-solid-state composite silicon anode material has a porous structure.
In this embodiment, the all-solid-state composite silicon anode material is an alloy compound of lithium, a silicon-based material, an organic matter and a carbon simple substance, the anode material mainly comprises a framework material formed by lithium and silicon, wherein carbon is uniformly dispersed in the inside and the outside of the all-solid-state composite silicon anode material, the uniform dispersion refers to a uniform state generated by reaction after raw materials are uniformly mixed in the process of generating the all-solid-state composite silicon anode material, the uniform dispersion is not particularly referred to in an ideal state, the framework material formed by lithium and silicon is also stably connected with the organic matter, and the organic matter and the carbon can stabilize an alloying structure of the anode material in circulation. The porous structure of the all-solid-state composite silicon anode material is favorable for the deintercalation of lithium without causing remarkable expansion of the structure, has good charge-discharge cycle performance, and simultaneously has the effects of relieving the volume expansion of the material and enhancing the conductivity of the material because carbon simple substances are dispersed on the surface and the inside of the anode material.
Some embodiments of the present invention also provide a method for preparing the above all-solid composite silicon anode material, which includes: and (3) melting the mixture of the lithium source, the silicon-based material and the organic matters at a high temperature.
Three raw materials are alloyed in a molten state by a high-temperature melting method, part of organic matters are carbonized into carbon simple substances, part of organic matters are stabilized on a framework formed by lithium and silicon, an alloying structure of the anode material is stabilized in a circulation mode, meanwhile, in the molten state, complex reactions occur among the raw materials, gas is generated in the carbonization process of the organic matters, and further, the formed alloy compound of the lithium, silicon-based material, the organic matters and the carbon simple substances has a porous structure.
In particular, in some embodiments, the lithium source includes, but is not limited to, metallic lithium, which may generally be in the form of flakes or powder.
In some embodiments, the silicon-based material includes, but is not limited to, at least one of elemental silicon, silicon oxide, and silicon dioxide. That is, the silicon-based material can be selected from any one of simple substance silicon, silicon oxide and silicon dioxide, or can be selected from two or three of the above materials, and the combination ratio is not limited.
In some embodiments, the organic matter includes, but is not limited to, at least one of acrylonitrile copolymer, phenolic resin, epoxy resin, polyfurfuryl alcohol, polyvinyl alcohol (PVA), and polyvinyl chloride (PVC). That is, the organic matter may be one of acrylonitrile copolymer, phenolic resin, epoxy resin, polyfurfuryl alcohol, polyvinyl alcohol and polyvinyl chloride alone, or two or more of these may be combined in a non-limited ratio. The organic material may be selected so long as it is a solid or liquid organic material that can be carbonized at the melting temperature.
Further, in the high temperature melting process, the melting temperature is selected to affect the performance of the composite anode material, that is, the temperature is too low, the carbonization degree is low, the reaction is insufficient, the pore structure is poor, the reaction is severe, the carbonization degree of the organic matters is difficult to control, and the like, so in some embodiments, the melting temperature is 500 ℃ to 1200 ℃, for example ,500℃、520℃、550℃、570℃、590℃、600℃、620℃、650℃、680℃、700℃、730℃、750℃、770℃、800℃、820℃、850℃、900℃、910℃、930℃、950℃、970℃、990℃、1000℃、1020℃、1050℃、1070℃、1090℃、1100℃、1120℃、1150℃ or 1200 ℃, and in some preferred embodiments, the melting temperature is 900 ℃ to 1100 ℃.
In some embodiments, the heat is preserved for 1h to 20h at the melting temperature, for example, the heat preservation time is 1h, 2h, 3h, 4h, 5h, 6h, 7h, 8h, 9h, 10h, 11h, 12h, 13h, 14h, 15h, 16h, 17h, 18h, 19h or 20h, etc., generally the higher the melting temperature is, the shorter the heat preservation time is.
In some embodiments, the mass ratio of the lithium source, the silicon-based material, and the organic matter is (15-45): (10-40): (30-60). For example, the mass ratio of lithium source, silicon-based material and organic matter is 15：40：55、15：20：30、15：30：40、15：35：50、20：40：55、20：30：50、20：20：30、30：20：40、30：30：40、30：40：55、30：35：50、40：40：55 or 40:25:50, etc. It should be noted that, the content of the organic matters is not too high or too low, and too high may cause the main structural material to be low, so as to affect the capacity, the cycle performance and the like of the obtained composite silicon anode material, and too low may cause the carbon simple substance generated by carbonization to be insufficient, the pore structure and the like, so as to affect the expansion performance of the composite silicon anode material.
In order to avoid the influence of the external environment on the high-temperature melting process, such as oxygen, etc., in some embodiments, the high-temperature melting is performed under an inert environment, specifically, the high-temperature melting is performed under an inert atmosphere, and the reaction vessel is made of an inert material, that is, the reaction vessel is resistant to high temperature and inert to lithium, silicon and organic matters, and does not undergo side reactions with these matters.
Further, the lithium source, the silicon-based material and the organic matter are melted in one step to form an alloy compound, the reaction process is relatively complex, and therefore, the generated pore structure is relatively uneven, and therefore, in order to obtain a composite silicon anode material with a better pore structure, in some embodiments, the preparation method of the all-solid-state composite silicon anode material further comprises crushing the obtained alloy compound and then performing acid etching. It should be noted that, after pulverizing the material, a sieving operation is generally required to obtain relatively uniform powder particles.
Washing and drying treatment are carried out after acid etching, specifically, water is added into the washing mode for centrifugal washing, and the drying mode is vacuum drying, wherein the drying temperature is 50-200 ℃. Further, the drying can be followed by crushing and sieving again to obtain a uniform porous composite silicon anode material.
In some embodiments, the acid to be etched is at least one selected from hydrofluoric acid, hydrochloric acid and nitric acid, i.e., any one selected from hydrofluoric acid, hydrochloric acid and nitric acid.
Further, some embodiments of the invention also provide application of the above all-solid-state composite silicon anode material in solid-state batteries. Namely, the negative electrode material of the solid-state battery is the all-solid-state composite silicon negative electrode material.
The features and capabilities of the present invention are described in further detail below in connection with the examples.
Example 1
The embodiment provides an all-solid-state composite silicon anode material, which specifically comprises the following steps:
Metal lithium sheet, simple substance silicon and epoxy resin are mixed according to the mass ratio of 15:40:55, melting at 1000 ℃ under inert atmosphere, and preserving heat for 10 hours to obtain the composite material. The composite material is crushed and sieved to obtain uniform powder particles with the particle size smaller than 10 mu m. The powder particles were put into hydrofluoric acid (4 wt%) for hydrofluoric acid etching for 2 hours, and then washed. Drying is carried out under vacuum inert atmosphere at 50 ℃. And then crushing and sieving to obtain the uniform porous composite silicon-based anode material.
Example 2
The embodiment provides an all-solid-state composite silicon anode material, which specifically comprises the following steps:
Mixing a metal lithium sheet, silicon dioxide and polyacrylonitrile-based carbon fiber according to a mass ratio of 45:10:45, and melting at 1200 ℃ in an inert atmosphere, and preserving heat for 1h to obtain the composite material. The composite material is crushed and sieved to obtain uniform powder particles with the particle size smaller than 10 mu m. The powder particles were put into hydrofluoric acid (4 wt%) for hydrofluoric acid etching for 2 hours, and then washed. Drying is carried out at 150 ℃ under vacuum inert atmosphere. And then crushing and sieving to obtain the uniform porous composite silicon-based anode material.
Example 3
The embodiment provides an all-solid-state composite silicon anode material, which specifically comprises the following steps:
mixing metal lithium powder, simple substance silicon and PVA according to a mass ratio of 30:40:30, melting at 800 ℃ under inert atmosphere, and preserving heat for 10 hours to obtain the composite material. The composite material is crushed and sieved to obtain uniform powder particles with the particle size smaller than 10 mu m. The powder particles were put into hydrochloric acid (4 wt%) for hydrochloric acid etching for 2 hours, and then washed. Drying is carried out at 100 ℃ under vacuum inert atmosphere. And then crushing and sieving to obtain the uniform porous composite silicon-based anode material.
Example 4
The embodiment provides an all-solid-state composite silicon anode material, which specifically comprises the following steps:
Mixing the metal lithium sheet, the silicon oxide and the polyvinyl chloride according to the mass ratio of 20:20:60, and melting at 1000 ℃ under inert atmosphere, and preserving heat for 15 hours to obtain the composite material. The composite material is crushed and sieved to obtain uniform powder particles with the particle size smaller than 10 mu m. The powder particles were put into nitric acid (4 wt%) for nitric acid etching for 2 hours, and then washed. Drying is carried out under vacuum inert atmosphere at 200 ℃. And then crushing and sieving to obtain the uniform porous composite silicon-based anode material.
Example 5
Metal lithium sheet, simple substance silicon and epoxy resin are mixed according to the mass ratio of 15:40:55, melting at 1050 ℃ under inert atmosphere, and preserving heat for 8 hours to obtain the composite material. The composite material is crushed and sieved to obtain uniform powder particles with the particle size smaller than 10 mu m. The powder particles were put into hydrofluoric acid (4 wt%) for hydrofluoric acid etching for 2 hours, and then washed. Drying is carried out under vacuum inert atmosphere at 50 ℃. And then crushing and sieving to obtain the uniform porous composite silicon-based anode material.
Example 6
Metal lithium sheet, simple substance silicon and epoxy resin are mixed according to the mass ratio of 15:40:55, melting at 950 ℃ in an inert atmosphere, and preserving the heat for 12 hours to obtain the composite material. The composite material is crushed and sieved to obtain uniform powder particles with the particle size smaller than 10 mu m. The powder particles were put into hydrofluoric acid (4 wt%) for hydrofluoric acid etching for 2 hours, and then washed. Drying is carried out under vacuum inert atmosphere at 50 ℃. And then crushing and sieving to obtain the uniform porous composite silicon-based anode material.
Example 7
Metal lithium sheet, simple substance silicon and epoxy resin are mixed according to the mass ratio of 15:40:55, melting at 800 ℃ in an inert atmosphere, and preserving heat for 15 hours to obtain the composite material. The composite material is crushed and sieved to obtain uniform powder particles with the particle size smaller than 10 mu m. The powder particles were put into hydrofluoric acid (4 wt%) for hydrofluoric acid etching for 2 hours, and then washed. Drying is carried out under vacuum inert atmosphere at 50 ℃. And then crushing and sieving to obtain the uniform porous composite silicon-based anode material.
Example 8
Metal lithium sheet, simple substance silicon and epoxy resin are mixed according to the mass ratio of 15:40:55, melting at 1200 ℃ in an inert atmosphere, and preserving heat for 5 hours to obtain the composite material. The composite material is crushed and sieved to obtain uniform powder particles with the particle size smaller than 10 mu m. The powder particles were put into hydrofluoric acid (4 wt%) for hydrofluoric acid etching for 2 hours, and then washed. Drying is carried out under vacuum inert atmosphere at 50 ℃. And then crushing and sieving to obtain the uniform porous composite silicon-based anode material.
Example 9
The method comprises the steps of (1) mixing a metal lithium sheet, elemental silicon and epoxy resin according to a mass ratio of 20:30:50, melting at 950 ℃ in an inert atmosphere, and preserving heat for 20 hours to obtain the composite material. The composite material is crushed and sieved to obtain uniform powder particles with the particle size smaller than 10 mu m. The powder particles were put into hydrofluoric acid (4 wt%) for hydrofluoric acid etching for 2 hours, and then washed. Drying is carried out under vacuum inert atmosphere at 50 ℃. And then crushing and sieving to obtain the uniform porous composite silicon-based anode material.
Example 10
Metal lithium sheet, simple substance silicon and epoxy resin are mixed according to the mass ratio of 18:38:44, and melting at 950 ℃ in an inert atmosphere, and preserving heat for 20 hours to obtain the composite material. The composite material is crushed and sieved to obtain uniform powder particles with the particle size smaller than 10 mu m. The powder particles were put into hydrofluoric acid (4 wt%) for hydrofluoric acid etching for 2 hours, and then washed. Drying is carried out under vacuum inert atmosphere at 50 ℃. And then crushing and sieving to obtain the uniform porous composite silicon-based anode material.
Comparative example 1
The comparative example provides an all-solid-state composite silicon anode material, which specifically comprises the following steps:
Mixing metal lithium sheets and simple substance silicon according to a mass ratio of 40:60, melting at 500 ℃ in an inert atmosphere, and preserving heat for 15 hours to obtain the composite material. The composite material is crushed and sieved to obtain uniform powder particles with the particle size smaller than 10 mu m. The powder particles were put into hydrofluoric acid (4 wt%) for hydrofluoric acid etching for 2 hours, and then washed. Drying is carried out under vacuum inert atmosphere at 80 ℃. And then crushing and sieving to obtain the uniform porous composite silicon-based anode material.
Comparative example 2
The comparative example provides an all-solid-state composite silicon anode material, which specifically comprises the following steps:
mixing the metal lithium sheet and PVC according to the mass ratio of 45:55, melting at 900 ℃ in an inert atmosphere, and preserving heat for 12 hours to obtain the composite material. The composite material is crushed and sieved to obtain uniform powder particles with the particle size smaller than 10 mu m. The powder particles were put into hydrofluoric acid (4 wt%) for hydrofluoric acid etching for 2 hours, and then washed. Drying is carried out at 100 ℃ under vacuum inert atmosphere. And then crushing and sieving to obtain the uniform porous composite silicon-based anode material.
Comparative example 3
The comparative example provides an all-solid-state composite silicon anode material, which specifically comprises the following steps:
Mixing silicon dioxide and phenolic resin according to the mass ratio of 42:58, melting at 1000 ℃ in an inert atmosphere, and preserving heat for 15 hours to obtain the composite material. The composite material is crushed and sieved to obtain uniform powder particles with the particle size smaller than 10 mu m. The powder particles were put into hydrofluoric acid (4 wt%) for hydrofluoric acid etching for 2 hours, and then washed. Drying is carried out at 170 ℃ under vacuum inert atmosphere. And then crushing and sieving to obtain the uniform porous composite silicon-based anode material.
The result of scanning electron microscope observation of the all-solid-state composite silicon anode material prepared in example 1 is shown in fig. 1.
The electrochemical performance test was performed on all solid-state composite silicon anode materials obtained in examples 1 to 10 and comparative examples 1 to 3. The test method specifically comprises the following steps:
The method comprises the steps of selecting a high-pressure die to assemble a battery, firstly carrying out homogenate coating on materials prepared in the examples and the comparative examples to prepare a negative plate, secondly carrying out compression on sulfide electrolyte for 3min under 300Mpa, secondly carrying out compression on the negative plate for 3min under 800Mpa, then sequentially putting a10 mm steel sheet and a 6-8mm lithium sheet into the negative plate, and carrying out compression molding under 300Mpa for 3min again to assemble the solid-state die battery. And finally, carrying out charge and discharge test of 0.05C-2C on the assembled battery at 45 ℃ under the LAND battery test system with the model of CT-2001A, wherein the test voltage of the negative electrode is-0.6V-0.9V. The results are shown in Table 1, which are comparative data of the initial charge and 200-week capacity retention of the examples and comparative examples.
The in-situ pressure die is adopted, so that the in-situ testing device for testing the internal pressure change of the lithium ion battery on line can be used. The device adopts a high-precision pressure sensor and a controller, and can realize the internal pressure change detection precision of 1mbar at most. The die solid state battery cycle time pressure change can be tested, with a maximum pressure of up to 500mpa, and the results are shown in table 1.
The thickness change of the pole piece before and after charging and discharging was observed by using a Hitachi Regulus8100 scanning electron microscope, and the results are shown in Table 1.
TABLE 1
As can be seen from the results of table 1, the composite silicon anode material obtained in the examples has small volume expansion and excellent electrochemical properties, while the anode material obtained in the comparative examples has large volume expansion and poor electrochemical properties.
In summary, the silicon-based composite anode material with a uniform and porous structure is obtained, the deintercalation of lithium is facilitated, the structure is not obviously expanded, the charge-discharge cycle performance is good, and the carbon simple substance is dispersed on the surface and the inside of the anode material, so that the effect of relieving the volume expansion of the material and enhancing the conductivity of the material is achieved.
The above description is only of the preferred embodiments of the present invention and is not intended to limit the present invention, but various modifications and variations can be made to the present invention by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (10)

1. The all-solid-state composite silicon anode material is characterized by comprising a framework material formed by lithium and silicon, wherein carbon and organic matters are coated on the framework material to form an alloy compound of the lithium, the silicon-based material, the organic matters and a carbon simple substance, the all-solid-state composite silicon anode material has a porous structure, and the organic matters are at least one selected from acrylonitrile copolymer, phenolic resin, epoxy resin, polyfurfuryl alcohol, polyvinyl alcohol and polyvinyl chloride.
2. A method for preparing the all-solid-state composite silicon anode material according to claim 1, comprising: and (3) melting the mixture of the lithium source, the silicon-based material and the organic matters at a high temperature.
3. The method according to claim 2, wherein the melting temperature is 500 ℃ to 1200 ℃.
4. The method according to claim 3, wherein the temperature is maintained at the melting temperature for 1 to 20 hours.
5. The preparation method according to claim 2, wherein the mass ratio of the lithium source, the silicon-based material and the organic matter is (15-45): (10-40): (30-60).
6. The method according to claim 2, wherein the high-temperature melting is performed in an inert environment, and the reaction vessel is made of an inert material.
7. The method according to claim 2, wherein the lithium source is metallic lithium, and the metallic lithium is in the form of a sheet or powder;
and/or the silicon-based material is selected from at least one of elemental silicon, silicon oxide and silicon dioxide;
And/or the organic matter is selected from at least one of acrylonitrile copolymer, phenolic resin, epoxy resin, polyfurfuryl alcohol, polyvinyl alcohol and polyvinyl chloride.
8. The production method according to any one of claims 2 to 7, further comprising pulverizing the alloy compound obtained by high-temperature melting, and then acid etching; and washing and drying after acid etching, wherein the drying mode is vacuum drying, and the drying temperature is 50-200 ℃.
9. The method according to claim 8, wherein the acid etching is performed with at least one acid selected from hydrofluoric acid, hydrochloric acid and nitric acid.
10. The application of the all-solid-state composite silicon anode material as claimed in claim 1 or the all-solid-state composite silicon anode material prepared by the preparation method as claimed in any one of claims 2 to 9 in solid batteries.
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Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003263986A (en) * 2002-03-11 2003-09-19 Yuasa Corp Electrode material and lithium battery using the same
CN107017384A (en) * 2016-01-27 2017-08-04 陕西煤业化工技术研究院有限责任公司 A kind of preparation method of silicon-carbon composite cathode material

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2003263986A (en) * 2002-03-11 2003-09-19 Yuasa Corp Electrode material and lithium battery using the same
CN107017384A (en) * 2016-01-27 2017-08-04 陕西煤业化工技术研究院有限责任公司 A kind of preparation method of silicon-carbon composite cathode material

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