Silicon-based composite material containing lithium phosphate coating layer constructed by in-situ conversion and preparation method of silicon-based composite material

A silicon-based composite material, silicon-based material technology, applied in chemical instruments and methods, silicon oxide, phosphorus compounds, etc., can solve the problems of affecting the capacity of active substances, reducing the activity of newly exposed interfaces, and not significantly improving water resistance, etc. Achieve the effect of inhibiting gas production, improving dual stability and improving cycle stability

Active Publication Date: 2021-09-21
BEIJING IAMETAL NEW ENERGY TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This method can solve the problem of poor water resistance of the material to a certain extent, but because the pre-lithiated silicon oxide material coating aluminum phosphate polymer in this method is mainly to directly mix the pre-lithiated silicon oxide material aqueous solution and the aluminum salt aqueous solution and then filter Dry coating can not accurately find the position where the residual alkali exists, so if the coating is not dense, some residual alkali will still be exposed, so that the improvement of water resistance will not be obvious, and unnecessary aluminum salt will be introduced, which will affect the activity to a certain extent capacity of matter
[0007] It can be seen that the current residual alkali treatment technology for lithiated silicon-based anode materials still has certain defects, and it has not considered the interface protection that can be precisely positioned to reduce the activity of the newly exposed interface. It is urgent to develop new strategies to reduce the residual alkali on the surface. Improve the interface stability of the material, and further improve the processability and practical performance of lithiated silicon-based negative electrode materials

Method used

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  • Silicon-based composite material containing lithium phosphate coating layer constructed by in-situ conversion and preparation method of silicon-based composite material
  • Silicon-based composite material containing lithium phosphate coating layer constructed by in-situ conversion and preparation method of silicon-based composite material
  • Silicon-based composite material containing lithium phosphate coating layer constructed by in-situ conversion and preparation method of silicon-based composite material

Examples

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Effect test

Embodiment 1

[0038] (1) Preparation of carbon-coated pre-lithiated silicon-based materials

[0039] Add 500 g of silicon oxide particles with a median particle size of about 6 μm into a CVD vapor deposition furnace for carbon coating treatment, pass acetylene gas at a flow rate of 600 sccm, deposit at 750 °C for 3 h, and wrap the The coated material was placed under the condition of nitrogen protection, and the temperature was raised to 900 °C at a heating rate of 5 °C / min for 1 h to obtain a carbon-coated silicon-based material. The carbon-coated silicon-based material obtained above and 49.8 g of lithium hydride powder were added to a high-speed mixer, and mixed for 30 min at a stirring rate of 1000 r / min under the protection of an inert atmosphere to obtain uniformly mixed raw materials, and the raw materials were placed in Under the protection of argon, the temperature was raised to 600 °C for 1 h at a heating rate of 5 °C / min, and a carbon-coated pre-lithiated silicon-based material w...

Embodiment 2

[0046] Other conditions are the same as in Example 1, except that 1 g of ammonium dihydrogen phosphate is used instead of phosphoric acid.

Embodiment 3

[0048] Other conditions are the same as in Example 1, except that phosphoric acid is replaced by a mixture of 1 g of ammonium dihydrogen phosphate and lithium dihydrogen phosphate, wherein the mass ratio of ammonium dihydrogen phosphate to lithium dihydrogen phosphate is 1:1.

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Abstract

The invention discloses a silicon-based composite material containing a lithium phosphate coating layer constructed by in-situ conversion and a preparation method of the silicon-based composite material. The silicon-based composite material is of a multi-layer core-shell structure and comprises an inner core formed by a lithiated silicon-based material composed of a silicon-based material and lithium silicate and an outer shell formed by a composite coating layer jointly formed by carbon and lithium phosphate. According to the method, the residual alkali on the surface of the lithiated silicon-based composite material is converted into the phosphate coating layer in situ through a simple solution method, so that bad residual alkali components on the surface can be removed in a precise positioning manner, and meanwhile, a stable interface protection layer is thus formed by conversion.

Description

technical field [0001] The invention belongs to the technical field of batteries, and specifically relates to an in-situ conversion strategy to construct a silicon-based composite material containing a lithium phosphate composite coating layer structure, a preparation method and an application thereof. Background technique [0002] Lithium-ion batteries have become the most widely used energy storage devices due to their high energy density and long cycle life. Favored in the field of large-scale energy storage. The rapid expansion of application fields has put forward increasing demands on the energy density of lithium-ion batteries. Graphite is still the main anode material for commercial lithium-ion batteries, and its specific capacity (372 mAh / g) can no longer meet the needs of high energy density. Therefore, finding high-capacity anode materials has always been a research hotspot in the field of lithium-ion batteries. [0003] Among many candidate anode materials, sil...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/36H01M4/48H01M4/62H01M10/0525C01B33/02C01B33/113C01B33/32C01B32/00C01B25/30
CPCH01M4/366H01M4/483H01M4/628H01M10/0525C01B33/02C01B33/113C01B33/32C01B32/00C01B25/301C01P2004/80C01P2004/03C01P2004/04C01P2006/40H01M2004/021H01M2004/027Y02E60/10
Inventor 李阁张旭东鲁卓雅程晓彦岳风树
Owner BEIJING IAMETAL NEW ENERGY TECH CO LTD
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