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Porous silicon copper coated electrode for lithium ion battery and preparation method thereof

A lithium-ion battery, porous silicon technology, applied in battery electrodes, non-aqueous electrolyte battery electrodes, nanotechnology for materials and surface science, etc., can solve problems such as inability to produce firmness, accelerated capacity decay, and electrode structure damage. To achieve the effect of ensuring normal charging and discharging, reducing contact resistance and increasing contact area

Pending Publication Date: 2017-05-31
SOUTH CHINA UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, during the alloying reaction process of silicon and lithium, the silicon material will undergo severe volume expansion (>400%), which will easily lead to the rapid pulverization of the active material during the cycle, so that it will fall off from the copper current collector, and the silicon and copper will be in electrical contact. Weakened, making the battery cycle life rapidly decay
At the same time, due to the volume expansion effect of the silicon material, the silicon material cannot produce a solid surface solid electrolyte film in the electrolyte, the electrode structure is destroyed, and a new electronic insulation (SEI) film will continue to be formed on the newly exposed silicon surface, resulting in The charge and discharge efficiency is reduced and the capacity decay is accelerated

Method used

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  • Porous silicon copper coated electrode for lithium ion battery and preparation method thereof
  • Porous silicon copper coated electrode for lithium ion battery and preparation method thereof
  • Porous silicon copper coated electrode for lithium ion battery and preparation method thereof

Examples

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Effect test

Embodiment 1

[0036] A preparation of a porous silicon copper-plated electrode for lithium-ion batteries, comprising the steps of:

[0037] Core preparation

[0038] (1) Cleaning of polysilicon powder: Soak 10g polysilicon powder of 400 mesh with 10wt% HCl solution for 30min to remove impurities; filter with 1000 mesh standard sieve and clean with deionized water;

[0039] (2) Deposit nano-Ag particles: put the cleaned polysilicon powder into AgNO 3 and HF mixed solution (mixed solution, AgNO 3 The concentration of HF is 0.02mol / L, the concentration of HF is 2wt%), deposit Ag for 2min, and form nano-particle Ag on the surface of polysilicon; filter with 1000 mesh standard sieve, and clean with deionized water;

[0040] (3) Presentation of porous silicon: the polysilicon powder deposited with Ag particles was placed in HF and H 2 o 2 mixed corrosion solution (in the mixed corrosion solution, the concentration of HF is 2.5mol / L, H 2 o 2 The concentration is 1 wt%), at 25°C, the reaction...

Embodiment 2

[0047] The porous silicon copper-plated electrode prepared in Example 1 is used in a lithium-ion half-cell, and the schematic diagram of the assembly is as follows figure 2 As shown, from top to bottom, it includes an upper battery case 1, a shrapnel 2, a gasket 3, a lithium sheet 4, a diaphragm 5, an electrolyte 6, a lower battery case 7 and a porous silicon copper-plated electrode 8;

[0048] The porous silicon copper-plated electrode 8 is placed on the lower battery shell 7, the electrolyte 6 directly infiltrates the porous silicon copper-plated electrode 8, and the electrolyte 6 fills the entire cavity composed of the porous silicon copper-plated electrode 8, the lower battery shell 7 and the diaphragm 5 ;

[0049] The lithium sheet 4 is closely attached to the diaphragm 5, and the upper surface of the lithium sheet 4 is sequentially placed with a gasket 3 and a shrapnel 2 from bottom to top. The gasket 3 and the shrapnel 2 play a role in adjusting the pressure; the shrap...

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Abstract

The invention discloses a porous silicon copper coated electrode for a lithium ion battery and a preparation method thereof. The porous silicon copper coated electrode is in a cylindrical shape and consists of copper coated porous silicon particles; each copper coated porous silicon particle consists of an outer case and an inner core; the outer case is a copper particle and is of a porous nanostructure; the inner core is porous silicon. The preparation method comprises the following steps of (1) polycrystalline silicon powder pretreatment; (2) nanometer Ag particle deposition; (3) porous silicon preparation; (4) outer case preparation; (5) electrode formation. The porous silicon copper coated electrode has the advantages that the copper particles and silicon are organically and tightly combined; the contact area is increased; the contact resistance is effectively reduced; the electrode electroconductibility is greatly improved; the volume expansion of the silicon in a lithiation process is limited to the greatest degree by the copper particles; the lithium ion battery failure due to falling and separation of the silicon from the surface of a current collector in the battery cyclic charging and discharging processes can be effectively prevented, so that the service life of the lithium ion battery is prolonged; the cyclic stability of the lithium ion battery is improved.

Description

technical field [0001] The invention relates to the technical field of lithium ion batteries, in particular to a porous silicon copper-plated electrode for lithium ion batteries and a preparation method thereof. Background technique [0002] Lithium-ion battery is a green high-energy rechargeable chemical power source, which has outstanding advantages such as high voltage, high energy density, good cycle performance, small self-discharge, and no memory effect. It has been widely used in defense industry and other fields. At present, in the commercial lithium-ion battery system, graphite-like carbon is generally used as the negative electrode material, but the theoretical capacity of graphite is only 372mAh / g, and the rate performance is not good. The development of new high-capacity negative electrode materials has become a research hotspot. The theoretical specific capacity of silicon is as high as 4200 mAh / g, which is an order of magnitude higher than that of graphite-bas...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/13H01M4/139H01M4/66H01M4/75H01M10/0525B82Y30/00
CPCH01M4/13H01M4/139H01M4/667H01M4/75H01M10/0525B82Y30/00Y02E60/10
Inventor 袁伟潘保有邱志强罗健黄诗敏闫志国谭振豪汤勇
Owner SOUTH CHINA UNIV OF TECH
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