Porous silicon negative electrode material for lithium ion battery and preparation method thereof

A technology for lithium-ion batteries and negative electrode materials, applied in battery electrodes, nanotechnology for materials and surface science, negative electrodes, etc., can solve the problems of cycle performance deterioration, active material loss, material structure collapse, etc., and achieve excellent cycle. performance, high first-time efficiency, and improved conductivity

Active Publication Date: 2020-09-04
MAANSHAN KEDA PURUI ENERGY TECH CO LTD +2
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, due to the poor conductivity of the silicon material itself, and the volume expansion of silicon during charging is as high as 300%, the volume expansion during charging and discharging can easily lead to the collapse of the material structure and the peeling and pulverization of the electrodes, resulting in the loss of active materials, which in turn leads to a sharp drop in battery capacity. decrease, the cycle performance is seriously deteriorated

Method used

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  • Porous silicon negative electrode material for lithium ion battery and preparation method thereof
  • Porous silicon negative electrode material for lithium ion battery and preparation method thereof
  • Porous silicon negative electrode material for lithium ion battery and preparation method thereof

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Embodiment 1

[0035] A method for preparing a porous silicon negative electrode material for a lithium ion battery, comprising the steps of:

[0036] (1) Preparation of nanoporous silicon: Add 1000 g of porous silicon powder with a median particle size of 1 μm and a purity of 99.99% and methanol into the dispersion tank of the sand mill, control the solid content of the mixed solution to be 10%, and then add grinding aid Aluminum chloride, the mass ratio of aluminum chloride and porous silicon powder is 1:100, and the stirring is started for 30 minutes; the material of the grinding beads is hard alloy, and the mass ratio of grinding beads and silicon powder is 30:1; The mixed solution of the mixed solution is introduced into the sand mill, the linear speed of the sand mill is 16m / s, and the grinding time is 50h to obtain a porous silicon slurry; the mass content of oxygen in the nanoporous silicon is obtained by testing. The mass content of the nanoporous silicon is 26%. The median particle...

Embodiment 2

[0040](2) Preparation of nanoporous silicon: 1000 g of porous silicon powder with a median particle size of 30 μm and a purity of 99.95% and ethanol are added to the dispersion tank of the sand mill, and the solid content of the mixed solution is controlled to be 20%, and then a grinding aid is added Sodium pyrophosphate, the mass ratio of sodium pyrophosphate and porous silicon powder is 3:100, start stirring for 30 minutes; the material of the grinding beads is zirconium silicate, and the mass ratio of grinding beads and silicon powder is 20:1; The mixed solution is introduced into the sand mill, the linear speed of the sand mill is 15m / s, and the grinding time is 70h to obtain the porous silicon slurry; the mass content of the oxygen element in the nanoporous silicon is 38% through detection, and the nanoporous silicon The median particle size is 63nm, and the silicon grain size is 8.9nm;

[0041] (2) Preparation of porous silicon negative electrode material precursor: addi...

Embodiment 3

[0044] (1) Preparation of nanoporous silicon: 1000 g of porous silicon powder with a median particle size of 60 μm and a purity of 99.91% and isopropanol are added to the dispersion tank of the sand mill to control the solid content of the mixed solution to be 30%, and then add auxiliary Abrasive sodium polyacrylate, the mass ratio of sodium polyacrylate to porous silicon powder is 6:100, start stirring for 30 minutes; the material of the grinding beads is zirconium silicate, and the mass ratio of grinding beads to silicon powder is 15:1; The mixed solution in the tank is introduced into a sand mill, the linear speed of the sand mill is 15m / s, and the grinding time is 40h to obtain a porous silicon slurry; the mass content of oxygen in the nanoporous silicon is 20% through detection, and the nanoporous The median particle size of silicon is 92nm, and the size of silicon grains is 12.9nm;

[0045] (2) Preparation of the porous silicon negative electrode material precursor: addi...

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Abstract

The invention belongs to the technical field of lithium ion batteries, and specifically relates to a porous silicon negative electrode material for a lithium ion battery and a preparation method thereof. The porous silicon negative electrode material comprises nano-porous silicon, conductive carbon and amorphous carbon. The nano-porous silicon contains oxygen, the oxygen content is 10-40wt%, and the nano-porous silicon in the negative electrode material accounts for 30-80wt%. The conductive carbon accounts for 5 to 30 weight percent. The ratio of the amorphous carbon is 10 to 40 weight percent. The median particle size D50 of the nano-porous silicon is 110 nm or below, the maximum particle size D100 of the nano-porous silicon is 260 nm or below, the nano-porous silicon is prepared througha wet grinding process, the raw material is porous silicon powder, and the porous silicon negative electrode material disclosed by the invention has excellent electrochemical performance, high specific capacity, excellent cycle performance and high initial efficiency.

Description

technical field [0001] The invention belongs to the technical field of lithium ion batteries, and in particular relates to a porous silicon negative electrode material for lithium ion batteries and a preparation method thereof. Background technique [0002] At present, the conventional lithium ion negative electrode material is mainly graphite negative electrode, but the theoretical specific capacity of graphite negative electrode is only 372mAh / g, which cannot meet the urgent needs of users. The theoretical capacity of silicon is as high as 4200mAh / g, which is more than 10 times the capacity of graphite anode materials. At the same time, the coulombic efficiency of silicon-carbon composites is also close to that of graphite anodes. It is cheap, environmentally friendly, and has abundant earth reserves. It is a new generation of high-capacity The best choice for negative electrode materials. However, due to the poor conductivity of the silicon material itself, and the volum...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/38H01M4/36H01M4/62H01M10/0525B82Y30/00B82Y40/00C09C1/56C01B33/02C01B32/05
CPCB82Y30/00B82Y40/00C01B33/02C09C1/56C01B32/05H01M4/364H01M4/366H01M4/386H01M4/625H01M4/628H01M10/0525H01M2004/027Y02E60/10
Inventor 胡亮张少波王浩张小龙俞有康
Owner MAANSHAN KEDA PURUI ENERGY TECH CO LTD
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