Lithium ion battery anode material and preparation method thereof

A lithium-ion battery and negative electrode material technology, which is applied in battery electrodes, non-aqueous electrolyte battery electrodes, circuits, etc., can solve the problems of battery cycle stability decline, electrode sheet loosening, volume change, etc., to improve the first charge and discharge efficiency and Cyclic stability, improved voltage hysteresis, and uniform particle size distribution

Inactive Publication Date: 2010-10-13
HUBEI SANJUN BATTERY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, during the process of lithium intercalation and deintercalation of silicon materials, there is a serious volume change, which easily causes the pulverization of silicon particles, loosens the electrode sheet, causes the active material to fall off from the current collector, and leads to a significant decrease in the cycle stability of the battery.
In order to overcome the volume effect of silicon, nanostructured silicon-based composite materials are generally used to improve the cycle performance of silicon anode materials, but the silicon in such composite materials will be exposed in the electrolyte, and an unstable SEI will be formed on the silicon surface. film, which reduces the cycle performance of the electrode material

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0018] Preparation of anode materials for lithium-ion batteries

[0019] Dissolve PVC (polyvinyl chloride) in an appropriate amount of tetrahydrofuran to obtain a solution with a certain viscosity, and then slowly add nano-silica powder and graphite into the solution under magnetic stirring. The weight ratio of nano-silica powder and graphite is 100: 120. At room temperature, after the solvent is completely volatilized, a bulk silicon / carbon composite material precursor is formed, and the silicon / carbon composite material precursor is roasted at 900°C for 2 hours under the protection of a mixed gas to obtain step (1) The silicon / carbon composite material is nano-silicon / cracked carbon / graphite, so that the weight ratio of nano-silicon: cracked carbon: graphite is 100:48:72.

[0020] The silicon / carbon composite material is ground into powder, and then the powder is evenly dispersed in the alcohol solution of phenolic resin to form a slurry with a certain viscosity, and the sl...

Embodiment 2

[0027] Preparation of anode materials for lithium-ion batteries

[0028] Dissolve PVC in an appropriate amount of tetrahydrofuran to obtain a solution with a certain viscosity, and then slowly add nano-silica powder and graphite into the solution under magnetic stirring. The weight ratio of nano-silica powder and graphite is 100:135. At room temperature, after the solvent is completely volatilized, a bulk silicon / carbon composite material precursor is formed, and the silicon / carbon composite material precursor is roasted at 850°C for 2.5 hours under the protection of a mixed gas to obtain step (1) The silicon / carbon composite material is nano-silicon / cracked carbon / graphite, so that the weight ratio of nano-silicon: cracked carbon: graphite is 100:55:80.

[0029] The silicon / carbon composite material is ground into powder, and then the powder is evenly dispersed in the alcohol solution of phenolic resin to form a slurry with a certain viscosity, and the slurry is atomized into...

Embodiment 3

[0036] Preparation of anode materials for lithium-ion batteries

[0037] Dissolve PVC in an appropriate amount of tetrahydrofuran to obtain a solution with a certain viscosity, and then slowly add nano-silica powder and graphite into the solution under magnetic stirring. The weight ratio of nano-silica powder and graphite is 100:148. At room temperature, after the solvent is completely volatilized, a bulk silicon / carbon composite material precursor is formed, and the silicon / carbon composite material precursor is roasted at 900°C for 2 hours under the protection of a mixed gas to obtain step (1) The silicon / carbon composite material is nano-silicon / cracked carbon / graphite, so that the weight ratio of nano-silicon: cracked carbon: graphite is 100:58:90.

[0038] The silicon / carbon composite material is ground into powder, and then the powder is evenly dispersed in the alcohol solution of phenolic resin to form a slurry with a certain viscosity, and the slurry is atomized into l...

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Abstract

The invention discloses a lithium ion battery anode material, which is characterized in that a carbon coating layer is coated on a silicon / carbon composite material. The invention also discloses a preparation method of the lithium ion battery anode material. The carbon shell layer of the carbon-coated silicon / carbon composite material prevents exposed silicon on the surface of the composite material from directly contacting with electrolyte, and a stable SEI film is formed on the surface of the carbon-coated silicon / carbon composite material, thereby improving the initial charge-discharge efficiency and the cycle stability.

Description

technical field [0001] The invention relates to the field of lithium ion batteries, in particular to a preparation method of negative electrode materials for lithium ion batteries. Background technique [0002] Due to the rapid development and wide application of portable electronic devices and electric vehicles, there is an urgent need for lithium-ion batteries with high specific energy and long cycle life. At present, commercially used lithium-ion batteries mainly use graphite as the negative electrode material. However, the theoretical specific capacity of graphite is only 372mAh / g, which limits the further improvement of the specific energy of lithium-ion batteries. Silicon has attracted great attention of researchers because of its extremely high theoretical lithium intercalation specific capacity (4200mAh / g) and low lithium storage potential. However, during the lithium-deintercalation process of silicon materials, there is a serious volume change, which easily causes...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M4/13H01M4/139
CPCY02E60/122Y02E60/10
Inventor 吴合年李炽强孙嘉遥
Owner HUBEI SANJUN BATTERY
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