Method for manufacturing silicon-based anode active material and lithium secondary battery using the same

Silicon nanowire anode material with uniform metal coating via electrodeposition removal and re-precipitation in strong acid

This technology involves removing randomly attached metal deposits from the surface of silicon nanowires created via Metal-Assisted Chemical Etching (MACE), followed by re-immersion in a diluted strong acid solution to uniformly precipitate metal particles onto the surface.

When silicon nanowires are used as an anode active material, an unstable Solid Electrolyte Interphase (SEI) layer forms on the surface during high-speed charge and discharge cycles. This leads to a simultaneous decline in specific capacity and cycle life.

This technology removes electrodeposited metals after MACE using nitric acid or similar agents, then uses a diluted strong acid solution to uniformly re-precipitate metal particles, such as silver (Ag), onto the nanowire surface. This enhances electrical conductivity and controls the formation of the SEI layer. It can be applied to silicon anodes in electric vehicle batteries requiring fast charging and high-power power tool cells, effectively slowing the reduction of specific capacity even under high-current conditions.

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Key Features:

• Forming silicon nanowires by immersing a silicon substrate in an etchant containing an aqueous hydrofluoric acid solution and dissolved metal.
• Removing randomly electrodeposited metal from the surface by immersing the etched silicon nanowires in a nitric acid etchant.
• Precipitating metal particles by immersing the silicon nanowires in a 0.01M to 1M diluted strong acid solution.
• Silicon nanowires for lithium secondary batteries used as an anode active material with metal particles, such as silver, uniformly distributed on the surface.

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