Manufacturing method for silicon-based anodes, silicon-based anodes using the same, and lithium secondary batteries containing them

Binder-free nanowire anode combining heat-treated exfoliated silicon thin films with displacement plating and etching

This technology is an anode manufacturing process that involves depositing a metal film on a silicon substrate, exfoliating the silicon thin film through heat treatment, and then applying a Metal-Assisted Chemical Etching (MACE) process to grow silicon nanowires.

Conventional slurry-type silicon anodes suffer from low electrical conductivity and shortened lifespans due to cumulative mechanical damage caused by silicon volume expansion during charging and discharging. Furthermore, existing nanowire growth processes are complex, which limits their mass production potential.

This technology utilizes a direct process that eliminates the need for conductive additives and binders. By exfoliating a metal film-silicon thin film stacked structure and performing chemical etching with an HF/H2O2 mixed etchant to form nanowires, it simultaneously improves electrical conductivity and cycle life. Because the nanowires are directly attached to the metal film, this structure can be applied to the development of high-energy-density cells for thin mobile batteries and wearables, enabling the realization of anodes with reduced electrode assembly steps and a higher ratio of active materials.

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Key Features:

• Forming a metal film with a thickness of 1 to 10㎛ on a silicon substrate using electroplating, sputtering, or chemical vapor deposition.
• Exfoliating the silicon thin film by heat-treating the metal-coated silicon substrate in a vacuum atmosphere at 300 to 800℃.
• Plating the silicon thin film by immersing it in a displacement plating bath containing silver nitrate dissolved in an aqueous hydrofluoric acid solution.
• Forming silicon nanowires by immersing the plated silicon thin film in a mixed etchant of hydrofluoric acid and hydrogen peroxide.

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