Silicon anode, manufacturing method thereof, and battery comprising the same

Silicon anode with stabilized solid-electrolyte interface via lithium-alloying thin-film deposition

This technology involves depositing a 30–80 nm thick layer of a lithium-alloying metal, such as silver (Ag), onto the surface of a silicon anode active material layer to enhance interfacial contact with the solid electrolyte and ensure electrochemical stability during charge and discharge cycles.

Silicon anodes suffer from low ionic and electronic conductivity and significant volume expansion during charge and discharge, leading to side reactions or interfacial delamination when used with sulfide-based solid electrolytes. These issues have historically limited both cycle life and discharge capacity.

This technology forms a 30–80 nm thick silver (Ag) metal layer on an anode active material layer composed of silicon, CNTs, and PVDF using DC sputtering. During charging, this layer alloys with lithium, becoming soft and adhesive, which maintains uniform contact with the solid electrolyte and reduces interfacial resistance. Applicable to all-solid-state batteries for EVs and power sources for communication and transport devices, this technology leverages the high capacity of silicon anodes while preventing capacity loss caused by interfacial delamination.

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Key Features:

• Anode active material layer formed on a copper foil current collector, comprising silicon, carbon nanotube conductive agents, and polyvinylidene fluoride binder
• Silver (Ag) lithium-alloying metal layer formed to a thickness of 30 to 80 nm on the anode active material layer via DC sputtering
• Solid electrolyte layer interposed between the silicon anode and a cathode containing lithium metal to form a battery
• Lithium alloy layer formed at the interface between the silicon anode and the solid electrolyte layer after charge/discharge through the bonding of the lithium-alloying metal layer and lithium ions

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This invention was developed with support from the Ministry of Science and ICT under the project for developing bridge technologies for large-area, 600Wh/L-class all-solid-state EV batteries.

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