New Solid-State Battery Uses A Pure-Silicon Anode

Engineers have created a new type of solid-state battery that leverages an anode made with pure silicon. The team says their new battery design combines two subfields of battery research to create a single battery. The battery features a solid-state electrolyte and an all-silicon anode. The result is a silicon all-solid-state battery.

Initial testing found that the battery is safe, long-lasting, and has a high energy density. The battery design makes it appropriate for applications in a wide range of fields, including storing electricity on large grids and electric vehicles. The battery was designed by researchers from the University of California San Diego in collaboration with researchers from LG Energy Solutions.

One significant design characteristic for the new battery is a silicon anode known for energy density. The energy density of a silicon anode is ten times higher than the energy density of commonly used graphite anodes used in lithium-ion batteries built commercially today. However, silicon anodes aren't without their drawbacks, particularly for their expansion and contraction as the battery charges and discharges.

Silicon anodes also degrade when exposed to liquid electrolytes. Both of those downsides have prevented silicon anodes from being used in modern commercial lithium-ion batteries. However, research conducted by scientists has discovered a new path forward for all-silicon-anodes thanks to the discovery of new electrolytes.

The new battery configuration the team is investigating replaces the metallic lithium anode typically used in solid-state batteries. One challenge with metallic lithium anodes is elevated temperatures for charging, usually around 60 degrees Celsius or higher. In their research, the team demonstrated a fuel-cell at laboratory scale able to survive 500 charge and discharge cycles with 80 percent capacity at room temperature, which is progress for better using a silicon anode and solid-state batteries in general. In the battery, the team used a sulfide-based solid electrolyte which was found to be stable when used in batteries with all-silicon anodes. Research is currently ongoing.