Engineers from LG Energy Solutions have created a new battery that combines two sub-field technologies into a new solid-state battery.
LG worked with the University of California San Diego and the battery could be used in a wide range of applications from grid storage to electric vehicles.
The battery uses both a solid-state electrolyte and an all-silicon anode to make it a silicon solid-state battery with initial testing indicating the battery is safe, long lasting and energy dense.
Silicon anodes are typically good for energy density, about 10 times greater than graphite anodes, and expand and contract as the battery charges and discharges. However, they can quickly degrade with liquid electrolytes. Theses challenges have kept all-silicon anodes out of commercial lithium-ion batteries.
"With this battery configuration, we are opening a new territory for solid-state batteries using alloy anodes such as silicon," said Darren H. S. Tan, a graduate from U.C. San Diego Jacobs School of Engineering.
Silicon anode allows for much faster charging rates at room to low temperatures, while maintaining high energy densities.
The team demonstrated a laboratory scale fuel cell that delivers 500 charge and discharge cycles with 80% capacity retention at room temperature, which represents exciting progress for both the silicon anode and solid-state battery communities.
The team was able to remove the liquid electrolyte and instead used a sulfide-based solid electrolyte with experiments showing the solid electrolyte is stable in batteries with all-silicon anodes.
"This new work offers a promising solution to the silicon anode problem, though there is more work to do," said Shirley Meng, professor at U.C. San Diego who helped with the development of the battery. "I see this project as a validation of our approach to battery research here at U.C. San Diego. We pair the most rigorous theoretical and experimental work with creativity and outside-the-box thinking. We also know how to interact with industry partners while pursuing tough fundamental challenges."
Previous efforts to commercialize silicon alloy anodes focused on silicon-graphite composites, or by combining nano-structured particles with polymeric binders. However, these struggled with poor stability.
Swapping out the liquid electrolyte for a solid electrolyte and removing the carbon and binders from the silicon anode, researchers were able to avoid the challenges that happen when the anode become soaked in the organic liquid electrolyte as the battery functions.
The two part move allowed researchers to reap the benefits of low-cost, high energy and environmentally benign properties of silicon.