Solid-State All-Silicon Anode Batteries Offer Boosted Capacities, Charging Rates

Engineers at the University of California at San Diego (UCSD) have created a solid-state battery with a pure silicon anode — the first step towards batteries with an energy density some 10 times greater than today's lithium-ion batteries.

"The solid-state silicon approach overcomes many limitations in conventional batteries," claims Darren H. S. Tan, first author of the paper describing the team's work. "It presents exciting opportunities for us to meet market demands for higher volumetric energy, lowered costs, and safer batteries especially for grid energy storage."

Silicon anodes are being investigated to replace graphite anodes in future batteries, offering a dramatic improvement in both energy density and recharge rate. The only trouble: The silicon anodes have a tendency to expand and contract during charging and discharging, and to degrade when in contact with liquid electrolytes.

The new battery appears to solve both problems, primarily through the replacement of liquid electrolytes with solid-state equivalents. In testing, a solid-state silicon-anode fuel cell was shown to deliver 500 charge-discharge cycles and yet retain 80 per cent of its original energy storage capacity — a major boost over existing design.

First author Tan is already looking towards commercialization of the battery, setting up the startup UNIGRID Battery to bring the design to market. Additional research on "related fundamental work" is also underway with LG Energy Solution (LGES), with president Myung-hwan Kim saying the company is "delighted" with the research and will "continue its effort to foster state-of-the-art techniques in leading research of next-generation battery cells" including further partnerships with UCSD.

The team's paper has been published in the journal Science under closed-access terms.