Engineers create a high performance all-solid-state battery with a pure-silicon anode.
Engineers created a new type of battery that weaves two promising battery sub-fields into a single battery. The battery uses both a solid state electrolyte and an all-silicon anode, making it a silicon all-solid-state battery. The initial rounds of tests show that the new battery is safe, long lasting, and energy dense. It holds promise for a wide range of applications from grid storage to electric vehicles.
The battery technology is described in the September 24, 2021 issue of the journal Science. University of California San Diego nanoengineers led the research, in collaboration with researchers at LG Energy Solution.
Silicon anodes are famous for their energy density, which is 10 times greater than the graphite anodes most often used in today’s commercial lithium ion batteries. On the other hand, silicon anodes are infamous for how they expand and contract as the battery charges and discharges, and for how they degrade with liquid electrolytes. These challenges have kept all-silicon anodes out of commercial lithium ion batteries despite the tantalizing energy density. The new work published in Science provides a promising path forward for all-silicon-anodes, thanks to the right electrolyte.
1) The all solid-state battery consists of a cathode composite layer, a sulfide solid electrolyte layer, and a carbon free micro-silicon anode. 2) Before charging, discrete micro-scale Silicon particles make up the energy dense anode. During battery charging, positive Lithium ions move from the cathode to the anode, and a stable 2D interface is formed. 3) As more Lithium ions move into the anode, it reacts with micro-Silicon to form interconnected Lithium-Silicon alloy (Li-Si) particles. The reaction continues to propagate throughout the electrode. 4) The reaction causes expansion and densification of the micro-Silicon particles, forming a dense Li-Si alloy electrode. The mechanical properties of the Li-Si alloy and the solid electrolyte have a crucial role in maintaining the integrity and contact along the 2D interfacial plane. Credit: University of California San Diego
“With this battery configuration, we are opening a new territory for solid-state batteries using