Elastic and Li-ion-percolating hybrid membrane stabilizes Li metal plating.

Abstract

Lithium metal batteries are capable of revolutionizing the battery marketplace for electrical vehicles, owing to the high capacity and low voltage offered by Li metal. Current exploitation of Li metal electrodes, however, is plagued by their exhaustive parasitic reactions with liquid electrolytes and dendritic growth, which pose concerns to both cell performance and safety. We demonstrate that a hybrid membrane, both elastic and Li⁺-ion percolating, can stabilize Li plating/stripping with high Coulombic efficiency. The compact packing of a Li⁺ solid electrolyte phase offers percolated Li⁺-conducting channels and the consequent infiltration of an elastic polymer endows membrane flexibility to accommodate volume changes. The protected electrode allows Li plating with 95.8% efficiency for 200 cycles and stable operation of an LTO|Li cell for 2,000 cycles. This rationally structured membrane represents an interface engineering approach toward stabilized Li metal electrodes.