Temperature Dependence of Lithium Anode Voiding in Argyrodite Solid-State Batteries

Void formation at the Li/ceramic electrolyte interface of an all-solid-state battery on discharge results in high local current densities, dendrites on charge, and cell failure. Here, we show that such voiding is reduced at the Li/Li6PS5Cl interface at elevated temperatures, sufficient to increase the critical current before voiding and cell failure from <0.25 mA cm(-2) at 25 degrees C to 0.25 mA cm(-2) at 60 degrees C and 0.5 mA cm(-2) at 80 degrees C under a relatively low stack-pressure of 1 MPa. Increasing the stack-pressure to 5 MPa and temperature to 80 degrees C permits stable cycling at 2.5 mA cm(-2). It is also shown that the charge-transfer resistance at the Li/Li6PS5Cl interface depends on pressure and temperature, with relatively high pressures required to maintain low charge-transfer resistance at -20 degrees C. These results are consistent with the plastic deformation of Li metal dominating the performance of the Li anode, posing challenges for the implementation of solid-state cells with Li anodes.