To prepare the Li-In alloy anode CR2016 coin cells were assembled with In as cathode, Li as anode, and liquid electrolyte (1 M LiTFSI in DOL and DME in 1:1 vol. ratio. After 40 h of Li plating at a current density of 0.25 mA/cm 2 (Fig. ), the Li-In disk was obtained after cell disassembling, washing with DME, and subsequent drying at 50 °C in an oven inside Ar-filled glovebox. Lastly, the Li-In disc (10 mm diameter) was attached to another side of the LPSCl pellet and pressed at 150 MPa. All the half-cell SSBs were assembled inside an Ar-filled glove box (H2O < 0.1 ppm, O2 < 0.1 ppm). The half cells were tested at room temperature (25 °C) and 120 MPa pressure for EIS and GCPL using VMP-300 potentiostat (BioLogic) and Neware battery cycler.