Mechanically Robust Ultrathin Solid Electrolyte Membranes Using a Porous Net Template for All-Solid-State Batteries

All-solid-state batteries (ASBs) have been identified as a potential next-generation technology for safe energy storage. However, the current pellet form of solid electrolytes (SEs) exhibits low cell-level energy densities and mechanical brittleness, and this has hampered the commercialization of ASBs. In this work, we report on the development of an ultrathin SE membrane that can be reduced to a thickness of 31 μm with minimal thermal shrinkage at 140 °C, while exhibiting robust mechanical properties (tensile strength of 19.6 MPa). Due to its exceptional ionic conductivity of 0.55 mS/cm and the corresponding areal conductance of 84 mS/cm², the SE membrane-incorporated ASB displays cell-level gravimetric and volumetric energy densities of 127.9 Wh/kg_cell and 140.7 Wh/L_cell, respectively. These values represent a 7.6- and 5.7-fold increase over those achieved with conventional SE pellet cells. Our results demonstrate the potential of the developed SE membrane to overcome the critical challenges in the commercialization of ASBs.