Fast Lithium-Ion Conducting Thin-Film Electrolytes Integrated Directly on Flexible Substrates for High-Power Solid-State Batteries

By utilizing an equilibrium processing strategy that enables co‐firing of oxides and base metals, a means to integrate the lithium‐stable fast lithium‐ion conductor lanthanum lithium tantalate directly with a thin copper foil current collector appropriate for a solid‐state battery is presented. This resulting thin‐film electrolyte possesses a room temperature lithium‐ion conductivity of 1.5 × 10−5 S cm−1, which has the potential to increase the power of a solid‐state battery over current state of the art.