A medium-entropy garnet-type oxide as a solid electrolyte with enhanced air stability for Li-ion batteries

A novel medium-entropy garnet Li 6.5 La 3 Zr 0.5 Ta 0.5 Nb 0.5 Y 0.5 O 12 (LLZTNYO) was synthesized via a solid-phase method. LLZTNYO exhibited high Li-ion conductivity (1.87 × 10 −4 S cm −1 ) and maintained for 30 days in an air without decay.