Enhanced Li‐ion conductivity of strontium doped Li‐excess garnet‐type Li 7+x La 3‐x Sr x Zr 2 O 12

The mechanism underlying the enhancement of the conductivity of Li 7 La 3 Zr 2 O 12 (LLZO), an oxide‐based solid electrolyte that contains excess Li, was experimentally investigated through subvalent cation substitution. We prepared Sr‐substituted Li‐rich LLZO with high conductivity of the order of 10 −4 S/cm by using a solid‐state method. We investigated the mechanism underlying the conductivity enhancement via detailed structural analysis through Sr K ‐edge X‐ray absorption near edge spectroscopy and X‐ray diffraction and neutron powder diffraction analyses. The results suggested that the conductivity enhancement is due to the change in Li + arrangement caused by the incorporation of excess Li into the LLZO lattice.