Gallium-substituted solid electrolyte material, and all-solid-state lithium ion secondary battery

Abstract

Provided is a novel solid electrolyte material of high density and high ionic conductivity, and an all-solid-state lithium ion secondary battery that utilizes the solid electrolyte material. The solid electrolyte material has a chemical composition represented by Li7-3xGaxLa3Zr2O12 (0.08≤x<0.5), has a relative density of 99% or higher, belongs to space group I-43d, in the cubic system, and has a garnet-type structure. The lithium ion conductivity of the solid electrolyte material is 2.0×10−3 S/cm or higher. The solid electrolyte material has a lattice constant a such that 1.29 nm≤a≤1.30 nm, and lithium ions occupy the 12a site, the 12b site and two types of 48e site, and gallium occupies the 12a site and the 12b site, in the crystal structure. The all-solid-state lithium ion secondary battery has a positive electrode, a negative electrode, and a solid electrolyte. The solid electrolyte is made up of the solid electrolyte material of the present invention.

Dependencies are inferred from the claim text.