SOLID ELECTROLYTE, POSITIVE ELECTRODE, AND SOLID-STATE BATTERY

A solid electrolyte that includes: a first crystallite in a primary particle and having a first crystal structure; a second crystallite in the primary particle and having a second crystal structure that is different from the first crystal structure; and an amorphous phase, the first crystallite and the second crystallite each contain lithium, the first crystal structure is a hexagonal crystal, the second crystal structure is an orthorhombic crystal, and the crystallite size of the first crystallite and the crystallite size of the second crystallite are each 50 nm or less.