Solid electrolyte, method of producing solid electrolyte, and battery

A method of producing a solid electrolyte, comprising:

• a) preparing a compound expressed by a composition formula of LiaMbXc and a compound expressed by a composition formula of LidAeOf by using values a to f that are greater than 0, where M is an element serving as a trivalent cation, X is a halogen element, A is a sulfur element or a phosphorus element, the values a to f satisfy 0.8c≤(a+3b)≤1.2c and 1.6f≤(d+n×e)≤2.4f, and when A is a sulfur element, n is 4 or 6, and when A is a phosphorus element, n is 5;
• and
• b) subjecting LiaMbXc and LidAeOf to a mechanical milling process,
• wherein, in said operation b), a ratio of the amount of substance of LidAeOf to a total of the amount of substance of LiaMbXc and the amount of substance of LidAeOf is lower than or equal to 85%.

A method of producing a solid electrolyte, comprising:

• a) preparing a first compound that is LiX, a second compound that is MX3, and a third compound composed of Li, A, and O, where X is a halogen element, M is an element serving as a trivalent cation, and A is a sulfur element or a phosphorus element;
• and
• b) subjecting said first compound, said second compound, and said third compound to a mechanical milling process,
• wherein, in said operation a), 0.8c≤(a+3b)≤1.2c and 1.6f≤(d+n×e)≤2.4f are satisfied when a ratio of the amounts of substance of Li, M, and X in a mixture of said first compound and said second compound and the amounts of substance of Li, A, and O in said third compound is expressed as a:b:c:d:e:f by using values a to f that are greater than 0, where when A is a sulfur element, n is 4 or 6, and when A is a phosphorus element, n is 5, and
• 0<e/(c+e)≤0.5 is further satisfied.