SOLID ELECTROLYTE AND BATTERY

A solid electrolyte contains: an electrolyte solution containing a lithium salt and a carbonate solvent; and metal oxide particles. In the solid electrolyte, the lithium salt is at least one selected from lithium-bis(fluorosulfonyl)imide and lithium borofluoride, the carbonate solvent is at least one selected from dimethyl carbonate and propylene carbonate, a molar ratio (lithium salt/carbonate solvent) of the lithium salt to the carbonate solvent is in a range from 1/4 to 1/1, a mass ratio (electrolyte solution/metal oxide particle) of the electrolyte solution to the metal oxide particles is in a range from 72/28 to 93/7, and a specific surface area of the metal oxide particles measured by a BET method is in a range from 160 m2/g to 700 m2/g.