SOLID-STATE BATTERY, COMPOSITE POLYMER ELECTROLYTE, AND METHOD

Solid-state batteries, composite polymer electrolytes, and methods associated therewith. Such a composite polymer electrolyte includes high-entropy oxide particles and anion salt mixed in an amorphous polymer matrix. The polymer matrix may be made from a blend of a flexible, high melting point amorphous polymer, such as epoxidized natural rubber, and a semicrystalline polymer, such as polyethylene oxide. The solid-state battery may be a lithium-ion battery incorporating the composite polymer electrolyte with LiTFSI as the anion salt. The loading of the high-entropy oxide particles in the polymer matrix can be adjusted to adjust the ion conductivity of the composite polymer electrolyte.