HIGH-ELASTICITY PHOSPHAZENE POLYMER FOR LITHIUM METAL PROTECTION, LITHIUM SECONDARY BATTERY AND MANUFACTURING METHOD

A lithium secondary battery comprising a cathode, an anode, and an elastic polymer protective layer disposed between the cathode and the anode, and a working electrolyte in ionic communication with the anode and the cathode, wherein the elastic polymer protective layer comprises a high-elasticity polymer having a thickness from 2 nm to 200 μm, a lithium ion conductivity from 10S/cm to 5×10S/cm at room temperature, and a fully recoverable tensile elastic strain of at least 5% when measured without any additive or filler dispersed therein and wherein the high-elasticity polymer comprises a crosslinked polymer network of chains derived from a phosphazene compound and wherein the crosslinked polymer network of chains is impregnated with from 0% to 90% by weight of a liquid electrolyte.