METHOD OF IMPROVING THE CYCLE STABILITY AND ENERGY DENSITY OF A LITHIUM METAL SECONDARY BATTERY

The invention provides a method of improving the cycle-life of a lithium metal secondary battery containing a non-solid state electrolyte, the method comprising implementing an anode-protecting layer between an anode active material layer and a cathode active material layer without using a porous separator, wherein the anode-protecting layer is in a close physical contact with the anode active material layer, has a thickness from 1 nm to 100 μm and comprises an elastomer having a fully recoverable tensile elastic strain from 2% to 1,000% and a lithium ion conductivity from 10S/cm to 5×10S/cm when measure at room temperature and wherein the anode active material layer contains a layer of lithium or lithium alloy, in a form of a foil, coating, or multiple particles aggregated together, as an anode active material.