Provided is lithium secondary battery comprising a cathode, an anode, and an electrolyte or separator-electrolyte assembly disposed between the cathode and the anode, wherein the anode comprises: (a) a foil or coating of lithium or lithium alloy as an anode active material; and (b) a thin layer of a high-elasticity polymer having a recoverable tensile strain no less than 5%, a lithium ion conductivity no less than 10−6 S/cm at room temperature, and a thickness from 1 nm to 10 μm, wherein the high-elasticity polymer contains an ultrahigh molecular weight polymer having a molecular weight from 0.5×106 to 9×106 g/mole and is disposed between the lithium or lithium alloy and the electrolyte or separator-electrolyte assembly.