Provided is cathode active material layer for a lithium battery. The cathode active material layer comprises multiple cathode active material particles and an optional conductive additive that are bonded together by a binder comprising a high-elasticity polymer having a recoverable tensile strain from 5% to 700% (preferably from 10% to 100%) when measured without an additive or reinforcement in said polymer and a lithium ion conductivity no less than 10−5 S/cm (preferably and typically from 1.0×10−5 S/cm to 5×10−2 S/cm) at room temperature.