Polymer electrolyte compositions for lithium electrochemical generators of the LPB type (lithium polymer electrolyte battery), comprising a mixture of polymers wherein one of the components has a high molecular weight, such as those used currently in LPB batteries, and wherein the other component is a low molecular weight polymer resulting in a more efficient and faster multi-dimensional cross-linking by irradiation, so as to give a network which is interpenetrated or not and films of electrolyte being have better mechanical properties and lower thicknesses, while preserving the good properties of adhesion on the electrodes and the choice of the coating techniques.