The field of the present invention relates to the field of batteries and of polymer electrolytes for batteries and more particularly to the field of lithium batteries.The invention relates to a composition which can be polymerized and/or crosslinked by dehydrocondensation for a battery electrolyte comprising: a) at least one organohydropolysiloxane (POS) (A) having, per molecule, at least 2 hydrogen atoms directly bonded to silicon atoms; b) at least one organohydroxypolysiloxane (POS) (B) having, per molecule, at least 2 —OH groups directly bonded to silicon atoms; c) an effective amount of a dehydrocondensation catalyst (C); and d) at least one electrolyte salt (D); with the condition that the POS (A) and/or the POS (B) comprise(s), per molecule, at least one siloxyl unit comprising at least one group directly bonded to a silicon atom comprising a polyoxyalkylene (Poa) ether functional group.