Disclosed is a nonaqueous and nonvolatile liquid type polymeric electrolyte comprising poly(siloxane-g-ethylene oxide). This electrolyte provides significant safety and stability. The present invention solves the problems of volatility, flammability and chemical reactivity of lithium ion type electrolytes. The disclosed electrolyte exhibits excellent stability, conductivity and low impedance characteristics. The electrolyte comprises a new class of structural siloxane polymers with one or more poly(ethylene oxide) side chains. The inorganic siloxanes comprising the main backbone of the copolymers are thermally very stable and resistant to decomposition by heat. Because the main chain of the disclosed class of electrolytes is an Si--O linkage, initiation of the combustion cycle is inhibited or prevented.