Novel solid polymer electrolytes containing group 13/III metal alkoxides having Lewis acidity have been synthesized by hybridization of polymer from methoxy poly(ethylene glycol) monomethacrylate, B {(OC2H4)(12)OCH3}(3) or Al(OC2H5)3 or Ga(OC2H5)(3), and LiCl; the resulting solid polymer electrolyte containing Ga(OC2H5)(3) exhibited a conductivity of one order higher than that of alkoxide-free electrolyte.