Trifunctional carbosilanes containing hydroxy and cyano groups have been synthesized in good yields and incorporated into polyether-based electrolytes. The new linear and cross-linked modified PEOs have been characterized by DSC and conductivity measurements. The effect of silane content, the length of the PEO block, glycerol concentration, and temperature on glass transition temperature and conductivity of lithium salts complexes of these materials has been evaluated. The new materials showed improved conductivity (similar to 10(-5) S cm(-1)) at ambient temperatures compared with unmodified polyethers.