Poly(ethylene glycol) electrolyte gels were prepared by condensation reaction in the presence of tetraethoxysilane. Differential scanning calorimetry and X-ray diffraction spectroscopy were used to investigate the thermal transition behavior and crystalline structure of polymer gels prepared. Both formation of crosslinks and incorporation of salts or plasticizers reduced the development of crystalline structure of poly(ethylene glycol)s. Cyclic voltammetric and ion-conducting behaviors of polymer gets were analyzed using potentiostat and impedance spectroscopy, and those were also considerably affected by the crosslinking density of polymers and the concentration of electrolyte salt or plasticizers incorporated. Poly(ethylene glycol) gels possessing certain levels of electrolyte salt and plasticizer were expected to have applications of solid electrolytes for lithium polymer secondary batteries.