Montmorillonite clay was modified with four kinds of quaternary alkylammonium salts to enable the intercalation of polyacrylonitrile (PAN) into the resulting organophilic clay in PC/EC cosolvents. X-ray diffraction experiments revealed that PAN was able to intercalate in the clay galleries. The exfoliation and intercalation phenomena were also confirmed by transmission electron microscopy. A series of gel PAN/clay nanocomposite electrolyte materials were successfully prepared by incorporating appropriate fractions of PAN, organophilic clay, PC/EC cosolvent, and LiClO4. The PAN/clay nanocomposite electrolyte shows a maximum ionic conductivity of 1.4 x 10(-2) S/cm and exhibits superior ability in film formation and plasticizer absorption, and dimensional stability in comparison to the electrolyte that contains no organophilic clay. Cyclic voltammetric data indicated that the addition of organophilic clay significantly enhances the electrochemical stability of the composite electrolyte system.