New composite polymer gels were obtained from cellulose triacetate (CTA), N-methyl-N'-propylpyrrolidinium bis(trifluoromethanesulfonyl)imide (Pyr(1,3)TFSI), and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI). Analysis by differential scanning calorimeter and scanning electron microscope showed that the ionic gel consisting of CTA, Pyr(1,3)TFSI, and LiTFSI formed a completely homogeneous phase at the molar ratio of CTA/Pyr(1,3)TFSI/LiTFSI = 1/3/1.5. The ionic conductivity of the polymer gel was significantly enhanced by the presence of LiTFSI. FTIR study strongly implies that the interaction of lithium ion with the carbonyl group of CTA could be responsible for the increase in conductivity. (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 115: 32-36, 2010