Novel polymeric ionic liquid membranes as solid polymer electrolytes with high ionic conductivity at moderate temperature

A series of guanidinium polymeric ionic liquid (PIL) electrolyte membranes combining different anions, such as BF4-, PF6-, ClO4- and N(CF3SO2)(2)(-), were synthesized through copolymerization and anion exchange reaction as new promising solid polymer electrolytes. The chemical structures of the PILs were characterized by H-1 NMR and ATR-FT IR spectra, and their thermal properties, ionic conductivity and electrochemical stability were evaluated, respectively. The PILs present different decomposition temperature and glass transition temperature (T-g), and their thermal properties strongly depend on the sort of anions. The 1g2-MA-BF4 possesses the better thermal stability and it decomposes at 353 degrees C. The 1g2-MA-TFSI shows the lower T-g and it is below -60 degrees C. The ionic conductivity of the PIL electrolytes depends on the lithium salts used and its content. The best ionic conductivity of the PILs electrolyte 1g2-MA-BF4/LiBF4 (30 wt%) was 1.35 x 10(-4) S cm(-1) at 30 degrees C. (C) 2010 Elsevier B.V. All rights reserved.