The use of ionic liquids in polymer gel electrolytes

Polymer gel electrolytes composed of 1,2-dimethyl-3-n-alkylimidazolium bis-trifluoromethanesulfonylimide (alkyl = propyl or butyl) and polyvinylidenedifluoro-hexafluoropropylene are characterized by ac-impedance and cyclic voltammetry. Two electrode charge-discharge experiments were also performed using graphitic paper or Li metal as the anode, and polymer composites of LiMn2O4, LiCoO2, or V2O5 as cathodes. Results indicated that the polymer composite gel electrolytes were stable for over 50 cycles when used in direct contact with Li metal. High efficiencies and low voltage drop-offs indicate that polymer gel composite electrodes composed of these ionic liquids are a viable alternative to the more common organic solvent electrolytes.