Electrochemical Studies of Composited Cellulose Polymer Gel Electrolytes for

ABSTRACT: Polymer gel electrolyte was obtained by gelling lithium triflate dissolved in dimethyl formamide using cellulose acetate as polymer, while composite polymer gel electrolyte was obtained from the dispersion of silicon dioxide in the polymer gel electrolyte. To prepare gel electrolytes, liquid electrolyte solutions (dimethyl formamide + lithium triflate) of different molarities were formulated, to which different concentrations of cellulose acetate were added along with stirring for 24 hours at room temperature. For polymer gel composites, silicon dioxide was dispersed in polymer gel electrolytes with the highest conductivity in order to further improve their conductivity and mechanical properties. The addition of polymer to liquid electrolytes resulted in an increase in viscosity and an overall decrease in conductivity measured by impedance spectroscopy. However, at some definite concentration of cellulose acetate, the conductivity increased up to 5.99 x 10-3 S cm-1, which has been explained by the “Breathing Polymeric Chain Model”. A further increase in conductivity was noted at selected concentrations of dispersed silicon dioxide in polymer gel electrolyte composites. The best conductivity and mechanical stability of the composite polymer gel electrolyte obtained from these experiments were used for the fabrication of a lithium-air battery with the configuration Lithium/composite polymer gel electrolyte/Air-cathode. Results of linear sweep voltammetry of the highest composite polymer gel electrolyte revealed that the sweep could be extended up to 4.00 V. The specific capacity of the Li-air cells amounts to 241.7 mAh g-1 of th