Effect of the polymer host, Polyacrylonitrile on the performance of Li rechargeable cells

Abstract

Gel electrolytes have emerged as potential candidates for various applications because they have appreciable ionic conductivities while having mechanical stability. In this study, the main objective was to find the role of Polyacrylonitrile (PAN) on performance of a gel polymer electrolyte in a Li rechargeable cell. A gel electrolyte was prepared using Ethylene Carbonate (EC), Propylene Carbonate (PC) and Lithium Trifluoromethanesulfonate (LiCF 3 SO 3 ) with PAN. A Li rechargeable cell having a conducting polymer cathode was assembled with the electrolyte. To observe the effect of PAN, parent liquid electrolyte was also used in a similar cell. It was seen that both cells have equal capacities but the stability with a liquid electrolyte is very low. This means PAN provides only dimensional stability. Room temperature conductivity of few samples was measured varying PAN amount. When PAN amount was increased, conductivity reduced. It may be due to blocking of ion transporting channels. It was interested to note that both gel electrolyte and its liquid electrolyte show maximum conductivity at slightly different salt concentrations for many temperatures. We conclude that addition of PAN does not disturb the performance of gel electrolyte in a battery; But it provides the mechanical stability for the liquid electrolyte. Keywords : Polyacrylonitrile; Ionic conductivity; Gel Polymer Electrolyte; Lithium Trifluoromethanesulfonate; Liquid Electrolyte DOI: http://dx.doi.org/10.4038/sljp.v12i0.4096 Sri Lankan Journal of Physics, Vol. 12 (2011) 25-31