Effect of anion size on the conductivity behaviour of hexanoyl chitosan-based polymer electrolytes

Films of hexanoyl chitosan containing lithium perchlorate (LiClO4) or lithium triflouromethanesulfonate (LiCF3SO3) were prepared by solution casting technique. The effect of anion size on the conductivity behaviour of hexanoyl chitosan has been investigated. The conductivity of 4.15 x 10(-7) S/cm and 4.07 x 10(-6) S/cm were achieved for the hexanoyl chitosan-LiClO4 and hexanoyl chitosan-LiCF3SO3 electrolyte system at 50wt.% of salt concentration, respectively. The Rice and Roth model was used to analysis quantitatively the obtained conductivity trends for the prepared electrolyte systems. The diffusion coefficients of cations and anions were calculated from the conductivity and transference number measurements. This is followed by the discussion on the diffusion coefficients of ClO4- and CF3SO3- anion.