Ionic conductivity studies on natural rubber grafted with 30% (MG30) doped lithium perchlorate (LiC1O₄) polymer electrolytes / Nur Rashidah Zainudin

In the present study, 30% PMMA-grafted-natural rubber (MG30), lithium perc hlorate (LiC1O₄) propylene carbonate (PC) and ethylene carbonate (EC) were used in the preparation of solid polymer electrolytes (SPE) and gel polymer electrolytes (GPE). All sample were prepared by solution cast technique. SPE and GPE were characterized by means of physical and electrical spectroscopy in order to find the suitable polymer electrolytes composition for fabrication in lithium polymer cell. The conductivity of all samples was calculated using the bulk resistance value obtained from the complex impedance plot in the frequency range 100Hz to 1 MHz. The SPE film containing 20 wt.% LiC1O₄ in MG30: (LiC1O₄) exhibit the highest conductivity of 1.865 x 10~8 S cm-1 at room temperature. A further enhancement in the conductivity was obtained on plasticization to form the GPE. The highest room temperature conductivities of 4.12 x 10-4 S cm-1 LiC1O₄:MG30 : PC : EC systems. The increase in conductivity observed in the GPE is due to the increase in the number of mobile ions that is associated with conformational free volume and flexibility of the polymer host upon introduction of plasticizer. The highest GPE for ambient temperature is 2.2 x 10⁻ᶟ S cm⁻¹. at 70 degree celcius.