Applicability of natural rubber based polymer electrolyte for electrochemical double layer capacitors

Natural rubber has received a great interest to be used for electrochemical applications recently. But, Sri Lankan natural rubber has not yet been considered for such activity other than exporting and using for some manufacturing processes. Main objective of the present study is investigating the candidacy of Sri Lankan natural rubber in electrochemical double layer capacitors. Methyl grafted natural rubber was dissolved in tetrahydrofuran and it was later mixed with a Li salt. Using the solvent casting method, it was possible to prepare a thin, bubble free film. It was sandwiched in between two identical Sri Lankan natural graphite electrodes. Performance evaluation was accomplished with cyclic voltammetry, electrochemical impedance spectroscopy and galvanostatic charge discharge test. Single electrode specific capacitance was depending on the potential window and the scan rate of cycling. Nyquist plots confirmed the capacitive behavior at low frequency region. The average specific discharge capacity was 0.31 Fg^-1. Obtained results show that natural rubber electrolytes are suitable candidates for electrochemical double layer capacitors and they are also encouraging to proceed towards improving the performance further.