Temperature Dependence of Electric Double-Layer Capacitor Operation Utilizing Acidic Cellulose-Chitin Hybrid Gel Electrolytes

Abstract

An acidic cellulose-chitin hybrid gel electrolyte consisting of cellulose, chitin, 1-butyl-3-methylimidazolium, 1-allyl-3-methylimidazolium bromide, and an aqueous H2SO4 solution is investigated for electric double layer capacitors (EDLCs). This gel electrolyte shows a high ionic conductivity comparable to that observed in an aqueous 2 mol dm-3 H2SO4 solution. An EDLC cell with the acidic hybrid gel electrolyte has higher capacitance than that with an aqueous H2SO4 solution in the operation temperature. Moreover, the capacitance retention of the EDLC cell with the acidic hybrid gel electrolyte is better than a cell with a H2SO4 solution over 10,000 cycles. This suggests that the present acidic gel electrolyte has excellent stability in the presence of a strong acid even at a high temperature.