An acidic cellulose-chitin hybrid gel as novel electrolyte for an electric double layer capacitor

Abstract A novel acidic cellulose–chitin hybrid gel electrolyte including binary ionic liquids (ILs) with an aqueous H 2 SO 4 solution was prepared for an electric double layer capacitor (EDLC). Its electrochemical characteristics were investigated by galvanostatic charge–discharge measurements. The test cell with a hybrid gel electrolyte shows a specific capacitance of 162 F g −1 at room temperature, which is higher than that for a cell with an H 2 SO 4 electrolyte, 155 F g −1 . This hybrid gel electrolyte exhibits excellent high-rate discharge capability in a wide range of current densities as well as an aqueous H 2 SO 4 solution. The discharge capacitance of the test cell can retain over 80% of its initial value in 100,000 cycles even at a high current density of 5000 mA g −1 .