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

A novel acidic cellulose–chitin hybrid gel electrolyte including binary ionic liquids (ILs) with an aqueous H₂SO₄ 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 H₂SO₄ 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 H₂SO₄ 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.