CAPACITOR AND METHOD FOR CHARGING AND DISCHARGING SAME

摘要

This capacitor comprises a positive electrode, a negative electrode, a separator that is interposed between the positive electrode and the negative electrode, and an electrolyte. The positive electrode comprises a positive electrode collector and a positive electrode active material that is supported by the positive electrode collector. The positive electrode active material contains activated carbon, and this activated carbon has a carboxyl group. The desorption amount of carboxyl groups per unit mass of the activated carbon if heated from 300°C to 500°C is 0.03 μmol/g or less. This capacitor has an upper limit voltage (Vu) for charging and discharging. The upper limit voltage (Vu) of a lithium ion capacitor is 4.2 V or more, while the upper limit voltage (Vu) of an electric double layer capacitor is 3.3 V or more.