CAPACITOR AND METHOD FOR CHARGING AND DISCHARGING SAME

摘要

A capacitor includes a positive electrode, a negative electrode, a separator disposed between the positive electrode and the negative electrode, and an electrolyte. The positive electrode includes a positive electrode current collector and a positive electrode active material held on the positive electrode current collector. The positive electrode active material contains activated carbon. The activated carbon has a carboxyl group, and an amount of desorption of carboxyl group per unit mass of the activated carbon is 0.03 µmol/g or less when the activated carbon is heated with a temperature increase from 300°C to 500°C. The capacitor has an upper-limit voltage V u for charging and discharging. The upper-limit voltage V u of a lithium-ion capacitor is 4.2 V or more. The upper-limit voltage V u of an electric double-layer capacitor is 3.3 V or more.