2 2 2 NEGATIVE ELECTRODE FOR POTASSIUM ION SECONDARY BATTERIES NEGATIVE ELECTRODE FOR POTASSIUM ION CAPACITORS POTASSIUM ION SECONDARY BATTERY POTASSIUM ION CAPACITOR AND BINDER FOR NEGATIVE ELECTRODES OF POTASSIUM ION SECONDARY BATTERIES OR NEGATIVE ELECTRODES OF POTASSIUM ION CAPACITORS

摘要

The present invention provides a potassium ion secondary battery or a potassium ion capacitor and a cathode thereof that do not readily deteriorate in charge / discharge capacity even if charging / discharging is repeated, and have a long life as a secondary battery. A negative electrode for a negative electrode or a potassium ion capacitor for a potassium ion secondary battery, which contains a carbon material capable of occluding and releasing potassium and a binder containing a polycarboxylic acid and / or a salt thereof. A secondary battery comprising the cathode or the capacitor. A binder for a potassium ion secondary battery anode or a potassium ion capacitor cathode comprising a polycarboxylic acid and / or a salt thereof.