Negative electrode for potassium ion secondary battery or negative electrode for potassium ion capacitor, potassium ion secondary battery or potassium ion capacitor and binder for negative electrode of potassium ion secondary battery or negative electrode for potassium ion capacitor

摘要

To provide a potassium ion secondary battery or a potassium ion capacitor, and a negative electrode thereof, in which charge / discharge capacity is not easily deteriorated even after repeated charge / discharge, and has a long life as a secondary battery. A negative electrode for a potassium ion secondary battery or a negative electrode for a potassium ion capacitor, comprising a carbon material capable of inserting and extracting potassium and a binder containing polycarboxylic acid and / or a salt thereof. A potassium ion secondary battery comprising the negative electrode or capacitor. Binder for potassium ion secondary battery negative electrode or potassium ion capacitor negative electrode containing polycarboxylic acid and / or its salt.