Disclosed are a single-ion capacitor, a micro-capacitor and an ion capacitor. Under the action of an electric field, a single water molecule serves as a medium, and a capacitor formed by locating a single positive ion and a single negative ion at two ends of the single water molecule serves as the single-ion capacitor. A rock particle wrapped by a water film serves as a medium, and a capacitor formed by locating a single layer of positive ions and a single layer of negative ions at two ends of the rock particle wrapped by the water film serves as the micro-capacitor. The ion capacitor includes the single-ion capacitor and the micro-capacitor.
