Secondary battery and method of generating electric power

A secondary battery comprising a power generating part and a charging part, wherein €ƒ€ƒ€ƒ the power generating part comprises an acidic medium in which a first electrode is disposed and a basic medium in which a second electrode is disposed; €ƒ€ƒ€ƒ the acidic medium and the basic medium are disposed adjacent to each other; €ƒ€ƒ€ƒ at least one of the acidic medium or the basic medium includes at least one reactive substance; and €ƒ€ƒ€ƒ the charging part comprises a reactive substance regenerating device which regenerates the reactive substance from power-generation products produced by electric power generation in the power generating part.