Abstract: A secondary battery of a proton conductive polymer, wherein a positive electrode and a negative electrode are arranged facing to each other via a separator in an electrolyte and only a proton or a proton of a hydroxyl group in an indole trimer and a &pgr; conjugated polymer, i.e., an active material of electrode in the positive electrode and in the negative electrode participates in a charge/discharge, and a proton concentration is 5 to 40% and an anion concentration is 30 to 60% in the solution, respectively, and the anion concentration is at least higher than the proton concentration.

Abstract: A secondary battery of a proton conductive polymer, wherein a positive electrode 2 and a negative electrode 4 are arranged facing to each other via a separator in an electrolytic solution and only a proton in a &pgr; conjugated polymer or a proton of a hydroxyl group in a hydroxyl-containing macromolecular as an active material of an electrode in the positive and negative electrodes participates in a charge/discharge; the secondary battery uses a membrane, which has acid resistance, oxidation resistance and a functional group having cation exchange function, as the separator 3.

Abstract: The present invention provides a secondary battery and a capacitor which may provide an excellent high rate and cycle characteristic as well as sufficient electromotive force and capacity. The secondary battery and a capacitor have an active material of an electrode comprising a trimer compound comprising three units of indole or indole derivatives in condensed ring form, wherein the second position and the third position of each unit form a six-membered ring, and a proton which can be utilized as a charge carrier of the trimer compound.