Secondary battery and capacitor utilizing indole compounds

1. A capacitor having 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.

2. The capacitor as claimed in claim 1 , wherein the receipt and release of electrons in accordance with the oxidation-reduction reaction of the trimer compound are carried out only by the bonding and elimination of the proton bonded to the trimer compound.

3. The capacitor as claimed in claim 1 , wherein the trimer compound is represented by the following general formula(1):

wherein each R represents a hydrogen atom or a substituent, independently.

4. The capacitor as claimed in claim 1 wherein the electrode contains 30 wt % to 95 wt % of the trimer compound.

5. The capacitor as claimed in claim 1 comprising a solution containing 10 −3 mol/l to 18 mol/l of proton as the electrolyte.

6. A capacitor comprising:

a first electrode with a first electrode active material;

a second electrode with a second electrode active material; and

an electrolyte intermediate between the first electrode and the second electrode, the electrolyte including a proton source material;

wherein the first electrode active material and the second electrode active material undergo a reversible oxidation-reduction reaction, and

both or one of the first and second electrode active materials comprise 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.