Patent ID: 7226697

Claim:
A charge storage device wherein a positive electrode comprises a nitroxyl compound wherein the nitroxyl compound is a compound containing a cyclic structure represented by general formula (Ia) in an oxidized state: wherein R 1 to R 4 independently represent alkyl having 1 to 4 carbon atoms; and X represents a bivalent group forming a five-to seven-membered ring; provided that Formula (Ia) is a low molecular weight compound or Formula (Ia) is a part of a polymer where X is a part of a side chain in the polymer or X is a part of the main chain of the polymer; and provided that the nitroxyl compound has a structure of a nitroxyl cation moiety represented by formula (I) in an oxidized state and has a structure of a nitroxyl radical moiety represented by formula (II) in a reduced state