Polycationic oxides as potential electrode materials for aqueous-based electrochemical capacitors

Summary Since the early use of RuO2-based electrodes in electrochemical capacitors, so called supercapacitors, metal oxides have always attracted much attention as pseudocapacitive electrode materials for such energy storage devices. Although the literature is well documented about electrode materials based on single metal oxides, polycationic oxides have also drawn some attention upon the last five years. It is however still quite difficult to build a pertinent strategy to design polycationic architectures that can provide at the same time pseudocapacitive behavior, high capacitance and long term cycling efficiency. This review aims at providing more insight into these polycationic oxide materials as potential electrode materials for supercapacitors.