Transition Metal Oxides as Supercapacitor Materials

Abstract

Transition metal oxides attract considerable attention in the field of energy storage/conversion not only because of their beneficial reported mechanical, structural, or electronic properties but also due to their high pseudocapacitances ascribed to their multiple valence state changes which is generally not possible via carbon materials. Typically, transition metal oxides utilized as supercapacitor materials can be classified into noble transition metal oxides such as RuO2 and IrO2 and base transition metal oxides including MnO2, NiO, Co3O4, NiCo2O4, etc. Alternatively, base transition metal oxides are considerably cheaper and more environmentally friendly than noble transition metals as well as exhibiting excellent capacitive properties, which have become a new research hotspot in recent years. This chapter briefly analyzes the energy storage mechanism of transition metal oxides, summarizes the methodologies and nanostructures prospering in recent years, and points out the potential problems and prospects of utilizing transition metal oxides as the basis of supercapacitors.