Chapter 7 - Supercapacitors based on two-dimensional metal oxides, hydroxides, and its graphene-based hybrids

Abstract

The supercapacitor has been widely seen as one of the most promising emerging energy storage devices, by which energy will be stored in the form of chemical energy which is transformed from electrical energy/electricity. Two-dimensional (2D) metal oxides/hydroxides are exceptionally transforming the growth and design of ultrahigh performance supercapacitors because of their high theoretical specific capacitance, existence of stable and large number of electrochemically active sites, and feasibility for further assembly in hierarchical structures by integrating with allotropic forms of carbon, conductive polymers, and so on. The architectures/assembled network of 2D metal oxides/hydroxides can not only overcome the limitations of using an individual material but also bring new breakthroughs in performance from their synergetic cooperation at a large scale. In this chapter, the research progress on 2D metal oxide/hydroxides and their hybrids with carbon-based nanostructures as a supercapacitor materials are systematically studied, including the evolution of supercapacitor materials at nanoscale boundaries, the configurations of hybrid structures, the electrical properties regulated, and the existence of advantages and drawbacks other composite materials. Finally, a perspective covering directions and challenges related to the development of supercapacitor materials is also provided.