High-Energy-Density\nSupercapacitors from Dual Pseudocapacitive\nNanoelectrodes

Abstract

Supercapacitors\nfeature high power densities but low energy densities.\nTo further improve the energy densities of supercapacitors, it is\nimportant to design and synthesize new electrode materials. The performance\nmatch of the used anode and cathode is also required for the construction\nof supercapacitors with both high power densities and energy densities.\nIn this work, two redox-active electrode materials are synthesized:\nbimetallic Ni–Co hydroxide/oxide hydroxide nanosheets-coated\nholey reduced graphene oxide (hrGO) and rGO-supported Fe₂O₃ nanorods. They are further employed as the cathode\nand the anode to construct a dual pseudocapacitor, respectively. After\nmatching the performance of two electrodes, the as-assembled supercapacitor\ndevice features a cell voltage of 1.6 V. It exhibits an energy density\nof 91.1 Wh kg^–1 at a power density of 800.0 W kg^–1 and a long cycling life. Its power density can reach\n24008.1 W kg^–1 when a current density of 30 A g^–1 is applied. Therefore, this kind of dual pseudocapacitor\nis an efficient energy storage device and can be utilized as a promising\nenergy supplier for different applications.