Ultrafast Self‐Assembly of Graphene Oxide‐Induced Monolithic NiCo–Carbonate Hydroxide Nanowire Architectures with a Superior Volumetric Capacitance for Supercapacitors

Abstract

The monolithic electrodes with high volumetric capacitance demonstrate a great potential in practical industrial applications for supercapacitors. Herein, a novel strategy for ultrafast self‐assembly of graphene oxides (GO)‐induced monolithic NiCo–carbonate hydroxide (NiCo–CH) nanowire composite films (G–CH) is reported. The oxygen‐containing functional groups on the GO surface help effectively to induce formation of the monodisperse NiCo–CH nanowires. Such a nanowire‐shaped structure further functions as a scaffold and/or support, leading to 25 s of ultrafast self‐assembly for G–CH composite films and a relatively loose and open channel that contributes to fast electrolyte transport. The as‐obtained monolithic G–CH architectures show an excellent supercapacitor performance as binder‐ and conductive agent‐free electrode, evidenced by a superior volumetric capacitance of 2936 F cm−3 and good electrochemical stability. Combining highly conductive carbon nanotubes (CNTs) into the monolithic composite films can further create well‐interconnected conductive networks within the electrode matrix, thus to improve the reaction kinetics and rate capability. The present strategy that can modulate the growth of the high‐electroactive pseudocapacitive hydroxides and achieve an ultrafast self‐assembly of monolithic composites may pave a promising new way for development of high‐performance supercapacitors and shed a new light on the configuration of carbon‐based electrode materials in energy storage and conversion devices.