3D architecture of a graphene/CoMoO(4) composite for asymmetric supercapacitors usable at various temperatures

Abstract

Designing and optimizing the electrode materials and studying the electrochemical performance or cycle life of the supercapacitor under different working conditions are crucial to its practical application. Herein, we proposed a rational design of 3D-graphene/CoMoO₄ nanoplates by a facile two-step hydrothermal method. Owing to the high electron transfer rate of graphene and the high activity of the CoMoO₄ nanoplates, the three-dimensional electrode architectures achieved remarkable electrochemical performances with high areal specific capacitance (1255.24F/g at 1A/g) and superior cycling stability (91.3% of the original specific capacitance after 3000 cycles at 1A/g). The all-solid-state asymmetric supercapacitor composed of 3D-graphene/CoMoO₄ and activated carbon (AC) exhibited a specific capacitance of 109F/g at 0.2A/g and an excellent cycling stability with only 12.1% of the initial specific capacitance off after 3000 cycles at 2A/g. The effects of temperature and charge-discharge current densities on the charge storage capacity of the supercapacitor were also investigated in detail for practical applications.

Keywords: 3D-graphene; Asymmetric supercapacitor; High specific capacitance; Various temperatures.