Facile synthesis of crumpled-paper like CoWO4-CoMn2O4/N-doped Graphene hybrid nanocomposites for high performance all-solid-state asymmetric supercapacitors

Abstract

In this work, for the first time, the synergetic effect of CoWO4-CoMn2O4/N-doped graphene (CCNG) hybrid nanocomposites as active electrode materials with high conductivity and fast transmission of electrons/ions are investigated for high performance supercapacitor. The crumpled- paper like CCNG nanostructure is synthesized by an efficient and simple hydrothermal route via adding a certain amount of CoWO4-CoMn2O4 and a defined amount of urea as a reducing agent into the aqueous dispersion of graphene oxide (GO). The obtained CCNG hybrid nanocomposites represent excellent electrochemical efficiencies with a high specific capacitance of 4133.3 F g−1 at a current density of 2 A g−1. Besides, the proposed electrode exhibits the excellent specific energy density of 116.25 WhKg−1, specific power density of 2250 Wkg−1 and superior cycling stability by retaining 96.96% of their original capacitance after 5000 cycles. Furthermore, using CCNG as positive electrode and activated carbon (AC) as negative electrode is designed for an asymmetric supercapacitor (ASC). The assembled ASC device provides a superior specific capacitance of 281.58 mF g−1 at the applied current density of 1 mA g−1 and delivers the energy density of 56.31 mWh kg−1 at the power density of 600 mWkg−1.