Facile Synthesis of Microsphere Copper Cobalt Carbonate Hydroxides Electrode for Asymmetric Supercapacitor

Abstract

Porous microspheres copper cobalt carbonate hydroxides (CuxCo2-xCH) pseudocapacitive electrode material comprised of nanoplates via a facile hydrothermal method were presented. Significantly, the crystalline structure, morphology and electrochemical performance of the CuxCo2-x,CH can be readily manipulated by varying the Cu/Co molar ratios. Among various stoichiometries of CuxCo2-xCH porous microspheres studied, Cu1.79Co0.21CH consisted of nanoplates with a mean thickness of similar to 35 nm showed a high specific capacitance of 789 Fg(-1) at a current destiny of 1 A g(-1) and good rate ability. Furthermore, the optimized Cu1.79Co0.21CH electrode also exhibited remarkable high cycling stability, ca 77.5% after 3000 charge/discharge cycles at current density of 5 Ag-1. An asymmetric device was constructed from optimized Cu1.79Co0.21CH materials on nickel foam (NF) as cathode electrode and graphene on NF as anode electrode in a 6M KOH electrolyte. The asymmetric Cu1.79Co0.21CH/NF//graphene/NF super-capacitor device delivered a specific capacitance of 60.5 Fg(-1) in a potential range of 0-1.6 V. A high energy density of 21.5 W h kg(-1) was achieved at the power density of 200 Wkg(-1). More significantly, the designed device exhibited excellent cycling stability with 73.3% capacity retention after 5000 cycles. (C) 2015 Elsevier Ltd. All rights reserved.