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

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.This work was supported by the Global Frontier R&D Program (2013M3A6B1078874) on Center for Hybrid Interface Materials (HIM) funded by the Ministry of Science, ICT & Future Planning, by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (2013R1A1A2007365 and 2014R1A1A2055740), and by the Start-up Research Grant (SRG2015-00057-FST) from Research & Development Office at University of Macau