Preparation and supercapacitive properties of MgCo2O4@Ni(OH)2 nanoneedles
MgCo2O4@Ni(OH)2(MCON)electrode material for supercapacitors was succeessfully prepared by hydrothermal and electrodeposition in this work.Nanoneedle MgCo2O4 was coated with cotton-shaped Ni(OH)2 on the conductive substrate of foam nickel,improving the structure of main material and constituting an effec-tive electrical connection,thus enhancing the electrical conductivity.Electrochemical performance tests showed that this MCON exhibited excellent electrochemical properties,and it revealed a high specific capacitance of 2 635.4 F/g at a current of 1 mA/cm2,indicating its canapcitance was increased by 72.4％.After 1 000 cycles under the condition of 14 mA/cm2,91.2％of initial capacitance was retained.Asymmetric supercapacitor was assembled with MCON as binder-free positive electrode and activated carbon as negative electrode respectively,which displayed a specific capacitance of 91.8 F/g at 1 A/g.Besides,asymmetric supercapacitor showed energy density of 28.7 Wh/kg under the power density of 2.1 kW/kg.Meantime,a red light-mitting diode could remain lit for 25 min.The above results show that designing composite has a strong ability to energy storage,suitable as a supercapacitor electrode material.
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