Study on capacitor performance of high-mass-loading ZnCo-based carbonate hydroxide electrode materials
Rational design of electrode material structure is a key factor to improve high capacity,energy density,power density and long lifetime of supercapacitors.The ZnCo-based alkaline carbonate nano-arrays with high loading were grown in situ on nickel foam mesh by a similar two-step hydrothermal method,and the effects of the feeding ratio of metal ions on the microscopic morphology,the crystalline shape of the phases,and the electrochemical performance of the electrode mate-rials were investigated.The test results showed that when n(Zn)∶n(Co)=1∶4,the resulting ZnCo-based alkaline carbonate electrode materials exhibited an upright-grown nanosheet array structure,and the nanosheet structure could provide a large specific surface area,while the large spacing between neighboring nanosheets ensured open electrolyte ion mass transfer channels,which enabled excellent charge storage capacity and good cycling stability.At a current density of 10 mA/cm2,the sample area specific capacitance was 3.08 C/cm2 and it was stably tested for 15 000 cycles at high current.Moreover,the as-assembled supercapacitor with Zn0.25Co-CH electrode and activated carbon(AC)negative electrode could be oper-ated at a large voltage window of 0～1.8 V,and delivered an energy density of 0.69 mW·h/cm2 at the power density of 9 mW/cm2.Moreover,the device exhibited an outstanding cycle stability,while the capacity retention after 10 000 cycles was 92.1% .
ZnCo-based carbonate hydroxidehigh mass loadingsupercapacitorcyclic stability
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