The Research On The Supercapacitor Rerformance Of ZnCo₂O₄/MnMoO₄ Core-shell Material

Electrochemical energy storage technology in the renewable energy storage system has been rapid development Super capacitor as a new type of energy,because of its high power density and good cycle stability of people's attention But because of the low energy density,capacitance value is still far from people's expectations,its is still limited in the actual application Constraint capacitor is based on Faraday reaction as the main mechanism,through the electrode material with a redox active electrode surface or internal reversible redox reaction quickly Constraint capacitor electrode material generally fall into the transition metal oxides and conductive polymer and metal oxide because of its rich features such as redox reaction,has become the most potential of super capacitor electrode materials.Among them,the ternary transition metal oxides showed more quickly than binary transition metal oxides redox reaction of higher electrochemical activity and has more research value Multiple transition metal oxides,ZnCo₂O₄because of its performance in the field of super capacitor with high specific capacity of the environment friendly and morphological diversity has been widely studied However,due to its low intrinsic conductivity,ZnCo₂O₄electrode has a low rate performance.In recent years,MnMoO₄has improved the performance of supercapacitors with excellent interfacial reaction kinetics and diffusion kinetics of electronic conductivity,especially in specific capacitance and rate performance Therefore,on the premise of not sacrificing the cyclic stability and electric storage performance of zinc cobalate electrode material,chose MnMoO₄and ZnCo₂O₄composite to assemble a hybrid capacitor with excellent electrochemical performance.My research content is as follows:1.Two kinds of ZnCo₂O₄electrode materials with microsphere and microflower morphology were prepared by simple hydrothermal method and subsequent heat treatment.Meanwhile,the electrochemical properties of the electrode materials were systematically studied by using A three-electrode system.The results show that the current density is 3 A g^-1in 6 M KOH electrolyte,the specific capacities of the two ZnCo₂O₄electrodes are 1207.9 F g^-1and 1373.7 F g^-1,respectively.When the current density gradually increases from 5 A g^-1to 50 A g^-1,the capacitive retention is 65.6%and 69.3%,respectively,at 10 A g^-1current density,the capacitance retention rate is82.9%,85.2%after 3000 cycles of charging/discharging.2.In order to further improve the electrochemical properties of ZnCo₂O₄electrode,ZnCo₂O₄/MnMoO₄composite materials with two different morphologies were prepared by the second hydrothermal reaction of ZnCo₂O₄with two different morphologies as the skeleton and MnMoO₄nanosheets The specific capacitance values of ZnCo₂O₄/MnMoO₄spherical core-shell structure and ZnCo₂O₄/MnMoO₄flower-like core-shell structure in the three-electrode system are as high as 2347.4 F g^-1and 2873.7F g^-1at the current density of 3 A g^-1,respectively Based on the synergistic effect of the two metal oxide electrode materials,ZnCo₂O₄micron flower 1.9 times and 2 times exhibits high capacitance retention of 67.3%,74.5%at the current density increases from 3 A g^-1to 50 A g^-1After 3000 cycles of charge/discharge at 10 A g^-1,the capacitance retention can reach 86.5%and 89.1%,respectively.As a composite electrode,ZnCo₂O₄/MnMoO₄core-shell structure has higher specific capacitance and better rate performance.