Study On The Modification Of ZnMn₂O₄ Of Electrode Material Of Supercapacitor

Supercapacitor is a hot topic in energy research in recent years.As a manganese base material,ZnMn₂O₄ has a high ratio of capacitance,low price and environmental friendliness.It is considered as a promising super capacitor electrode material.At present,the problem of manganese base materials is that the conductivity is low,the volume will expand,and the circulation performance is not good.In this paper,the solvent thermal method was used to modify the experimental operation by adding different surfactants,the coating structure of nickel oxide and the doping of cobalt element.The microstructure,energy band structure,optical properties and electrochemical properties of ZnMn₂O₄ were studied systematically by means of XRD,SEM,HRTEM,SAED,EDS,XPS,UV-vis,FT-IR and PL.The main research results are as follows:（1）Three structures of honeycomb,microsphere and flake clusters were prepared by adding different surfactants CTAB,PEG and Polysorbate.All samples are spinel structure with good crystallinity.ZnMn₂O₄ electrode material has excellent electrochemical reversibility and ideal capacitance in electrochemical tests.ZnMn₂O₄ electrode impedance is very small and long cycle test can maintain the energy storage efficiency above 92%.The sample with a PEG is the highest.（2）The nickel element is evenly distributed on the surface of ZnMn₂O₄,forming a nickel oxide coating on the surface of the spinel structure.And the surface Ni of ZnMn₂O₄ has a valence of+2 and+3.In the electrochemical test,the impedance value of the coated sample became smaller,and the specific capacitance value was significantly improved,and the long cycle energy storage efficiency was 98.8%.（3）Zn_1-xCo_xMn₂O₄ nanoparticles with different doping ratios were synthesized by solvent heat method.The shape of the sample is the spinel structure composed of hollow microspheres.With the increase of Co doping,the grain size decreases and the micro strain increases.Meanwhile,the expansion vibration of Mn-O group is enhanced.The band width of the sample is reduced,and the PL spectrum indicates that the photoelectric compound rate is reduced.Co doping enhanced its electrochemical properties,including Zn_0.7Co_0.3Mn₂O₄.It has a maximum capacitance of 296 F/g,and the long-term energy storage efficiency can reach 98.2%.