Preparation And Performance Of Nickel-cobalt-manganese Oxide Composite Structure Electrode Material

Supercapacitors have become one of the mainstream energy storage devices due to their high power density,fast charging and discharging speed and good cycling performance.Electrode is an important part of supercapacitors and its structure and performance optimization have become the focus of research at home and abroad.Among them,the transition metal oxides and composite oxides have the advantages of large specific capacity and environmental friendliness,and are one of the supercapacitor electrode materials with great application potential.In this paper,three transition metal oxides and composite oxides of nickel,cobalt and manganese were taken as the research object,and the electrode materials with three different composition structures of nickel oxide,nickel-cobalt-manganese composite oxides and nickel oxide/nickel-cobalt-manganese composite oxides were prepared on the surface of the nickel foam substrate by the combined process of "chemical bath deposition-precursor calcine".The electrochemical properties,such as cyclic volt-ampere curve,constant-current charge-discharge curve and alternating impedance spectrum,as well as the physical properties,such as surface morphology and phase composition were tested.Through research,obtains the following main conclusions:(1)The effects of nickel sulfate concentration,potassium persulfate concentration,p H value,water bath temperature,reaction time and calcining temperature,heating rate and holding time of precursor in chemical bath deposition on the physical and electrochemical properties of foamed nickel/nickel oxide electrode materials were studied.Precursors during calcining temperature of 328.4 ? nickel oxide formation rate,the fastest when raising the calcining temperature to 350 ? precursor completely break down to form nanoflake structure.The specific capacity of nickel foam/nickel oxide electrode material at 2 mol/L KOH electrolyte and 1 A/g current density was 725.33 F/g,and the capacitance retention rate was 87.22% after 3000 cycles of charging and discharging at 5 A/g current density.(2)The effects of the concentration of nickel sulfate,cobalt sulfate,manganese sulfate,potassium persulfate and the calcination temperature,heating rate and holding time of the precursor on the physical and electrochemical properties of the foamed nickel/nickel-cobalt-manganese composite oxide electrode materials were studied.Calcination temperature 282.7 ? and 353.6 ?,respectively,the cobalt oxide and nickel oxide generated rate was the fastest.The specific capacity of foam nickel/nickel-cobalt-manganese composite oxide electrode material at 2 mol/L KOH electrolyte and 1 A/g current density was 1298.33 F /g,and its capacitance retention rate was 89.79% after 3000 cycles of charging and discharging at 5 A/g current density.(3)Nickel oxide/nickel-cobalt-manganese composite oxides were prepared by two-step chemical bath deposition on the surface of foamed nickel matrix.The surface of foamed nickel/nickel oxide/nickel-cobalt-manganese oxide composite electrode material presents a nanoflake composite structure with a large specific surface area.The specific capacity of the composite electrode material was increased to 1705.83 F/g at 2 mol/L KOH electrolyte and 1 A/g current density.Under the current density of 5 A/g in 1550 ~ 1950 times circulation,the capacitor to keep at a rate of 122.85%,and after 3000 cycles of charge and discharge,its capacitance retention rate still reached 103.94%.