Effect Of Nickel Anode And CTAB On Hydrothermal Electrodeposition Of Mn 3 O 4 Supercapacitor Electrode Materials

As a new type of energy storage devices,supercapacitors have attracted much attention from world-wide researchers because of their high power density,long cycle life and fast charging and discharging capacity.The key to the performance and cost of the supercapacitor is the performance of the electrode,so the research on it mainly focuses on the research of the electrode.Manganese oxide is considered to be the most promising substitute of RuO₂ as a widely used capacitor electrode material due to its low cost,green and theoretical high specific capacitance?up to 1100 1300F/g?.Researchers have done a lot of research on MnO₂ and achieved a lot of results,but the study on Mn₃O₄ is much less.Therefore,this paper will be concentrated on the Mn₃O₄ as a supercapacitor electrode material research.We combined the advantages of hydrothermal and electrochemical deposition method,using hydrothermal electrochemical method on synthesis of Mn₃O₄ films.The use of three-dimensional mesh porous foam nickel as a collective,avoiding the problems of little deposition or deposition easy to fall off when deposition on nickel or titanium film.On this basis,this paper proposed the use of hydrothermal electrodeposition method to prepare the electrode material with large capacitance and high cycle life,and assembled it into an asymmetric supercapacitor to light the emitting diode.In the paper,Mn₃O₄ thin film was deposited with nickel foam and graphite anodes respectively by hydrothermal electrodeposition.X-ray diffraction?XRD?,scanning electron microscopy?SEM?,X-ray photoelectron spectroscopy?XPS?,transmission electron microscopy?TEM?,specific surface area and pore size?BET and BJH?were used to analyze the morphological characteristics and specific surface area and pore size.Electrochemical workstation was used to analyze its electrochemical properties.The morphology of the Mn₃O₄ film deposited on the nickel foam was modified by the addition of CTAB,and the capacitance performance was improved.The above-mentioned consistent structural characterization and electrochemical test were used.Finally,Mn₃O₄ deposited on the nickel foam and it deposited on the nickel foam in the presence of CTAB additives were selected as positive electrode respectively,activated carbon as the negative electrode,they were assembled into an asymmetric capacitor and its electrochemical performance and cycle stability were studied.The main findings are as follows:?1?The deposited films were made of Mn₃O₄ with nickel foam and graphite as anode respectively.When nickel foam was used as anode,Ni enters Mn₃O₄ lattice so that Ni-doped Mn₃O₄ has higher specific capacitance?434.4 mF/cm2,219.6 F/g when current density is 2 mA/cm2?,and higher cycle stability?after 19000 cycles,the capacitance retention rate was 96%?.?2?On the basis of foam nickel as the anode,the morphology of Mn₃O₄ prepared by using CTAB as the additive was changed to sheet-like,which greatly increased the specific surface area?it is increased to 141.21 m2/g,81.5% higher than that without additive?.The films prepared by using CTAB has a larger specific capacitance?476 mF/cm2,508F/g when current density is 2mA/cm2?,and a better cycle stability?after 24550 cycles,the capacitance retention rate was 96%?.?3?Using the Mn₃O₄ thin film prepared by nickel anode and CTAB additive as the positive electrode respectively,activated carbon as the negative electrode,the asymmetric supercapacitor was assembled to light the emitting diode.The capacitor with CTAB additive has a larger capacitance?147.89 mF/cm2,74.38 F/g when current density is 2 mA/cm2?,higher energy density?33.48 Wh/Kg?,larger power density?9.058 KW/kg?,and a better cycle stability?after 19100 cycles,the capacitance retention rate was 77%?.