Preparation And Application Of Manganese Dioxide-based Nanomaterials Supercapacitors

With the continuous reduction of fossil energy,the continuous increase in energy demand has led to an urgent demand for renewable resources.Among them,supercapacitor has attracted widespread attention on all walks of life because its excellent performance.Among electrode materials used in supercapacitors,transition metal oxides are widely used due to their low price,high theoretical capacitance,and good cycle stability,and MnO₂ is one of the typical representative materials.However,the conductivity of manganese dioxide is poor,which makes it difficult to interact with the electrolyte during reaction,resulting a small capacity.First,in order to increase the specific capacity of the electrode materials,the hydrothermal conditions were changed to prepare different materials.Then,SnO₂was further compound with MnO₂ electrode material to prepare binary composite materials.The main work are as follows:(1)Firstly,MnO₂ electrode material directly on 304 ultra-thin stainless steel by polymer-assisted deposition and hydrothermal,and with the help of X-ray diffractometer and other equipment to characterize the various structural properties of MnO₂ materials.Then the specific capacitance of the MnO₂ electrode material was tested for the Italian Materials Mates 510 electrochemical workstation by using cycle voltammetry and other different test methods.The results show:MnO₂ electrode material has a high specific capacitance at different hydrothermal conditions,but the specific capacitance is the highest under the condition of 160??24 h,which can be reached 1069.2 m F/cm² at 0.5 m A/cm².Moreover,the experimental results prove that the electrode material is extremely outstanding in terms of rate performance and capacitance value.(2)Afterwards,SnO₂/MnO₂ composite materials were further synthesized on the basis of the MnO₂ materials.SnO₂/MnO₂ electrode materials were prepared directly on 304 ultra-thin stainless steel by polymer-assisted deposition and electrochemical deposition.Then the elemental composition and structure morphology of MnO₂,SnO₂and SnO₂/MnO₂ nanomaterials were used XRD,XPS,SEM and TEM.In addition,the capacitance performance of the three electrode materials were tested and compared.The results show:the specific capacitance of the SnO₂/MnO₂ binary composite electrode material was significantly improved than MnO₂ and SnO₂ materials.For example,at the current density of 1 A/g,the specific capacitance of the three electrode materials of SnO₂,MnO₂,and SnO₂/MnO₂ is 161,51,and 876 F/g,respectively.In comparison,the SnO₂/MnO₂ electrode material has the best capacitance value and rate performance.(3)In order to investigate the application performance of two different electrode materials of MnO₂ and SnO₂/MnO₂ composite material,the performance of the asymmetric button supercapacitors was prepared by the two electrode materials were tested.