Preparation And Properties Of Nano Structured Manganese Silicate As Electrode Material

Supercapacitor is a new type of energy storage device,which has the advantages of fast charging and discharging rate,high power density and small environmental pollution.Supercapacitors have attracted widespread attention from researchers.Exploration of novel structural metal silicates as electrode candidates is an efficient strategy to develop low-cost electrode for supercapacitors.Therefore,this paper takes manganese silicate as electrode material for supercapacitor.The phase and morphology of electrode material were characterized by XRD,SEM,TEM and N₂adsorption-desorption experiments.The electrochemical properties of electrode material were analyzed by CV,GCD,EIS and cycle life test.These research contents of this paper are summarized as follows:1.Mesoporous structure manganese silicate as electrode materialMesoporous manganese silicate was synthesized by controlling the hydrothermal temperature with mesoporous SBA-15 as self-reactive template and manganese acetate as manganese source.The mesoporous manganese silicates exhibited uniform pore-size distribution of 3-6 nm and high specific surface area ranging from 244.2 to374.7 m²/g.A series of electrochemical analysis demonstrated that the electrode for sample obtained at 160^oC showed the excellent electrochemical performance.A high specific capacitance of 251 F/g at 0.5 A/g in 6 M KOH electrolyte and good rate performance were achieved,which was mainly attributed to its high crystallinity and large specific surface areas facilitating electrochemical process.2.Core-shell structure manganese silicate with different particle sizes as electrode materialCore-shell structure manganese silicate was designed and fabricated through a facile hydrothermal route with silica sphere of different particle sizes as template and silicon source.The core-shell spheres with controllable particle size dispaly high crystallinity and monodispersity.A series of electrochemical analysis demonstrate that the SiO₂@manganese silicate core-shell sphere prepared using small silica sphere with the diameter of 160 nm possesses desirable electrochemical properties.A specific capacitance of 297.33 F/g at a current density of 0.5 A/g and good rate performance are achieved.The excellent surface-dependent electrochemical performance of manganese silicate is associated with its distinctive core-shell structure and large surface area,which effectively shorten the transport path of the ion/electron and also provide more electroactive sites.3.Core-shell structure manganese silicate with different shell thickness as electrode materialManganese silicate core-shell sphere with different shell thickness was prepared by sacrificial assisted template-hydrothermal method using silica sphere with certain particle size as both template and silicon source and adding different concentrations of manganese acetate.The core-shell spheres with controllable shell thickness dispaly high crystallinity and monodispersity.All the samples are composed of a large number of nanoparticles corresponding to crystalline manganese silicate,and the surface is rough and porous.The samples present a core-shell structure with silica spheres as the core and manganese silicate as the shell.A series of electrochemical analysis show that the thicker shell SiO₂@manganese silicate core-shell sphere has better electrochemical performance.This electrode has a specific capacitance of207.1 F/g at a current density of 0.5 A/g,which has good rate performance and lowest charge transfer resistance.These results of the study show that manganese silicate is a controllable,easy to prepare,low cost and promising electrode material.It has a wide application value in supercapacitor.