Rapid Preparation Of Electrode Materials For Flexible Graphene-based Supercapacitors

Supercapacitors have attracted much attention because of their excellent cyclic stability and high specific capacity.The electrode material is the decisive factor to determine the capacitance performance.If the composite electrode material is prepared by combining graphene with manganese dioxide,not only the excellent conductivity of graphene can be fully utilized,but also the pseudo-capacitance effect of manganese dioxide can be used to improve the energy density of the capacitor.The aim of this paper is to rapidly prepare graphene-manganese dioxide composite electrode materials by one-step laser sintering.Graphene oxide prepared by Hummers method this paper(GO)hydrogel as a raw material,adopting water-soluble manganese salt(anhydrous manganese sulfate and manganese acetate)as a source of manganese,in the flexible conductive substrate(titanium foil)by using the method of coating preparation of graphene oxide-Mn2+composite membrane,and then using the laser sintering,the high temperature of laser focus on to GO back to square one also graphene oxide(RGO)at the same time,the high temperature cracking into manganese dioxide and manganese salt and flexible RGO-MnO2 composite electrode is prepared The surface photoelectron spectroscopy(XPS)was used to analyze the elemental composition and valence state of the composites.The electrochemical properties of composite electrode materials were evaluated by means of constant current charge-discharge and cyclic voltammetry.The conclusions were as follows.(1)Firstly,the GO-manganese sulfate composite membrane prepared by the mold with thickness of 50 micrometers was taken as the research object,and the optimal preparation conditions of the composite electrode materials were determined by orthogonal experimental methods.The results show that under the condition of this film thickness,the optimized laser sintering power is250mW and the scanning time scale is 8,and the specific capacitance of the optimized composite electrode material is as high as 37.71mF/cm~2.(2)The thickness of the film was measured by using a film prepared by a mold having a thickness of 100?m(raw material as above)as a research condition,and the influence of the film thickness change and the laser sintering condition on the properties of the finally prepared composite electrode was investigated.The results show that when the laser power is 270mW and the scan time scale is 17,the specific capacitance of the prepared composite electrode material is the highest,reaching 31.23mF/cm~2.(3)We also studied the effect of different manganese sources on the performance of composite electrodes,using manganese acetate and graphene oxide as raw materials.The optimal preparation conditions were studied by orthogonal experiment.The final conclusions are as follows:The raw material film prepared by 50 micron mold is optimized to have a laser power of 230 mW and a scan time scale of 8.The specific capacitance of the optimized composite electrode material can reach 23.09.mF/cm~2.(4)We used SEM to analyze the changes of the microstructure of the electrode materials,and combined with XPS to analyze the valence state of Mn.The experimental results show that under the research conditions of this paper,we have prepared a composite electrode of graphene-manganese-manganese dioxide.material.