Study On Composite Electrode Materials Of Sulfur Modified Graphene And Manganese Oxide

Supercapacitor is a new energy storage device between battery and capacitor.It has high energy density and power density,and maintains good cycle performance.It can be said to be a bridge connecting traditional battery and capacitor.In order to further improve its specific capacity,S-modified graphene and manganese tetroxide composites and graphene and nano-flower manganese dioxide composites were prepared by one-step in-situ growth on graphene oxide substrates,and their properties as electrode materials for supercapacitors were investigated.The main contents of this paper are as follows:(1)S-Mn304/graphene composites were prepared by one-step hydrothermal in-situ growth using thiourea and potassium permanganate as sulfur and manganese sources respectively.Among them,Mn304 crystals prepared by the reaction of thiourea and potassium permanganate are uniformly dispersed on the surface of graphene.At the same time,when graphene oxide is reduced by thiourea,sulfur-containing functional groups are successfully grafted onto the carbon atoms of graphene.The growth conditions of manganese tetroxide in the synthesis process were discussed.The electrochemical test of the new composite material was carried out and the results were analyzed.When the current density was 4A/g,the maximum specific capacity was 128F/g,and the original specific capacity remained 98%after 2000 cycles.(2)Graphene/nano-flower manganese dioxide composite electrode material was prepared by one-step hydrothermal method using potassium permanganate as manganese source.In the constant current charge-discharge test of 0.5A/g,it has the maximum specific capacity of 140 F/g.The electrochemical performances of the composite electrode materials with different doping amount of manganese dioxide were compared.It was found that the capacitance performance of the composite electrode materials was better when the doping amount was 5%.