Synthesis And Supercapacitive Performance Of Binary Transition Metal Derivative And Graphene Composites

With the rapid development of society,the portable electronic products which has been used on power source is becoming wide popular.While the present energy storage element always suffer from long charge and discharge time,low power density and poor cycling stability,which can't meet the demands of practical application.And it is of great significance to develop a new generation of energy storage elements with shortercharge and discharge time,higher power density and better cycling stability.The supercapacitor,as a new kind of energy storage element with wide development prospect,has the features of high power density,high ratecapacity and long circling life.For the supercapacitor,its performance mainly depends on the performance of electrode materials,the better electrochemistry property the electrode material has,the better performance the supercapacitor obtains.However,single materials could not meet the requirements of practical application due to the intrinsic defects,while the composites,depending onthe synergic effect in chemical reactions,have a distinct advantage in improving the properties of electrode material.To improve the properties of electrode material implied in supercapacitor,this research synthesizes a composite based on binary transition metal derivatives and carbon-based material graphene and studies its property.The following main topics are included in this dissertation:A composite(ZnFe2O4/NRG)with a unique structure based on ZnFe2O4 nanoparticles and nitrogen-doped grapheme is synthesized through hydrothermal and calcined method.Firstly,the growth of ZnFe2O4 crystal,the reduction of graphitic oxide and the nitrogen doping to graphene are completed through hydrothermal method.When the NRG is used as the substrate,it can not only control the formation of nano-sized ZnFe2O4,but also guarantee the high dispersion without any agglomeration.After that,the composite is decorated through calcined method.Finally,the capacitance characteristics of composite is tested,it is found that the composite has the features of good ratecapability and high cycling stability.This synthetic method provides a new way to improve the performances of electrode material.A graphene-coated Co9S8 nanoparticles composite(Co9Ss/rGO)is synthesisedby a combination of coprecipitation method,hydroxide method and calcination method.Firstly,a CoCO3/GO precursor is synthesized through coprecipitation method,and then the composite(Co9S8/rGO)is synthesized through hydroxide method and calcination method.After that,the capacitance characteristicsof the composite is tested,it is found that the composite has the features of good conductivity,high specific capacity,good ratecapability and high cycling stability.Thus,the composite has excellent capacitance characteristics,and it is an ideal material for accumulation of energy.