Study On Supercapacitive Property Of MoO₂ Nanocomposites With Different Structure

Supercapacitors have been widely used in the field of energy storage due to their advantages,such as high power density and long-term cycling stability.As the core of the supercapacitors,the electrode material inside has always been the focus of scientists'attention.So far,a variety of materials,including carbon and metal oxides,have been developed and used for supercapacitors studies.In recent years,molybdenum dioxide?MoO₂?and its composites have received much attention from researchers in supercapacitors due to its low cost,environmental friendliness and high electrochemical activity.However,when used as electrode materials,the application of MoO₂ as supercapacitors is limited due to its poor conductivity and inefficient use of its active surface.In this thesis,several kinds of MoO₂ composites were prepared through making nano-scale MoO₂ compositing with carbon material and used for supercapacitors performance studies.The specific studies are as follows:?1?Study on the performance of carbon-coated MoO₂ nanosphere/graphene composite as supercapacitors electrode.The surface of MoO₂@C nanosphere was similar to ball of wool which can provide more active surfaces in contact with electrolyte.The modification of surface potential solved the problem that graphene was difficult to compound with other materials.And the introduction of graphene sheets improved the charge transfer efficiency while improving the structural stability.When used as electrode of supercapacitors,the carbon-coated MoO₂ nanosphere/graphene composite exhibited a high specific capacitance of 509.8 F g^-1 at 1 A g^-1;?2?Study on the performance of carbon-coated MoO₂ nanoparticles anchored on graphene composite as supercapacitors electrode.The nanometerization of MoO₂increased the active surface,and the introduction of graphene improved the charge transfer efficiency while alleviating the agglomeration of MoO₂ nanoparticles.When used as electrode of supercapacitors,the carbon-coated MoO₂ nanoparticles anchored on graphene composite delivered remarkable electrochemical performance with a high capacitance(1224.5 F g^-1 at 1 A g^-1);?3?Study on the performance of budding-branch like carbon-coated MoO₂/carbon nanotube composite as supercapacitors electrode.When used as electrode of supercapacitors,the budding-branch like carbon-coated MoO₂/carbon nanotube composite exhibited a superior specific capacitance of 1667.2 F g^-1 at 1 A g^-1 due to its open and stable structure and the introduction of carbon nanotube.