Preparation And Properties Of Graphene Molybdenum And Nickel Oxide Composites

The continuous innovation and progress of science and technology not only promotes the continuous development of the design and development of high-performance energy storage devices,but also puts forward more stringent requirements for new energy storage devices.Supercapacitors have high power density,superlong lifespan,fast charge and discharge rates,environmental friendliness and excellent reliability,rendering them a highly promising candidate for next-gen eration high-efficient energy storage devices.Among them,the electrode material is the research center to improve the performance of any SCs.Under this background,this work takes molybdenum as the core element,ultralong molybdenum oxide nanorods,highly active nickel molybdate and molybdenum oxide/nickel molybdate(MoO3/NiMoO4)core-shell electrode materials were constructed by hydrothermal,calcination and ultrasonic methods,and composite electrodes were obtained by combining these materials with graphene.The research contents of this project are as follows:(1)Ultra-long ?-MoO3 porous nanorods were synthesized by a simple one-step hydrothermal method by adjusting pH value with nitric acid.Porous and large specific surface area can not only greatly improve the conductivity of molybdenum trioxide,but also significantly improve the electrochemical activity,and promote faster charge storage kinetics,and at the same time,in order to further promote electron transfer and ion transport.Graphene molybdenum trioxide nanocomposites with threedimensional sandwich structure were prepared by ultrasonic method,which showed excellent electrochemical performance.The composite material has excellent specific capacity(370F g-1)and cycle retention rate,capacitance retention rate after 10000 charge and discharge at 20A g-1 is 63.7%.(2)NiMoO4 nanorods with high activity were prepared by the combination of simple,rapid and environmentally friendly one-step hydrothermal method and calcination method.GO@NiMoO4 composites have high performance as electrode materials for supercapacitors.When the current density is 1A g-1,the specific capacitance reaches 721Fg-1,which is much higher than that of pure NiMoO4(405F g-1),and almost three times that of the original ?-MoO3 electrode(214F g-1).(3)NiMoO4 modified ?-MoO3 nanorods were synthesized by a simple two-step hydrothermal method.Molybdenum trioxide nanopores are completely covered by ultra-thin mesoporous NiMoO4 layer,that is,MoO3/NiMoO4 core/shell nanopores.Due to the high electrochemical activity of NiMoO4,the surface recombination effect of NiMoO4 and MoO3,the porous structure of NiMoO4 shell and abundant active sites,molybdenum trioxide is used as an "ion buffer reservoir".The MoO3/NiMoO4 electrode has a high specific capacity of 819F g-1 and has good rate capacity and excellent cycle performance in 3M KOH electrolyte.In addition,the specific capacity of the GO@MoO3/NiMoO4 composite electrode prepared by the composite of MoO3/NiMoO4 and graphene was as high as 1031F g-1,and the capacity retention reached 74.8%after 10000 cycles.Figure[33]Table[6]References[119]...