Application Of The Three-dimensional Structure Of Graphene-based Clad Hollow Fe₂O₃ Composite Material In Electrochemistry

Because graphene has many excellent properties, such as the advantages of mechanical strength, good electrical conductivity and having a large specific surface area, etc. to promote their material in storage, electric vehicles and the wearable device and go more application development, but also promote this composite graphene-based nanomaterials provide a broader opportunity in the new energy. And graphene-based composite hollow structure is formed larger than the surface area, can accelerate the transport of charge transfer, and reduction of graphene oxide as a carrier, coating and other active organic materials inorganic materials, help to build a more graphene group a hollow structure. These excellent redox graphene materials are often used for supercapacitors, lithium-ion batteries and anther energy storage devices and wearable material.Whether it is in the super-capacitor, or a lithium ion battery, ferric oxide more and more attention this because of its environmentally friendly, high theoretical capacity. However, in electrochemistry, conductivity, volume effect ferric oxide expansion, greatly limiting its development as an electrode material. However, due to this excellent properties of the graphene. the graphene-coated ferric oxide, to prepare a large surface area, to improve the conductivity and volume effect, which increases the electrochemical properties of the composite material.In this paper, the synthesis of self-assembled three-dimensional graphene-based clad hollow structural ferric oxide nanocomposites because of its crystal form conversion, hollow structural framework remains unchanged, and is mainly used in lithium-ion battery and supercapacitor two aspects:（1） Graphene basal group, hydrothermal method to prepare a three-dimensional graphene-coated hollow structured titanium iron oxide composite material （SHFS）, in a nitrogen environment,500 degrees annealing 2 hours to obtain y-Fe2O3 being restored coated with graphene oxide, SHFS-500 has been found to 198m2 g^-1 having a high specific surface area, and good supercapacitor electrode material, the current density of 2 A g^-1 condition, the capacitance ratio reaches 332.7 F g^-1 of ultra-high capacitance, cyclic ring 1000, the efficiency ratio is basically stable, at 10 A g^-1 in while still maintaining 98 F g^-1, so this excellent performance may be due to the hollow structured of the y-Fe2O3 in optimal structure as graphene sheets have results next calcined at 500℃ functioning.（2） We will SHFS-500 for example lithium battery test, as an electrode material,100 mA g- 1, after 50 cycles, the lithium-ion battery performance 950 mAh g^-1, and a high current density at 1000 mA h^-1 capacity is still to 640 mAh g^-1. The lithium-ion batteries to improve the performance of composites.