Study On Nanometer Carbon - Based Transition Metal Oxide For High - Power Lithium - Ion Negative Electrode

Graphene nanosheets are regarded as potential electrodes in Li-ion batteries（LIBs）, therefore, it is of great essentially to synthesis these materials with both low-cost and productivity. Transition metal oxides have higher theoretical specific capacity compared with pure carbon material. While using as the negative electrode material, there are many drawbacks, such as: poor electrical conductivity, undesirable stability, the huge volume change during the lithiation/delithiation process. Recently, the flexible electrodes（such as carbon cloth, carbon paper and foam nickel） gradually replace the traditional electrodes（coated on copper foil）. 3-D flexible substrate can be co-precipitated into three-dimensional structure with special morphology by the hydrothermal or solvent thermal process and the heat treatment process.Porous graphene-like nanosheets（PGS） have been synthesized from expandable graphite（EG） by firstly intercalating phosphoric acid, followed by an annealed process to enlarge the interlayer distance of EG, which is favorable for subsequent intercalation of zinc chloride. Then, the followed pyrolysis of zinc chloride in the interlayer of EG could form the porous structure with the gas produced. This material can be used for electronics, sensors and energy storage and conversion.This paper combines graphene with cobalt oxide and sulfide. Graphene nanosheets have layer structure, in favor of the electrons and ions into the surface and promote the reaction quickly. More importantly, the nanosheet of graphite layers and the transition metal oxide have more active sites and the contact area, increasing the conductivity of the material, which reduces the volume expansion during charge and discharge process, Hence, improving the charge/discharge capacity, rate characteristics and cycle stability.This paper has synthesis murdochite-type Ni6MnO8 and spinel MnCo₂O₄ growing- IIIon carbon cloth by using this method. As a self-supporting electrode, without adding any adhesive in the reaction process, which can be used directly in the lithium-ion battery anode material, improving electrical conductivity and cycling stability of the material. Moreover, binary metal oxides have higher theoretical specific capacity than single-metal oxides. There are more contact areas and active sites between the carbon cloth and binary metal oxides, which not only improve its capacity and rate performance, but also can buffer the large volume expansion/shrinkage during the lithium insertion/extraction cycles.