Research On High-rate Lithium-ion Battery Silicon Monoxide/Graphene Anode Materials

Graphene has a high electrical conductivity, high specific surface area, the sheetelastic structure and high chemical stability, suitable as anode materials of lithium ionbatteries. Silicon-based materials have a high theoretical capacity.In this research, chemical reduction and thermal reduction were used to preparegraphene, high-temperature expansion prepared graphene compared to graphitepowder and micron graphite as raw material graphene morphology; using high-speedgrinding machine to process industrial silicon monoxide particles to obtain SiOnanoparticles; SiO/graphene material was prepared by two methods. X-ray diffraction（XRD）, scanning electron microscopy （SEM）, transmission electron microscopy（TEM）, thermal gravimetric analysis （TGA） and other methods were used forcharacterization, charge-discharge test examines the material properties and cycleperformance magnification, cyclic voltammetry （CV） and electrochemical impedancespectroscopy （EIS） produce analysis of the electrochemical properties of the material.In this research it was found that comparing nano-layer graphene obtained afterhigh-temperature thermal expansion, graphene obtained after chemical-thermalreduction by reducing the surface is smooth and flat; in microns graphite as rawmaterial graphene sheet aggregates into the presence of graphene nest phenomenon.Reduced graphene was under100mA g^-1cycle50cycles, the charge was486mAh g^-1and480mAh g^-1, the capacity retention rate of44%for the first time, Coulombefficiency of98.77%.In the high-speed grinder speed2000rpm SiO particles to one the grinding2h,silicon monoxide44um particle size is reduced to the initial50-300nm, the specificsurface area increases from the initial3.8m²g^-1up to28.2m²g^-1.Prepared by mechanical mixing SiO/graphene nano-layer mixture （SiO/GN） and insitu chemical-thermal reduction composite prepared by SiO/reduced graphenecomposites （SiO/RG）, charge-discharge performance test show100mA g^-1in the nextcycle100cycles, SiO/RG discharge electrode890and the charge capacity was883mAh g^-1; coulombic efficiency was99.2%, and SiO/GN672and661.2mAh g^-1,coulombic efficiency to98.39%. SiO/RG electrode at a current density of200,400,800and100mA g^-1cycles, the average capacity was890,701,441and933mAh g^-1.