Preparation of natural microcrystalline graphite with high sphericity and narrow size distribution

Natural microcrystalline graphite with high sphericity and narrow size distribution was prepared by powder engineering methods. The shape of microcrystalline graphite (MCG) particles was modified using a wet agitating method and then the particles were separated into groups with narrow size distribution by means of gravity settling and hydrocyclone combined. Several methods such as scanning electron microscope (SEM), Raman spectroscopy and X-ray diffraction (XRD) were employed to investigate the structure of the sample. The result showed that the present method was effective in classifying the MCG particles into a narrow size range. Galvanostatic cycling was used to investigate the electrochemical performance of the as-prepared MCG as the anode material of lithium ion cells. Compared with raw MCG, the modified MCG shows a large improvement in reversible capacity, though the cycleability is slightly reduced.