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通过化学气相沉积的方法,以乙炔为碳源,天然石墨球为原料,采用不同流化床CVD工艺和不同的反应时间,制备出具有光滑表面或颗粒状热解炭包覆层的核-壳构型改性天然石墨球。改性天然石墨球的核体是具有高度有序石墨结构的天然石墨,而壳体是无序结构的热解炭。与天然石墨球相比,具有核-壳结构的改性天然石墨球的首次库仑效率和循环性能都得到显著改善。尤其是具有颗粒状热解炭包覆层的改性石墨具有优异的循环性能,在41次循环后其放电容量仍为首次容量的84%,这一改善归因于表面沉积的颗粒状热解炭有效地降低了改性天然石墨颗粒之间的接触电阻和增加了接触面积。
By chemical vapor deposition, acetylene as a carbon source, natural graphite balls as raw materials, using different fluidized bed CVD process and different reaction time, prepared with a smooth surface or granular pyrolytic carbon cladding core - shell Configuration modified natural graphite ball. The nuclei of modified natural graphite balls are natural graphite with a highly ordered graphite structure, whereas the shells are pyrolytic carbon with a disordered structure. The first coulombic efficiency and cycle performance of modified natural graphite spheres with core-shell structure are significantly improved compared to natural graphite spheres. In particular, the modified graphite with granular pyrolytic carbon coating has excellent cycling performance, and its discharge capacity is still 84% of the initial capacity after 41 cycles, which improvement is attributed to the granular pyrolysis of surface deposition Carbon effectively reduces the contact resistance between modified natural graphite particles and increases the contact area.