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研究了氧化微扩层处理对天然鳞片石墨晶体结构、表面形貌及其电化学性能的影响。结果表明,经氧化微扩层处理后,鳞片石墨的平均层间距d002略微增大,平均晶粒尺寸显著减小,鳞片石墨颗粒表面出现刻蚀和片层剥落现象。氧化微扩层处理1 h后,鳞片石墨的首次可逆容量从331.9 m A·h/g提高至364.7 m A·h/g,首次库伦效率从86.5%提高至88.8%。经过氧化微扩层处理,石墨的平均晶粒尺寸减小,锂离子在碳层表面及边缘嵌入量增加;在石墨表面引入的纳米级孔隙结构进一步增大了锂离子存储空间;同时,对表面细小颗粒的刻蚀清除,使石墨比表面积减小,是可逆容量和首次库伦效率提高的主要原因。
The effects of oxidized micro-dilation on the crystal structure, surface morphology and electrochemical properties of natural flake graphite were investigated. The results showed that the average interlayer spacing d002 of flake graphite slightly increased, the average grain size decreased remarkably and the surface of flake graphite particles appeared etching and flaking after oxidized micro-dilation treatment. The first reversible capacity of flake graphite increased from 331.9 m A · h / g to 364.7 m A · h / g after 1 h of oxidative micro-dilation. The first coulombic efficiency increased from 86.5% to 88.8%. After oxidized micro-dilation process, the average grain size of graphite decreases, and the amount of lithium ions embedded in the surface and edge of the carbon layer increases; the nano-scale pore structure introduced on the graphite surface further increases the storage space of lithium ions; meanwhile, Etching of small particles to remove graphite to reduce the specific surface area is the main reason for the reversible capacity and the first increase in the efficiency of Coulomb.