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    不同软化点沥青对天然石墨包覆性能影响

    Influence of Pitches with Different Softening Points on the Coating Properties of Natural Graphite

    • 摘要: 选取3款不同软化点的石油基沥青,以液相包覆法处理天然石墨,对所得样品的粒度、结构、形貌和电化学性能等进行分析。结果表明,软化点为250 ℃的沥青包覆天然石墨样品表现出最佳的电化学性能,其首次库仑效率由84.70%提高到88.04%,250次循环的容量保持率由63.14%提高到81.19%。低软化点沥青由于炭化时轻组分的释放,包覆层形成大量微孔,导致不可逆容量损失较多;高软化点沥青有利于形成完整包覆层,其对天然石墨的循环性能和倍率性能改善最佳。

       

      Abstract: Three petroleum-based pitches with different softening points were used to treat natural graphite by liquid phase coating method. The particle size, structure, morphology and electrochemical properties of the samples were analyzed. The results showed that the high softening point pitch could form a thicker coating layer on the natural graphite surface, and the graphite surface became more rounded and the defects were reduced. The pitch coated natural graphite with softening point 250 ℃ showed the best electrochemical performance, the first Coulomb efficiency increased from 84.70% to 88.04%, and the capacity retention rate increased from 63.14% to 81.19% after 250 cycles. The low softening point pitch had a large irreversible capacity loss due to the large number of micropores formed by the light component releasing during carbonization, while the high softening point pitch was beneficial to the formation of complete coating, which could improve the cyclic property and rate property of natural graphite best.

       

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