以 Fe3C 或 Mn 取代物 (Fe3C/Fe3O4) 作为锂电池负极的碳纳米复合材料的结构和电化学性能研究,Applied Surface Science

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以 Fe3C 或 Mn 取代物 (Fe3C/Fe3O4) 作为锂电池负极的碳纳米复合材料的结构和电化学性能研究
Applied Surface Science ( IF 6.3 ) Pub Date : 2020-12-01 , DOI: 10.1016/j.apsusc.2020.147474
A. Gangwar , A. Sharma , S.K. Shaw , Sher Singh Meena , N.K. Prasad

摘要 Fe3O4 或Fe3C 或Fe3O4/Fe3C 与碳的纳米复合材料由于其较高的理论容量而被用作锂离子电池的负极材料。目前的工作描述了碳与 Fe3C 或 MnrFe3-rC/MnsFe3-sO4（其中 0.2 ≤ r + s ≥ 0.7）的纳米复合材料（~5-25 nm）的充电容量。这些复合材料是使用廉价的尿素辅助溶胶-凝胶途径合成的，然后在惰性气氛中在 700°C 下进行热处理。X 射线和电子衍射证实样品中存在 Fe3C、Fe3O4 和碳相。X 射线光电子能谱描绘了纳米复合材料 M7FOC 元素的氧化态。穆斯堡尔光谱进一步支持了早期研究的结果。材料的电极动力学和电化学性能通过伏安图和恒电流锂化/脱锂图进行评估。还评估了与室温下循环次数相关的比电荷容量和库仑效率。观察到 M7FOC 样品的最佳比容量约为 1261 mAh g-1，而在初始循环后以 C/20 的速率发现其可逆比锂化容量约为 841 mAh g-1。

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Structural and electrochemical performance studies for nanocomposites of carbon with Fe3C or Mn-Substituted (Fe3C/Fe3O4) as anodes for Li-batteries

Abstract The nanocomposites of Fe3O4 or Fe3C or Fe3O4/Fe3C with carbon are exploited as anode materials for Li-ion batteries due to their higher theoretical capacities. The present work depicts the charging capacity of nanocomposites (~5–25 nm) of carbon with Fe3C or MnrFe3-rC/MnsFe3-sO4 (where 0.2 ≤ r + s ≥ 0.7). These composites are synthesized using an inexpensive urea assisted sol–gel route which are then heat treated at 700 °C in an inert atmosphere. The x-ray and electron diffractions validate the presence of Fe3C, Fe3O4, and carbon phases in the samples. The X-ray photoelectron spectroscopy depicts the oxidation states for the elements of nanocomposite M7FOC. Mossbauer spectroscopy further supports the findings of earlier studies. The electrode kinetics and the electrochemical performance for the materials are assessed by Voltammograms and Galvanostatic lithiation/delithiation plots. The specific charge capacities and Coulombic efficiencies with respect to cycle numbers at room temperature are also evaluated. The optimum specific capacity of ~1261 mAh g−1 is observed for M7FOC sample whereas its reversible specific lithiation capacity is found to be around 841 mAh g−1 after the initial cycle at the rate of C/20.

更新日期：2020-12-01

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