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Zhaolin Li, Yaozong Yang, Jie Wang, Zhao Yang, and Hailei Zhao, Sandwich-like structure C/SiOx@graphene anode material with high electrochemical performance for lithium ion batteries, Int. J. Miner. Metall. Mater., 29(2022), No. 11, pp.1947-1953. https://dx.doi.org/10.1007/s12613-022-2526-0
Zhaolin Li, Yaozong Yang, Jie Wang, Zhao Yang, and Hailei Zhao, Sandwich-like structure C/SiOx@graphene anode material with high electrochemical performance for lithium ion batteries, Int. J. Miner. Metall. Mater., 29(2022), No. 11, pp.1947-1953. https://dx.doi.org/10.1007/s12613-022-2526-0
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三明治结构高性能锂离子电池碳/氧化亚硅@石墨烯负极材料

摘要: 氧化亚硅因其高理论比容量和丰富自然资源被认为是下一代高比能量锂离子电池负极材料之一。然而,氧化亚硅在充放电过程中由于较大体积变化引起电极结构不稳定,造成性能的衰减。本研究提出一种碳包覆层–氧化亚硅–石墨烯的三明治结构,有效提高氧化亚硅负极材料在充放电过程的结构稳定性。石墨烯和碳包覆层构建出一个围绕氧化亚硅颗粒的三维电子传输网络,不仅提高材料的电极反应动力学过程,而且能均化材料表面的局部电流和电极反应程度,实现材料体积的均匀变化。此外,存在于氧化亚硅和石墨烯之间的硅–氧–碳键可以增强颗粒在石墨烯片层上的附着强度,防止氧化亚硅在嵌脱锂过程中从石墨烯上脱落。得益于上述结构优势的协同作用,碳/氧化亚硅@石墨烯材料表现出优异的循环稳定性,在0.1 C倍率下循环100圈后比容量为890 mAh/g,容量保持率为73.7%。另外,材料经历前35圈电流密度从0.1 C到5 C的逐步上升的充放电循环后恢复到0.1 C的低电流后,仍表现出886 mAh/g的可逆比容量,对应容量恢复率93.7%,表明材料的倍率性能优异。该研究提供一种提高高容量型锂/钠离子电池负极材料结构稳定性的新策略。

 

Sandwich-like structure C/SiOx@graphene anode material with high electrochemical performance for lithium ion batteries

Abstract: Silicon suboxide (SiOx, 0 < x < 2) is recognized as one of the next-generation anode materials for high-energy-density lithium ion batteries (LIBs) due to its high theoretical specific capacity and abundant resource. However, the severe mechanical instability arising from large volume variation upon charge/discharge cycles frustrates its electrochemical performance. Here we propose a well-designed sandwich-like structure with sandwiched SiOx nanoparticles between graphene sheets and amorphous carbon-coating layer so as to improve the structural stability of SiOx anode materials during cycling. Graphene sheets and carbon layer together construct a three-dimensional conductive network around SiOx particles, which not only improves the electrode reactions kinetics, but also homogenizes local current density and thus volume variation on SiOx surface. Moreover, Si–O–C bonds between SiOx and graphene endow the strong particle adhesion on graphene sheets, which prevents SiOx peeling from graphene sheets. Owing to the synergetic effects of the structural advantages, the C/SiOx@graphene material exhibits an excellent cyclic performance such as 890 mAh/g at 0.1 C rate and 73.7% capacity retention after 100 cycles. In addition, it also delivers superior rate capability with a capacity recovery of 886 mAh/g (93.7% recovery rate) after 35 cycles of ascending steps at current range of 0.1–5 C and finally back to 0.1 C. This study provides a novel strategy to improve the structural stability of high-capacity anode materials for lithium/sodium ion batteries.

 

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