摘要
二氧化锡(SnO2)由于其高理论容量被视为锂离子电池石墨负极材料的优秀替代品,但其大的体积变化和较差的导电性导致容量衰减速度较快.为解决这些问题,本研究提出了一种制备氮掺杂碳涂层(HS-SnO2@NxC)包覆的空心结构二氧化锡球的方法,对其结构和元素进行分析,并对HS-SnO2@NxC作为锂离子电池负极材料的电化学性能进行了研究.研究结果表明,空心结构有助于缓解充放电过程中材料体积的变化,而氮掺杂碳涂层的存在则强化了材料的结构完整性,进而优化了电荷的传递过程.得益于这些优势,HS-SnO2@NxC电极在0.25C下经过750次循环后,仍能保持610 mA·h/g的稳定容量.同时,在5C(1C=800 mA/g)的倍率测试后,其稳定容量仍可达425 mA·h/g,容量保持率高达76.7%.这些结果表明,SnO2有望成为新一代高性能锂离子电池负极材料,为这一领域的研究提供了新视角.
Abstract
Despite the high theoretical capacity as the anode material adopted in lithium-ion batteries,SnO2 materials undergo rapid capacity fading and low-rate performance due to the significant volume change and poor conductivity.This research proposes a straightforward approach to prepare hollow structured SnO2 spheres based on the N-dopped C coating layer(HS-SnO2@NxC)to overcome these problems.The structural and elemental characterizations were performed,and the cycling performance of HS-SnO2@NxC was systematically investigated.The presence of a hollow void in the HS-SnO2@NxC material allows for adaptation to volume changes during the charging and discharging process.Additionally,the outer framework of NxC strengthens the structural integrity of the spheres and facilitates the transfer of electrons and charges.These factors significantly improve the rate performance of the anode material.Owing to these advantages,HS-SnO2@NxC electrodes delivered a stable capacity of 610 mA·h/g at 0.25C after 750 cycles.Meanwhile,the great reversible rate performance of 76.7%was attained after a superior rate performance of 425 mA·h/g at 5C(1C=800 mA/g).
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