State Key Laboratory of Powder Metallurgy, College of Chemistry and Chemical Engineering , Central South University , Changsha 410083 , Hunan , China.
College of Chemistry Chemical and Environmental Engineering , Henan University of Technology , Zhengzhou 450000 , Henan , China.
ACS Appl Mater Interfaces. 2019 Mar 20;11(11):10829-10840. doi: 10.1021/acsami.8b20477. Epub 2019 Mar 11.
As an anode for lithium-ion batteries, metallic bismuth (Bi) can provide a superb volumetric capacity of 3800 mA h cm, showing perspective value for application. It is a pity that the severe volume swelling during the lithiation process leads to the dramatic deterioration of the cycling performances. To overcome this issue, Bi nanorods encapsulated in N-doped carbon nanotubes (yolk-shell Bi@C-N) are elaborately designed through in situ thermal reduction of BiS@polypyrrole nanorods. In comparison with the commercial Bi, the lithium storage capacities of Bi@C-N are significantly enhanced, and it presents a stable volumetric capacity of 1700 mA h cm over 500 cycles at a high current density of 1.0 A g, nearly 2.2 times that of graphite. The N-doped carbon nanotube and the cavity between the carbon wall and Bi jointly contribute to this superior performance. Especially, the failure mechanism of Bi nanorods and the protective effect of the carbon shell are revealed by ex situ TEM, which illuminates the decreasing tendency in the initial 10-20 cycles and the subsequent stable trend of cyclic performance.
作为锂离子电池的阳极，金属铋（Bi）提供了卓越的 3800 mA h cm3 的体积容量，具有应用的前景价值。遗憾的是，在锂化过程中严重的体积膨胀导致循环性能的急剧恶化。为了克服这个问题，通过原位热还原 BiS@聚吡咯纳米棒，精心设计了氮掺杂碳纳米管（蛋黄壳 Bi@C-N）封装的 Bi 纳米棒。与商业 Bi 相比，Bi@C-N 的锂离子存储容量显著提高，在 1.0 A g 的高电流密度下，经过 500 次循环后，它具有稳定的体积容量 1700 mA h cm3，是石墨的近 2.2 倍。氮掺杂碳纳米管和碳壁与 Bi 之间的腔共同促成了这种卓越的性能。特别是，通过原位 TEM 揭示了 Bi 纳米棒的失效机制和碳壳的保护作用，阐明了初始 10-20 个循环的下降趋势和循环性能的后续稳定趋势。
