Luo Dan, Zhang Zhen, Li Gaoran, Cheng Shaobo, Li Shuang, Li Jingde, Gao Rui, Li Matthew, Sy Serubbabel, Deng Ya-Ping, Jiang Yi, Zhu Yanfei, Dou Haozhen, Hu Yongfeng, Yu Aiping, Chen Zhongwei
Department of Chemical Engineering, Waterloo Institute of Nanotechnology, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada.
Department of Condensed Matter Physics and Materials Science, Brookhaven National Laboratory, Upton, New York 11973, United States.
ACS Nano. 2020 Apr 28;14(4):4849-4860. doi: 10.1021/acsnano.0c00799. Epub 2020 Mar 20.
The notorious shuttling behaviors and sluggish conversion kinetics of the intermediate lithium polysulfides (LPS) are hindering the practical application of lithium sulfur (Li-S) batteries. Herein, an ultrafine, amorphous, and oxygen-deficient niobium pentoxide nanocluster embedded in microporous carbon nanospheres (A-NbO@MCS) was developed as a multifunctional sulfur immobilizer and promoter toward superior shuttle inhibition and conversion catalyzation of LPS. The A-NbO nanocluster implanted framework uniformizes sulfur distribution, exposes vast active interfaces, and offers a reduced ion/electron transportation pathway for expedited redox reaction. Moreover, the low crystallinity feature of A-NbO manipulates the LPS chemical affinity, while the defect chemistry enhances the intrinsic conductivity and catalytic activity for rapid electrochemical conversions. Attributed to these superiorities, A-NbO@MCS delivers good Li-S battery performances, that is, high areal capacity of 6.62 mAh cm under high sulfur loading and low electrolyte/sulfur ratio, superb rate capability, and cyclability over 1200 cycles with an ultralow capacity fading rate of 0.024% per cycle. This work provides a synergistic regulation on crystallinity and oxygen deficiency toward rapid and durable sulfur electrochemistry, holding a great promise in developing practically viable Li-S batteries and enlightening material engineering in related energy storage and conversion areas.
中间产物多硫化锂（LPS）臭名昭著的穿梭行为和缓慢的转化动力学阻碍了锂硫（Li-S）电池的实际应用。在此，一种嵌入微孔碳纳米球（A-NbO@MCS）中的超细、非晶态且缺氧的五氧化二铌纳米团簇被开发为一种多功能硫固定剂和促进剂，用于高效抑制LPS的穿梭并催化其转化。植入A-NbO纳米团簇的骨架使硫分布均匀，暴露出大量活性界面，并提供了一条缩短的离子/电子传输路径，以加速氧化还原反应。此外，A-NbO的低结晶度特性调控了LPS的化学亲和力，而缺陷化学增强了本征导电性和快速电化学转化的催化活性。得益于这些优势，A-NbO@MCS展现出良好的锂硫电池性能，即在高硫负载和低电解液/硫比的情况下具有6.62 mAh cm的高面积容量、出色的倍率性能以及超过1200次循环的循环稳定性，每循环的超低容量衰减率为0.024%。这项工作提供了一种对结晶度和氧缺陷的协同调控，以实现快速且持久的硫电化学，在开发实际可行的锂硫电池以及启发相关储能和转换领域的材料工程方面具有巨大潜力。
