Liu Jianbin, Qiao Zhensong, Xie Qingshui, Peng Dong-Liang, Xie Rong-Jun
College of Materials, State Key Laboratory of Physical Chemistry of Solid Surfaces and Fujian Province Key Laboratory of Materials Genome, Xiamen University, Xiamen 361005, P. R. China.
ACS Appl Mater Interfaces. 2021 Apr 7;13(13):15226-15236. doi: 10.1021/acsami.1c00494. Epub 2021 Mar 26.
Lithium-sulfur (Li-S) batteries are regarded as one of the most promising next-generation battery technologies owing to their ultrahigh energy density up to 2600 W h kg and low cost. However, major challenges still remain in the application of Li-S batteries, such as shuttle effect and sluggish redox kinetics. Herein, it is demonstrated that phosphorus doping can not only significantly improve the polysulfide adsorption but also enhance the catalysis effects of metal-organic framework-derived CoS nanoboxes in Li-S batteries. Consequently, a modified separator integrated with P-CoS and carbon nanotubes effectively suppresses the polysulfide shuttle and propels the redox kinetics of polysulfides, thus promising higher specific discharge capacity, better rate, and stable cycle performance. Even under the high sulfur loading condition (4.8 mg cm), the areal discharge capacity of the cell with the functional separator can still remain at 4.5 mA h cm after 100 cycles at 0.2 C. More importantly, this work may encourage more effort on anion doping for engineering the polar surface of transition-metal compounds to further mediate the interfacial redox chemistry between transition-metal compounds and polysulfides in Li-S batteries.
锂硫（Li-S）电池因其高达2600 W h/kg的超高能量密度和低成本，被视为最具前景的下一代电池技术之一。然而，Li-S电池的应用仍面临重大挑战，如穿梭效应和缓慢的氧化还原动力学。在此，研究表明磷掺杂不仅能显著提高多硫化物吸附能力，还能增强金属有机框架衍生的CoS纳米盒在Li-S电池中的催化作用。因此，一种集成了P-CoS和碳纳米管的改性隔膜能有效抑制多硫化物穿梭，并推动多硫化物的氧化还原动力学，从而有望实现更高的比放电容量、更好的倍率性能和稳定的循环性能。即使在高硫负载条件（4.8 mg/cm²）下，采用功能性隔膜的电池在0.2 C下循环100次后，其面积放电容量仍可保持在4.5 mA h/cm²。更重要的是，这项工作可能会促使人们在阴离子掺杂方面做出更多努力，以设计过渡金属化合物的极性表面，进一步调节Li-S电池中过渡金属化合物与多硫化物之间的界面氧化还原化学。
