Gao Wanjie, Liu Yanyu, Cao Chaochao, Zhang Yongguang, Xue Yanming, Tang Chengchun
School of Materials Science and Engineering, State Key Laboratory of Reliability and Intelligence of Electrical Equipment, Hebei University of Technology, Tianjin 300130, China.
Hebei Key Laboratory of Boron Nitride Micro- and Nano-Materials, Hebei University of Technology, Tianjin 300130, China.
J Colloid Interface Sci. 2022 Mar 15;610:527-537. doi: 10.1016/j.jcis.2021.11.095. Epub 2021 Nov 20.
The polysulfides shuttling and slow redox kinetics of sulfur-based cathodes have severely hindered the commercialization of lithium-sulfur (Li-S) batteries. Herein, distinctive three-dimensional microspheres composed of boron nitride (BN) nanosheets and reduced graphene oxide (rGO) were applied to act as efficient sulfur cathode hosts for the first time using in a spray-drying process. Using this construction, the robust microsphere structure could shorten ion diffusion pathways and supply sufficient spaces to alleviate the volumetric expansion of sulfur during lithiation. Besides, the synergistic effect between BN and rGO significantly enhanced polysulfides adsorption capability and accelerated their conversion, verified by the density functional theory (DFT) calculations and adsorption experiments. Consequently, the S-BN@rGO cathode could manifest the high initial capacity (1137 mAh g at 0.2 C) and remarkable cycling/stability performance (572 mAh g at 1 C after 500 cycles). These results shed light on a design concept of high-performance sulfur cathode host materials.
多硫化物穿梭以及硫基阴极缓慢的氧化还原动力学严重阻碍了锂硫（Li-S）电池的商业化进程。在此，由氮化硼（BN）纳米片和还原氧化石墨烯（rGO）组成的独特三维微球首次被应用于喷雾干燥过程中，作为高效的硫阴极主体材料。通过这种结构，坚固的微球结构可以缩短离子扩散路径，并提供足够的空间来缓解锂化过程中硫的体积膨胀。此外，BN和rGO之间的协同效应显著增强了多硫化物的吸附能力并加速了它们的转化，这一点通过密度泛函理论（DFT）计算和吸附实验得到了验证。因此，S-BN@rGO阴极表现出高初始容量（0.2 C时为1137 mAh g）和出色的循环/稳定性性能（500次循环后1 C时为572 mAh g）。这些结果为高性能硫阴极主体材料的设计理念提供了启示。
