Li Wanli, Chen Kai, Xu Qingchi, Li Xingyun, Zhang Qian, Weng Jian, Xu Jun
Department of Biomaterials, College of Materials, Xiamen University, Xiamen, 361005, China.
Department of Physics, Research Institute for Biomimetics and Soft Matter, Fujian Provincial Key Laboratory for Soft Functional Materials, Xiamen University, Xiamen, 361005, China.
Angew Chem Int Ed Engl. 2021 Sep 20;60(39):21512-21520. doi: 10.1002/anie.202108343. Epub 2021 Aug 20.
One of the major challenges regarding the sulfur cathode of Li-S batteries is to achieve high sulfur loading, fast Li ions transfer, and the suppression of lithium polysulfides (LiPSs) shuttling. This issue can be solved by the development of molybdenum carbide decorated N-doped carbon hierarchical double-shelled hollow spheres (Mo C/C HDS-HSs). The mesoporous thick inner shell and the central void of the HDS-HSs achieve high sulfur loading, facilitate the ion/electrolyte penetration, and accelerate charge transfer. The microporous thin outer shell suppresses LiPSs shuttling and reduces the charge/mass diffusion distance. The double-shelled hollow structure accommodates the volume expansion during lithiation. Furthermore, Mo C/C composition renders the HDS-HSs cathode with improved conductivity, enhanced affinity to LiPSs, and accelerated kinetics of LiPSs conversion. The structural and compositional advantages render the Mo C/C/S HDS-HSs electrode with high specific capacity, excellent rate capability, and ultra-long cycling stability in the composed Li-S batteries.
锂硫电池硫正极面临的主要挑战之一是实现高硫负载、快速锂离子传输以及抑制多硫化锂（LiPSs）穿梭。碳化钼修饰的氮掺杂碳分级双壳空心球（Mo C/C HDS-HSs）的开发可以解决这个问题。HDS-HSs的中孔厚内壳和中心空隙实现了高硫负载，促进了离子/电解质渗透，并加速了电荷转移。微孔薄外壳抑制了LiPSs穿梭，并缩短了电荷/质量扩散距离。双壳空心结构适应了锂化过程中的体积膨胀。此外，Mo C/C组成使HDS-HSs正极具有更高的导电性、对LiPSs更强的亲和力以及加速的LiPSs转化动力学。结构和组成上的优势使Mo C/C/S HDS-HSs电极在组成的锂硫电池中具有高比容量、优异的倍率性能和超长的循环稳定性。
