Yang Qin, Shen Shiying, Han Zhiyuan, Li Guanwu, Liu Dong, Zhang Qingchun, Song Lixian, Wang Dong, Zhou Guangmin, Song Yingze
State Key Laboratory of Environment-Friendly Energy Materials, School of Materials and Chemistry, Southwest University of Science and Technology, Mianyang, 621010, China.
Institute of Applied Physics and Materials Engineering, University of Macau, Macao SAR, 999078, China.
Adv Mater. 2024 Sep;36(36):e2405790. doi: 10.1002/adma.202405790. Epub 2024 Jul 17.
Lithium-sulfur (Li-S) batteries suffer from severe polysulfide shuttle, retarded sulfur conversion kinetics and notorious lithium dendrites, which has curtailed the discharge capacity, cycling lifespan and safety. Engineered catalysts act as a feasible strategy to synchronously manipulate the evolution behaviors of sulfur and lithium species. Herein, a chlorine bridge-enabled binuclear copper complex (Cu-2-T) is in situ synthesized in electrolyte as homogeneous catalyst for rationalizing the Li-S redox reactions. The well-designed Cu-2-T provides completely active sites and sufficient contact for homogeneously guiding the LiS nucleation/decomposition reactions, and stabilizing the lithium working interface according to the synchrotron radiation X-ray 3D nano-computed tomography, small angle neutron scattering and COMSOL results. Moreover, Cu-2-T with the content of 0.25 wt% approaching saturated concentration in electrolyte further boosts the homogeneous optimization function in really operated Li-S batteries. Accordingly, the capacity retention of the Li-S battery is elevated from 51.4% to 86.3% at 0.2 C, and reaches 77.0% at 1.0 C over 400 cycles. Furthermore, the sulfur cathode with the assistance of Cu-2-T realizes the stable cycling under the practical scenarios of soft-packaged pouch cell and high sulfur loading (6.5 mg cm with the electrolyte usage of 4.5 µL mg ).
锂硫（Li-S）电池存在严重的多硫化物穿梭效应、缓慢的硫转化动力学以及臭名昭著的锂枝晶问题，这些问题限制了电池的放电容量、循环寿命和安全性。设计的催化剂是一种同步控制硫和锂物种演变行为的可行策略。在此，一种含氯桥的双核铜配合物（Cu-2-T）在电解液中原位合成，作为均质催化剂用于优化Li-S氧化还原反应。精心设计的Cu-2-T提供了完全活性位点和充分接触，以均匀地引导LiS成核/分解反应，并根据同步辐射X射线3D纳米计算机断层扫描、小角中子散射和COMSOL结果稳定锂工作界面。此外，在电解液中含量为0.25 wt%且接近饱和浓度的Cu-2-T进一步增强了实际运行的Li-S电池中的均匀优化功能。因此，Li-S电池在0.2 C时的容量保持率从51.4%提高到86.3%，在1.0 C下400次循环后达到77.0%。此外，在Cu-2-T的辅助下，硫正极在软包软包电池和高硫负载（6.5 mg cm ，电解液用量为4.5 µL mg ）的实际场景下实现了稳定循环。
