Wang Zaifa, Tang Yongfu, Fu Xingjie, Wang Jiawei, Peng Zhangquan, Zhang Liqiang, Huang Jianyu
Clean Nano Energy Center, State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004, China.
Hebei Key Laboratory of Applied Chemistry, College of Environmental and Chemical Engineering, Yanshan University, Qinhuangdao 066004, China.
ACS Appl Mater Interfaces. 2020 Dec 16;12(50):55971-55981. doi: 10.1021/acsami.0c17058. Epub 2020 Dec 7.
Understanding polysulfide electrochemistry is critical for mitigation of the polysulfide shuttle effect in Li-S batteries. However, in situ imaging polysulfides evolution in Li-S batteries has not been possible. Herein, we constructed a hollow carbon nanotubule (CNT) wet electrochemical cell that permits real-time imaging of polysulfide evolutions in Li-S batteries in a Cs-corrected environmental transmission electron microscope. Upon discharge, sulfur was electrochemically reduced to long-chain polysulfides, which dissolved into the electrolyte instantly and were stabilized by Py cations solvation. Metastable polysulfides prove to be problematic for Li-S batteries, therefore, destabilizing the Py-solvated polysulfides by adding low polarized solvents into the electrolyte to weaken the interaction between Py cation and long-chain polysulfides renders a rapid polysulfides-to-LiS transition, thus efficiently mitigating polysulfide formation and improving the performance of Li-S batteries dramatically. Moreover, the CNT wet electrochemical cell proves to be a universal platform for in situ probing electrochemistry of various batteries.
了解多硫化物电化学对于减轻锂硫电池中的多硫化物穿梭效应至关重要。然而，对锂硫电池中多硫化物的演变进行原位成像一直无法实现。在此，我们构建了一个中空碳纳米管（CNT）湿式电化学电池，该电池能够在经过Cs校正的环境透射电子显微镜中对锂硫电池中多硫化物的演变进行实时成像。放电时，硫被电化学还原为长链多硫化物，这些多硫化物立即溶解到电解质中，并通过Py阳离子溶剂化作用而稳定。亚稳态多硫化物被证明是锂硫电池的问题所在，因此，通过向电解质中添加低极化溶剂来破坏Py溶剂化多硫化物的稳定性，以减弱Py阳离子与长链多硫化物之间的相互作用，可实现多硫化物向LiS的快速转变，从而有效减轻多硫化物的形成并显著提高锂硫电池的性能。此外，CNT湿式电化学电池被证明是一个用于原位探测各种电池电化学的通用平台。
