Dynamic Hosts for High-Performance Li–S Batteries Studied by Cryogenic Transmission Electron Microscopy and in Situ X‑ray Diffraction

• Published in: ACS energy letters Vol. 3; no. 6; pp. 1325 - 1330
• Main Authors: Liu, Xiao-Chen, Yang, Yao, Wu, Jingjie, Liu, Miao, Zhou, Sophia P, Levin, Barnaby D. A, Zhou, Xiao-Dong, Cong, Hengjiang, Muller, David A, Ajayan, Pulickel M, Abruña, Héctor D, Ke, Fu-Sheng
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 08-06-2018; American Chemical Society (ACS)
• Subjects: catalysis (heterogeneous); catalysis (homogeneous); charge transport; defects; ENERGY STORAGE; energy storage (including batteries and capacitors); hydrogen and fuel cells; materials and chemistry by design; membrane; synthesis (novel materials); synthesis (scalable processing); synthesis (self-assembly)
• ISSN: 2380-8195; 2380-8195
• DOI: 10.1021/acsenergylett.8b00561

Developing a high-performance sulfur host is central to the commercialization and general development of lithium–sulfur batteries. Here, for the first time, we propose the concept of dynamic hosts for lithium–sulfur batteries and elucidate the mechanism through which TiS2 acts in such a fashion, using in situ X-ray diffraction and cryogenic scanning transmission electron microscopy (cryo-STEM). A TiS2–S composite electrode delivered a reversible capacity of 1120 mAh g–1 at 0.3 C after 200 cycles with a capacity retention of 97.0% and capacities of 886 and 613 mAh g–1 at 1.0 C up to 200 and 1000 cycles, respectively. Our results indicate that it is Li x TiS2 (0 < x ≤ 1), rather than TiS2, that effectively traps polysulfides and catalytically decomposes Li2S.