Consolidating Lithiothermic‐Ready Transition Metals for Li<sub>2</sub>S‐Based Cathodes
Zhenyu Xing, Guoqiang Tan, Yifei Yuan, Bao Wang, Lu Ma, Jing Xie, Ze‐Sheng Li, Tianpin Wu, Yang Ren, Reza Shahbazian‐Yassar, Jun Lü, Xiulei Ji, Zhongwei Chen
Abstract
Abstract Li 2 S holds a promising role as a high‐capacity Li‐containing cathode, circumventing use of metallic lithium in constructing next‐generation batteries to replace current Li‐ion batteries. However, progress of Li 2 S cathode has been plagued by its intrinsic drawbacks, including high activation potentials, poor rate performance, and rapid capacity fading during long cycling. Herein, a series of Li 2 S/transition metal (TM) nanocomposites are synthesized via a lithiothermic reduction reaction, and it is realized that the presence of TMs in Li 2 S matrix can transform electrochemical behaviors of Li 2 S. On the one hand, the incorporation of W, Mo, or Ti greatly increases electronic and ionic conductivity of Li 2 S composites and inhibits the polysulfide dissolution via the TMS bond, effectively addressing the drawbacks of Li 2 S cathodes. In particular, Li 2 S/W and Li 2 S/Mo exhibit the highest ionic conductivity of solid‐phase Li‐ion conductors ever‐reported: 5.44 × 10 −2 and 3.62 × 10 −2 S m −1 , respectively. On the other hand, integrating Co, Mn, and Zn turns Li 2 S into a prelithiation agent, forming metal sulfides rather than S 8 after the full charge. These interesting findings may shed light on the design of Li 2 S‐based cathode materials.