Wide-Temperature-Range Li–S Batteries Enabled by Thiodimolybdate [Mo<sub>2</sub>S<sub>12</sub>]<sup>2–</sup> as a Dual-Function Molecular Catalyst for Polysulfide Redox and Lithium Intercalation
Zhiyuan Ma, Wentao Liu, Xinyuan Jiang, Yi Liu, Guang Yang, Zhen Wu, Qiu‐Ping Zhou, Ming Chen, Ju Xie, Lubin Ni, Guowang Diao
Abstract
In lithium–sulfur batteries, a serious obstacle is the dissolution and diffusion of long-chain polysulfides, resulting in rapid capacity decay and low Coulombic efficiency. At present, a common practice is designing cathode materials to solve this problem, but this gives rise to reduced gravimetric and volumetric energy densities. Herein, we present a thiodimolybdate [Mo2S12]2– cluster as sulfur host material that can effectively confine the shuttling of polysulfides and contribute its own capacity in Li–S cells. Moreover, the [Mo2S12]2– cluster as a “bidirectional catalyst” can effectively catalyze polysulfide reduction and lithium sulfide oxidation. We further investigate the catalytic mechanism of [Mo2S12]2– clusters by theoretical calculations, in situ spectroscopic techniques, and electrochemical studies. The (NH4)2Mo2S12/S cathodes show good electrochemical performance under a wide range of temperatures. In addition, a pouch cell fabricated with (NH4)2Mo2S12/S cathodes maintains a stable output for more than 50 cycles.