Reducing Overpotential of Solid‐State Sulfide Conversion in Potassium‐Sulfur Batteries

• Published in: Angewandte Chemie International Edition 2023-05, Vol.62 (22), p.e202301681-n/a
• Main Authors: Ye, Chao, Shan, Jieqiong, Li, Huan, Kao, Chun‐Chuan, Gu, Qinfen, Qiao, Shi‐Zhang
• Format: Article
• Language: English
• Subjects: Batteries; Bonding strength; Cathodes; Conversion; Copper; Intermediates; Meta-Stable Intermediates; Metal-Sulfur Batteries; Potassium; Single Atom Catalyst; Solid-State Conversion; Sulfide; Sulfides; Sulfur; Sulfur Host; Transition metals
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.202301681

Improving kinetics of solid‐state sulfide conversion in sulfur cathodes can enhance sulfur utilization of metal‐sulfur batteries. However, fundamental understanding of the solid‐state conversion remains to be achieved. Here, taking potassium‐sulfur batteries as a model system, we for the first time report the reducing overpotential of solid‐state sulfide conversion via the meta‐stable S32− intermediates on transition metal single‐atom sulfur hosts. The catalytic sulfur host containing Cu single atoms demonstrates high capacities of 1595 and 1226 mAh g−1 at current densities of 335 and 1675 mA g−1, respectively, with stable Coulombic efficiency of ≈100 %. Combined spectroscopic characterizations and theoretical computations reveal that the relatively weak Cu‐S bonding results in low overpotential of solid‐state sulfide conversion and high sulfur utilization. The elucidation of solid‐state sulfide conversion mechanism can direct the exploration of highly efficient metal‐sulfur batteries. To achieve a superior potassium‐sulfur battery performance, we elucidate the solid‐state K2S3−K2S conversion pathway via meta‐stable intermediates on a range of transition metal single‐atom catalytic sulfur hosts. It is demonstrated that the host with Cu single atom exhibits a relatively weak Cu‐S bonding, resulting in low overpotential of K2S3−K2S conversion. The resultant catalytic sulfur host demonstrates high discharge capacities of 1595 and 1226 mAh g−1 under 335 and 1675 mA g−1, respectively.