Cascade Catalysis of Zn/Nb Single‐Atom Sites for Wide‐Temperature Li‐S Batteries
Chengkun Zhang, Youzhang Huang, Hui Liu, Tinwei Mo, Hongfei Zheng, Laisen Wang, Jie Lin, Chunhai Jiang, Qingshui Xie, Dong‐Liang PengABSTRACT
Lithium‐sulfur batteries are considered promising next‐generation energy‐storage systems owing to their high theoretical energy density. However, their practical applications are severely hindered by sluggish sulfur redox kinetics and lithium polysulfides (LiPSs) shuttling, which are significantly aggravated under extreme‐temperature conditions. To address this issue, a novel cascade catalysis strategy is developed to regulate the multistep sulfur redox process through embedding the Nb‐N 4 and Zn‐N 4 dual single‐atom sites within N, P co‐doped carbon fibers (Zn/Nb‐NPMCFs). In conjunction with theoretical analysis, it is clarified that Nb single‐atom site preferentially adsorbs soluble LiPSs through forming an Nb‐S bond and catalyzes their conversion, whereas Zn single‐atom site facilitates subsequent Li 2 S‐related redox conversion. With the cascade catalysis effect enabling accelerated sulfur conversion and suppressed LiPSs shuttling, the assembled Li‐S batteries with Zn/Nb‐NPMCFs as free‐standing sulfur hosts deliver good electrochemical performance over a wide temperature range, retaining 651.8 and 401.1 mAh g −1 under 50°C and −20°C at 0.5 C, even after 500 cycles, respectively. This work provides a guideline for improving multistep sulfur redox kinetics in Li‐S batteries.