Breaking the Passivation Effect for MnO<sub>2</sub> Catalysts in Li−S Batteries by Anion‐Cation Doping
Qingbin Jiang, Huifang Xu, Kwan San Hui, Zhengqing Ye, Chenyang Zha, Lin Zhan, Mengting Zheng, Jun Lü, Kwun Nam Hui
Abstract
Abstract Transition metal oxides (TMOs) are recognized as high‐efficiency electrocatalyst systems for restraining the shuttle effect in lithium‐sulfur (Li−S) batteries, owing to their robust adsorption capabilities for polysulfides. However, the sluggish catalytic conversion of Li 2 S redox and severe passivation effect of TMOs exacerbate polysulfide shuttling and reduce the cyclability of Li−S batteries, which significantly hinders the development of TMOs electrocatalysts. Here, through the anion‐cation doping approach, dual incorporation of phosphorus and molybdenum into MnO 2 (P,Mo‐MnO 2 ) was engineered, demonstrating effective mitigation of the passivation effect and allowing for the simultaneous immobilization of polysulfides and rapid redox kinetics of Li 2 S. Both experimental and theoretical investigations reveal the pivotal role of dopants in fine‐tuning the d‐band center and optimizing the electronic structure of MnO 2 . Furthermore, this well‐designed configuration processes catalytic selectivity. Specifically, P‐doping expedites rapid Li 2 S nucleation kinetics by minimizing reaction‐free energy, while Mo‐doping facilitates robust Li 2 S dissolution kinetics by mitigating decomposition barriers. This dual‐doping approach equips P,Mo‐MnO 2 with robust bi‐directional catalytic activity, effectively overcoming passivation effect and suppressing the notorious shuttle effect. Consequently, Li−S batteries incorporating P,Mo‐MnO 2 ‐based separators demonstrate favorable performance than pristine TMOs. This design offers rational viewpoint for the development of catalytic materials with superior bi‐directional sulfur electrocatalytic in Li−S batteries.