In Situ Non‐Topotactic Reconstruction‐Induced Synergistic Active Centers for Polysulfide Cascade Catalysis

• Published in: Advanced functional materials 2023-04, Vol.33 (16), p.n/a
• Main Authors: Zeng, Pan, Zou, Hao, Cheng, Chen, Wang, Lei, Yuan, Cheng, Liu, Genlin, Mao, Jing, Chan, Ting‐Shan, Wang, Qingyuan, Zhang, Liang
• Format: Article
• Language: English
• Subjects: cascade catalyses; Catalysis; Catalytic converters; Electron transitions; energy‐level matching; Heterostructures; in situ reconstruction; Lithium sulfur batteries; Materials science; Molecular orbitals; Polysulfides; Reconstruction; Redox reactions; Sulfur; ternary heterostructures
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.202214770

Most reported catalysts for lithium‐sulfur battery can work for only one of the multiple elementary reactions, thereby resulting in the gradual enrichment of unconverted polysulfides at the catalytic centers and aggravating the shuttle effect. Herein, the concept of cascade catalysis based on a ternary heterostructure, which divides sulfur redox reactions into distinct steps by multiple catalytic centers, is proposed to realize the tandem reduction of Li2S8 to Li2S. As a proof of concept, the ternary heterostructure Na0.67Ni0.25Mn0.75O2(NNMO)‐MnS2‐Ni3S4 achieved by in situ non‐topotactic electrochemical reconstruction successfully integrates three types of active centers into one structure to achieve cascade catalysis. More specifically, NNMO acts as an adsorption mediator to effectively capture polysulfides, MnS2 functions better in catalyzing the conversion of polysulfides into Li2S4 and Ni3S4 demonstrates an enhanced catalytic effect for Li2S precipitation. This synergistic cascade catalysis originates primarily from the dynamic energy‐level matching between the metal d‐band center and the lowest unoccupied molecular orbital of the polysulfides, affording appropriate molecular orbital hybridization and facile interfacial electron transition and thus endowing favorable sulfur reduction kinetics. Eventually, the NNMO‐MnS2‐Ni3S4/S composite electrode exhibits excellent rate performance and high restraining ability toward the polysulfide shuttle under long cycling, high sulfur loading and low electrolyte conditions. The ternary heterostructure achieved by in situ non‐topotactic reconstruction of Na0.67Ni0.25Mn0.75O2 successfully integrates three types of active centers into one structure to achieve cascade catalysis for Li‐S batteries. Such synergistic cascade catalysis is derived from the dynamic evolution of the energy‐level difference between the metal d‐band center and lowest unoccupied molecular orbital of polysulfides, endowing favorable sulfur reduction kinetics.