Enhanced Redox Electrocatalysis in High-Entropy Perovskite Fluorides by Tailoring d–p Hybridization

• Published in: Nano-micro letters 2024-12, Vol.16 (1), p.55-18, Article 55
• Main Authors: Li, Xudong, Qiang, Zhuomin, Han, Guokang, Guan, Shuyun, Zhao, Yang, Lou, Shuaifeng, Zhu, Yongming
• Format: Article
• Language: English
• Subjects: Catalysts; Catalytic kinetics; Discharge; d–p orbital hybridization; Electrocatalysis; Electrocatalysts; Engineering; Entropy; Entropy effect; Fluorides; Hybridization; KCoMnNiMgZnF3-HEC perovskite fluoride; Lithium batteries; Lithium–oxygen batteries; Mass transfer; Nanoscale Science and Technology; Nanotechnology; Nanotechnology and Microengineering; Nucleation; Perovskites; Reaction intermediates; Reaction kinetics
• ISSN: 2311-6706; 2150-5551; 2150-5551
• DOI: 10.1007/s40820-023-01275-3

Highlights The tailored KCoMnNiMgZnF 3 -HEC cathode delivers extremely high discharge capacity (22,104 mAh g −1 ), outstanding long-term cyclability (over 500 h), preceding majority of traditional catalysts reported. Entropy effect of multiple sites in KCoMnNiMgZnF 3 -HEC engenders appropriate regulation of 3 d orbital structure, leading to a moderate hybridization with the p orbital of key intermediate. The homogeneous nucleation of Li 2 O 2 is achieved on multiple cation site, contributing to effective mass transfer at the three-phase interface, and thus, the reversibility of O 2 /Li 2 O 2 conversion. High-entropy catalysts featuring exceptional properties are, in no doubt, playing an increasingly significant role in aprotic lithium-oxygen batteries. Despite extensive effort devoted to tracing the origin of their unparalleled performance, the relationships between multiple active sites and reaction intermediates are still obscure. Here, enlightened by theoretical screening, we tailor a high-entropy perovskite fluoride (KCoMnNiMgZnF 3 -HEC) with various active sites to overcome the limitations of conventional catalysts in redox process. The entropy effect modulates the d -band center and d orbital occupancy of active centers, which optimizes the d – p hybridization between catalytic sites and key intermediates, enabling a moderate adsorption of LiO 2 and thus reinforcing the reaction kinetics. As a result, the Li–O 2 battery with KCoMnNiMgZnF 3 -HEC catalyst delivers a minimal discharge/charge polarization and long-term cycle stability, preceding majority of traditional catalysts reported. These encouraging results provide inspiring insights into the electron manipulation and d orbital structure optimization for advanced electrocatalyst.