Facilitating an Ultrastable O3-Type Cathode for 4.5 V Sodium-Ion Batteries via a Dual-Reductive Coupling Mechanism

Tianwei Cui; Longxiang Liu; Yuxuan Xiang; Chuanchao Sheng; Xiang Li; Yongzhu Fu

doi:10.1021/jacs.4c01787

Facilitating an Ultrastable O3-Type Cathode for 4.5 V Sodium-Ion Batteries via a Dual-Reductive Coupling Mechanism

J Am Chem Soc. 2024 May 22;146(20):13924-13933. doi: 10.1021/jacs.4c01787. Epub 2024 May 9.

Authors

Tianwei Cui¹, Longxiang Liu², Yuxuan Xiang³, Chuanchao Sheng⁴, Xiang Li¹, Yongzhu Fu¹

Affiliations

¹ College of Chemistry, Zhengzhou University, Zhengzhou 450001, P. R. China.
² Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH, U.K.
³ Research Center for Industries of the Future, Westlake University, Hangzhou, Zhejiang 310030, P. R. China.
⁴ Center of Energy Storage Materials & Technology, College of Engineering and Applied Sciences, Jiangsu Key Laboratory of Artificial Functional Materials, National Laboratory of Solid State Microstructures and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, P. R. China.

PMID: 38723613
DOI: 10.1021/jacs.4c01787

Abstract

O3-type layered oxides for sodium-ion batteries (SIBs) have attracted extensive attention due to their inherently sufficient Na content, which have been considered as one of the most promising candidates for practical applications. However, influenced by the irreversible oxygen loss and the phase transition of O3-P3, the O3-type cathodes are always limited by low cutoff voltages (typically <4.2 V), restraining the full release of the capacity. In this study, we originally propose a dual-reductive coupling mechanism in a novel O3-type Na_0.8Li_0.2Fe_0.2Ru_0.6O₂ cathode with the suppressed O3-P3 phase transition, aiming at improving the reversibility of oxygen redox at high voltage regions. Consequently, thanks to the formation of the strong covalent Fe/Ru-(O-O) bonding and inhibited slab gliding from the O to P phase, the cathode delivers the preeminent cyclic stability among the numerous O3-type cathodes within a high voltage of 4.5 V (a capacity retention of 95.4% after 100 cycles within 1.5-4.5 V). More importantly, HAADF-STEM and ⁷Li solid-state NMR results reveal the absence of transition metal migration and the presence of reversible Li migration during cycling, which further contributes to the improved structural robustness of the cathode. This study proposes an innovative strategy to boost the reversibility of anionic redox and to achieve stable high-voltage O3-type layered oxides, promoting the further development of SIBs.