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Tailoring the Redox Reactions for High‐Capacity Cycling of Cation‐Disordered Rocksalt Cathodes
Advanced Functional Materials ( IF 18.5 ) Pub Date : 2021-01-27 , DOI: 10.1002/adfm.202008696
Yuan Yue 1 , Ning Li 1 , Yang Ha 2 , Matthew J. Crafton 3 , Bryan D. McCloskey 1, 3 , Wanli Yang 2 , Wei Tong 1
Affiliation  

Cation‐disordered rocksalts (DRXs) have emerged as a new class of high‐capacity Li‐ion cathode materials. One unique advantage of the DRX chemistry is the structural flexibility that substantially lessens the elemental constraints in the crystal lattice, such as Li content, choice of transition metal redox center paired with appropriate d0 metal, and incorporation of F anion, which allows optimization of the key redox reactions. Herein, a series of the DRX oxyfluorides based on the Mn redox have been designed and synthesized. By tailoring the stoichiometry of the DRX compositions, high‐capacity cycling by promoting the cationic Mn2+/Mn4+ redox reactions while suppressing those from anionic O is successfully demonstrated. A highly fluorinated DRX compound, Li1.2Mn0.625Nb0.175O1.325F0.675 (M0.625F0.675), delivers a capacity of ≈170 mAh g−1 at C/3 for 100 cycles. This work showcases the concept of balancing the cationic and anionic redox reactions in the DRX cathodes for improved electrochemical performance through the rational composition design.

中文翻译:

量身定制氧化还原反应,以实现阳离子无序岩盐阴极的大容量循环

阳离子无序岩石盐(DRXs)已经成为一类新型的高容量锂离子阴极材料。DRX化学的一个独特优势是结构上的灵活性,它大大减少了晶格中的元素约束,例如Li含量,过渡金属氧化还原中心与合适的d 0金属配对的选择以及F阴离子的掺入,这可以优化关键的氧化还原反应。本文中,已经设计并合成了一系列基于Mn氧化还原的DRX氟氧化物。通过调整DRX组成的化学计量,通过促进阳离子Mn 2+ / Mn 4+进行大容量循环成功地证明了氧化还原反应同时抑制了阴离子O的氧化还原反应。高度氟化的DRX化合物Li 1.2 Mn 0.625 Nb 0.175 O 1.325 F 0.675(M 0.625 F 0.675)在100个循环下的C / 3容量约为170 mAh g -1。这项工作展示了通过合理的成分设计来平衡DRX阴极中阳离子和阴离子氧化还原反应的概念,以提高电化学性能。
更新日期:2021-04-01
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