A Fluorination Method for Improving Cation‐Disordered Rocksalt Cathode Performance,Advanced Energy Materials

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A Fluorination Method for Improving Cation‐Disordered Rocksalt Cathode Performance
Advanced Energy Materials ( IF 24.4 ) Pub Date : 2020-07-28 , DOI: 10.1002/aenm.202001671
Juhyeon Ahn ₁ , Dongchang Chen ₁ , Guoying Chen ₁

Affiliation

In Li‐rich cation‐disordered rocksalt oxide cathodes (DRX), partial fluorine substitution in the oxygen anion sublattice can increase the capacity contribution from transition‐metal (TM) redox while reducing that from the less reversible oxygen redox. To date, limited fluorination substitution has been achieved by introducing LiF precursor during the solid‐state synthesis. To take full advantage of the fluorination effect, however, a higher F content is desired. In the present study, the successful use of a fluorinated polymeric precursor is reported to increase the F solubility in DRX and the incorporation of F content up to 10–12.5 at% into the rocksalt lattice of a model Li‐Mn‐Nb‐O (LMNO) system, largely exceeding the 7.5 at% limit achieved with LiF synthesis. Higher F content in the fluorinated‐DRX (F‐DRX) significantly improves electrochemical performance, with a reversible discharge capacity of ≈255 mAh g⁻¹ achieved at 10 at% of F substitution. After 30 cycles, up to a 40% increase in capacity retention is achieved through the fluorination. The study demonstrates the feasibility of using a new and effective fluorination process to synthesize advanced DRX cathode materials.

中文翻译：

一种改善阳离子无序岩盐阴极性能的氟化方法

在富含锂的阳离子无序的岩盐氧化物阴极（DRX）中，氧阴离子亚晶格中的部分氟取代可增加过渡金属（TM）氧化还原的容量贡献，同时减少可逆性较低的氧氧化还原的贡献。迄今为止，通过在固态合成过程中引入LiF前驱体已经实现了有限的氟化取代。然而，为了充分利用氟化作用，需要更高的F含量。在本研究中，据报道，氟化聚合物前体的成功使用增加了DRX中F的溶解度，并将Li Mn-Nb-O模型的岩盐晶格中的F含量提高了10–12.5 at％（ LMNO）系统，大大超过了LiF合成所达到的7.5 at％极限。F取代量为10 at％时达到^-1。30个循环后，通过氟化可将容量保持率提高多达40％。这项研究证明了使用新的有效氟化方法合成先进的DRX阴极材料的可行性。

更新日期：2020-09-15

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