High‐capacity metal oxide conversion anodes for lithium‐ion batteries (LIBs) are primarily limited by their poor reversibility and cycling stability. In this study, a promising approach has been developed to improve the electrochemical performance of a MoO₂ anode by direct fluorination of the prelithiated MoO₂. The fluorinated anode contains a mixture of crystalline MoO₂ and amorphous molybdenum oxyfluoride phases, as determined from a suite of characterization methods including X‐ray diffraction, Raman spectroscopy, and X‐ray photoelectron spectroscopy, and scanning transmission electron microscopy. Electrochemical measurements indicate that fluorination facilitates the conversion reaction kinetics, which leads to increased capacity, higher coulombic efficiency, and better cycling stability as compared to the nonfluorinated samples. These results suggest that fluorination after prelithiation not only favors formation of the oxyfluoride phase but also improves the lithium‐ion diffusivity and reversibility of the conversion reaction, making it an attractive approach to address the problems of conversion electrodes. These findings provide a new route to design high‐capacity negative electrodes for LIBs.

中文翻译：

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通过二氧化钼（MoO2）直接氟化合成高容量氟氧化物转化阳极。

锂离子电池（LIB）的高容量金属氧化物转化阳极主要受到其可逆性和循环稳定性差的限制。在这项研究中，开发了一种有前途的方法，通过直接氟化预锂化的MoO 2 来提高_{MoO 2}阳极的电化学性能。氟化阳极含有结晶 MoO ₂和无定形氟氧化钼相的混合物，通过一系列表征方法（包括 X 射线衍射、拉曼光谱、X 射线光电子能谱和扫描透射电子显微镜）测定。电化学测量表明，氟化促进了转化反应动力学，与非氟化样品相比，这导致容量增加、库仑效率更高和循环稳定性更好。这些结果表明，预锂化后的氟化不仅有利于氟氧化物相的形成，而且还提高了锂离子的扩散性和转换反应的可逆性，使其成为解决转换电极问题的一种有吸引力的方法。这些发现为设计高容量锂离子电池负极提供了一条新途径。