Li-rich nickel manganese oxide materials are promising cathode materials for their high theoretical capacity and cobalt-free property. However, the poor cycle and rate performance still hamper their commercial application. In this study, fluorine-doped Li1.2Ni0.2Mn0.6O2 (LNMO) materials have been prepared successfully with different fluorine sources. XRD results verified that the (003) and (104) peaks of F-doped samples slightly shift to the lower diffraction angle than bare LNMO, and the large lithium slab distance of F-doped samples is beneficial for the transport and diffusion of Li+. The sample with PVDF as fluorine sources exhibits the best electrochemical performance than other F-doped LNMO samples. Specifically, this sample exhibits a high discharge capacity of 213.5[Formula: see text]mAh g−1 at 0.2 C (2.0–4.8 V), corresponding to a capacity retention of 88.7% after 100 cycles. The excellent electrochemical performance is due to the substitution of fluorine for oxygen sites with the host lattice, which can significantly enhance the Li+ migration and stabilize the layer structure of LNMO during the cycle process. These results demonstrated that PVDF was the best fluorine source to facilitate the electrochemical property of LNMO.

中文翻译：

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氟源对Li1.2Ni0.2Mn0.6O2正极材料电化学性能的比较

富锂镍锰氧化物材料因其高理论容量和无钴特性而成为很有前途的正极材料。然而，较差的循环和倍率性能仍然阻碍了它们的商业应用。在这项研究中，氟掺杂锂1.2你0.2锰0.6○2（LNMO）材料已成功制备了不同的氟源。XRD结果验证了F掺杂样品的(003)和(104)峰比裸LNMO略微偏移到更低的衍射角，并且F掺杂样品的大锂板距离有利于Li的传输和扩散+. 以 PVDF 作为氟源的样品比其他 F 掺杂的 LNMO 样品表现出最好的电化学性能。具体来说，这个样品表现出213.5的高放电容量[公式：见正文]mAh g-1在 0.2 C (2.0–4.8 V) 下，对应于 100 次循环后的容量保持率为 88.7%。优异的电化学性能是由于氟取代了主晶格的氧位点，这可以显着增强锂+在循环过程中迁移并稳定 LNMO 的层结构。这些结果表明，PVDF 是促进 LNMO 电化学性能的最佳氟源。