Su Yong, Chen Jingzhao, Li Hui, Sun Haiming, Yang Tingting, Liu Qiunan, Ichikawa Satoshi, Zhang Xuedong, Zhu Dingding, Zhao Jun, Geng Lin, Guo Baiyu, Du Congcong, Dai Qiushi, Wang Zaifa, Li Xiaomei, Ye Hongjun, Guo Yunna, Li Yanshuai, Yao Jingming, Yan Jitong, Luo Yang, Qiu Hailong, Tang Yongfu, Zhang Liqiang, Huang Qiao, Huang Jianyu
School of Materials Science and Engineering, Xiangtan University, Xiangtan, Hunan, 411105, P. R. China.
Clean Nano Energy Center, State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao, 066004, P. R. China.
Adv Sci (Weinh). 2022 Jul;9(21):e2201419. doi: 10.1002/advs.202201419. Epub 2022 May 14.
Metals fluorides (MFs) are potential conversion cathodes to replace commercial intercalation cathodes. However, the application of MFs is impeded by their poor electronic/ionic conductivity and severe decomposition of electrolyte. Here, a composite cathode of FeF and polymer-derived carbon (FeF @PDC) with excellent cycling performance is reported. The composite cathode is composed of nanorod-shaped FeF embedded in PDC matrix with excellent mechanical strength and electronic/ionic conductivity. The FeF @PDC enables a reversible capacity of 500 mAh g with a record long cycle lifetime of 1900 cycles. Remarkably, the FeF @PDC can be cycled at a record rate of 60 C with a reversible capacity of 107 mAh g after 500 cycles. Advanced electron microscopy reveals that the in situ formation of stable Fe O layers on the surface of FeF prevents the electrolyte decomposition and leaching of iron (Fe), thus enhancing the cyclability. The results provide a new understanding to FeF electrochemistry, and a strategy to radically improve the electrochemical performance of FeF cathode for lithium-ion battery applications.
金属氟化物（MFs）是有望替代商用嵌入型阴极的转换型阴极材料。然而，MFs因其电子/离子导电性差以及电解质严重分解而阻碍了其应用。在此，报道了一种具有优异循环性能的FeF与聚合物衍生碳的复合阴极（FeF@PDC）。该复合阴极由嵌入具有优异机械强度和电子/离子导电性的PDC基体中的纳米棒状FeF组成。FeF@PDC具有500 mAh g的可逆容量以及创纪录的1900次循环寿命。值得注意的是，FeF@PDC能够以60 C的创纪录倍率进行循环，在500次循环后可逆容量为107 mAh g。先进的电子显微镜显示，FeF表面原位形成的稳定FeO层可防止电解质分解和铁（Fe）的浸出，从而提高了循环稳定性。这些结果为FeF的电化学提供了新的认识，并为从根本上改善用于锂离子电池的FeF阴极的电化学性能提供了一种策略。
