锂(药物)
锂离子电池
电解质
锂电池
电极
无机化学
阳极
复合数
磷酸铁锂
磷酸钒锂电池
作者
Shinya Tawa,Yuta Sato,Yuki Orikasa,Kazuhiko Matsumoto,Rika Hagiwara
标识
DOI:10.1016/j.jpowsour.2018.11.046
摘要
Abstract Owing to their high theoretical capacity, metal fluorides have attracted significant interest as materials for fabricating the cathode of lithium secondary batteries. In the present study, a nanocomposite of LiF and FeF2 is prepared by a fluorolytic sol–gel method in an ethanol solution, for use as the cathode material of a lithium secondary battery. The produced LiF/FeF2 composite is characterized by broad X-ray diffraction peaks attributed to the nanosized (∼10 nm) LiF and FeF2 crystals, a large Brunauer–Emmett–Teller surface area of 119 m2 g-1, and adsorption–desorption hysteresis, attributed to the presence of mesopores. The results of charge–discharge tests indicates an initial discharge capacity of 225 mAh (g-LiF/FeF2)−1 through reversal conversion at a current rate of 10 mA (g-LiF/FeF2)−1. Based on a combination of galvanostatic intermittent titration, X-ray absorption, and X-ray diffraction investigations, a new reaction mechanism is developed, namely, the conversion of the local environment of an Fe atom from a rutile-type FeF2 structure to a rhenium trioxide-type FeF3 structure during charging, with the subsequent discharge resulting in the insertion of Li+ into the rhenium trioxide-type FeF3 structure, followed by the conversion reaction to LiF and FeF2.
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