Reconversion Reaction of LiF/Fe Composite Thin Film Cathodes for Lithium-Ion Battery

Abstract

The reconversion reaction of lithium fluoride (LiF)/iron (Fe) nanocomposite thin film cathodes prepared with the co-deposition method was investigated at room temperature. The LiF:Fe in molar ratio of 1:1 composite thin film was able to be discharged with large capacity of 300 mAh g⁻¹ after the reconversion reaction on the first charge at 25°C. After the 2nd cycle, it showed relatively stable reversible capacity more than 200 mAh g⁻¹. The discharge profile with 2 V plateau was similar to that of ferrous fluoride (FeF₂), and the trace of FeF₂ was detected in the fully-charged LiF/Fe nanocomposite thin film by X-ray photoelectron spectroscopy (XPS). These results suggest that the reconversion reaction from LiF/Fe to FeF₂ proceeded successfully on the first charge as we expected.