Low Temperature Nanotailoring of Hydrated Compound by Alcohols: FeF3·3H2O as an Example. Preparation of Nanosized FeF3·0.33H2O Cathode Material for Li-Ion Batteries.

Iron fluoride is a kind of high-capacity conversion-type cathode material for lithium-ion batteries (LIBs) and shows attractive practical application potential. However, it still faces many challenges, such as poor electronic conductivity and volume change while cycling. Reducing particle size to nanoscale has been proved to be an effective way to address the poor electronic conductivity and huge volume change of iron fluoride cathodes for LIBs. In this study, a low temperature nanotailoring (LTNT) strategy is proposed to realize the conversion of microsized FeF3·3H2O to nanosized FeF3·0.33H2O by one-step treating with the assistance of alcohols. Meanwhile, the particle size and morphology of iron fluorides can be controlled by regulating the processing conditions. When evaluated as a cathode material for LIBs, the as-prepared bare FeF3·0.33H2O shows a high capacity of 190 mAh g-1 after 50 cycles with excellent rate capability. This LTNT method is applicable to hydrates and even can be extended to easily hydrated compounds.