Influence of particle size and fluorination ratio of CF(x) precursor compounds on the electrochemical performance of C–FeF(2) nanocomposites for reversible lithium storage

Systematical studies of the electrochemical performance of CF(x)-derived carbon–FeF(2) nanocomposites for reversible lithium storage are presented. The conversion cathode materials were synthesized by a simple one-pot synthesis, which enables a reactive intercalation of nanoscale Fe particles in a CF(x) matrix, and the reaction of these components to an electrically conductive C–FeF(2) compound. The pretreatment and the structure of the utilized CF(x) precursors play a crucial role in the synthesis and influence the electrochemical behavior of the conversion cathode material. The particle size of the CF(x) precursor particles was varied by ball milling as well as by choosing different C/F ratios. The investigations led to optimized C–FeF(2) conversion cathode materials that showed specific capacities of 436 mAh/g at 40 °C after 25 cycles. The composites were characterized by Raman spectroscopy, X-Ray diffraction measurements, electron energy loss spectroscopy and TEM measurements. The electrochemical performances of the materials were tested by galvanostatic measurements.