Ji-yeon Han

A cathode material for lithium-ion batteries based on graphitized carbon-wrapped FeF3 nanoparticles prepared by facile polymerization

Graphitized carbon-coated FeF3 nanoparticles were synthesized by facile polymerization using FeCl3 as an iron precursor, citric acid (C6H8O7) as a carbon source and chelating agent, and ethylene glycol (EG) as a cross-linker. During the synthesis, Fe(0) was formed in situ to catalyze the formation of graphitic carbon and was subsequently transformed into FeF3. The prepared FeF3/graphitic carbon composite (FC853) exhibited an initial discharge capacity of about 188 mA h g−1, with an excellent capacity fading rate of 0.24% per cycle for 50 cycles at 0.1C in the voltage range of 2.0–4.5 V, which is superior to the corresponding parameters of bare FeF3. This composite also exhibited an increased discharge capacity of about 374 mA h g−1 in the 1st cycle, reaching 421 mA h g−1 after slow activation processes in a wide voltage range of 1.5–4.5 V. In addition, the rate performance of FC853 was significantly improved compared to that of bare FeF3. The enhanced electrochemical Li ion storage properties of this FeF3 composite were mainly attributed to the controlled FeF3 nanoparticle size and the conductive graphitic carbon layers wrapping FeF3 surfaces during prolonged cycles.