Enhanced stability and high-yield LiFePO4/C derived from low-cost iron precursors for high-energy Li-ion batteries

The present work focuses on developing carbon-coated lithium iron phosphate (LFP/C) cathode material from economical, high-dense Fe3O4 iron precursor resulting in good capacity, high atomic economy, and appreciable tap density for lithium-ion battery (LIB) fabrication. In addition, Fe2O3 and Fe were also used as Fe precursor for LFP/C synthesis and the results were compared with Fe3O4-LFP/C. Less gas evolution during heating and high-density precursors resulted in ~20–25% more atomic efficiency and ~1.5 to 1.8 times higher tap density over FeC2O4-LFP/C. Further, the synthesized materials have been characterized for their phase purity, morphology, and oxidation states using various characterization techniques. Electrochemical studies showed that Fe3O4-LFP/C delivers a high capacity of 137 mAh g−1 at 1C when compared with Fe2O3-LFP/C and Fe-LFP/C. Interestingly, Fe3O4-LFP/C retained 83 % capacity after 600 cycles at 1C, illustrating the long cyclic stability. In addition, Fe3O4-LFP/C with the high atomic economy (73%) and tap density equivalent to the commercially available LFP/C paves the path for affordable LFP synthesis for high-energy density batteries. Hence, the LFP/C developed in this work can be used as a cathode material for high-density electrodes that are appropriate for high-energy applications.