Comparison of Synthesized Microstructured and Commercial FePO₄ as Precursors for High-Performance LiFePO₄/C Cathode...

In recent years, lithium iron phosphate (LiFePO₄, LFP) has attracted considerable attention as a cathode material for lithium-ion batteries due to its thermal stability, long cycle life, and low cost. The principal objective of this work was to evaluate the influence of different iron phosphate precursors on the synthesis and electrochemical performance of LiFePO₄/C prepared by a solid-state route. A microstructured FePO₄ obtained by controlled precipitation (FP-S) was compared with two commercially available FePO₄ samples (FP-B1 and FP-B2) and with a synthesis route based on FeSO₄ (FS). All materials showed the formation of phase-pure olivine LiFePO₄, as confirmed by X-ray diffraction (XRD). However, significant differences in particle morphology and crystallinity were observed depending on the precursor source. The material derived from FP-S presented a more homogeneous particle size distribution (2-6 μm) and lower degree of agglomeration compared to the samples obtained from commercial phosphates. Electrochemical performance was evaluated under identical conditions. The best result, in terms of discharge capacity, was 158 mAh/g at 0.1C for the material derived from FP-S. The improved electrochemical response observed for the material prepared from the synthesized FePO₄ indicates that precursor particle size control plays an important role in defining the final microstructure and electrode kinetics. These results suggest that laboratory-designed FePO₄ precursors can provide better performance consistency than commercially available phosphates, where particle size distribution and morphological control are not well-defined.