Ultrasonic-assisted synthesis of LiFePO4/C composite for lithium-ion batteries using iron powder as the reactant

The micro-nanosized LiFePO₄/carbon particles have been successfully prepared via a novel mechanical milling process and subsequently carbothermal reduction reaction, using Fe powder, H₃PO₄, Li₂CO₃ and glucose as the reactants. Notably, the milling process is assisted by ultrasonic treatment. XRD, SEM, TEM and particle size detection are operated to investigate the structure, morphology and particle size distribution of the as-prepared products. The electrochemical performances are studied by CV, EIS and cyclic tests. The results show that the LiFePO₄/carbon-ultrasonic-assisted particles are granular and uniformly distributed with high crystallinity, and the mean size of LiFePO₄ powder is about 220 nm. The composite exhibits an excellent electrochemical performance and its initial discharge capacity reaches approximately 156.8, 149, 138, 128 and 119 mAh g⁻¹ at rates of 0.2, 1, 2, 3 and 5 C, respectively. Meanwhile, it can keep the discharge capacity retention of 99.7% over 300 charge/discharge cycles at 1 C.