Fabrication and electrochemical properties of nanorod-shaped LiFePO4 using iron powder as the iron source

Abstract

Abstract In this work, nanorod-shaped LiFePO4 cathode materials are synthesized using an liquid-phase method with reduced iron powder, H3PO4, and LiOH·H2O as source materials. The crystal structure, morphology and electrochemical performance are characterized by X-ray diffraction (XRD), scanning/transmission electron microscope (SEM/TEM), electrochemical test. The results illustrate that Li:Fe:P molar ratio plays an significant role in regulating the morphology and structure of LiFePO4. By modifying the reaction molar ratios, the material undergo a transformation from spherical-shaped nanoparticles to nanorod-shaped. After carbon coating, the LiFePO4/C composite material prepared at 180°C for 12 h with Li:Fe:P ratio 3:1:1.5 displays outstanding electrochemical performance. It achieves a discharge capacity of 120 mAh/g at 1 C, and even after 200 cycles, the capacity retention of this composite material remains above 95%. This method provides a simple, economic and environmentally friendly way to prepare LiFePO4 cathode material for lithium-ion battery.