Enhancement of electrochemical properties of niobium‐doped LiFePO₄/C synthesized by sol–gel method

LiFePO 4 /C and LiFe 1– x Nb x PO 4 /C composites were synthesized using a sol–gel method. The influence of niobium doping on the constitution, morphology, and electrochemical properties of the samples was studied in detail. X‐Ray diffraction patterns indicate that appropriate Nb doping does not alter seriously the structure of LiFePO 4 . Electrochemical characterization of the electrodes showed that the Li‐ion batteries based on LiFe 1– x Nb x PO 4 /C electrode exhibited better charge/discharge performance than those based on LiFePO 4 /C. The LiFe 0.95 Nb 0.05 PO 4 /C‐based cell had the specific capacity of 157, 121, and 85 mAh/g at 0.2, 2, and 5 C, respectively, in comparison with 126, 94, and 52 mAh/g for the LiFePO 4 /C cell. The results show that the addition of niobium promotes the electrochemical performance of the materials especially at high charge/discharge rates of the battery.