Structural and electrochemical properties of Nd-doped LiFePO4/C prepared without using inert gas

To further improve the electrochemical performance of LiFePO4/C, Nd doping has been adopted for cathode material of the lithium ion batteries. The Nd-doped LiFePO4/C cathode was synthesized by a novel solid-state reaction method at 750 °C without using inert gas. The Li0.99Nd0.01FePO4/C composite has been systematically characterized by X-ray diffraction, EDS, SEM, TEM, charge/discharge test, electrochemical impedance spectroscopy and cyclic stability. The results indicate that the prepared sample has olivine structure and the Nd3+ and carbon modification do not affect the structure of the sample but improve its kinetics in terms of discharge capacity and rate capability. The Li0.99Nd0.01FePO4/C powder exhibited a specific initial discharge capacity of about 161 mAh g− 1 at 0.1 C rate, as compared to 143 mAh g− 1 of LiFePO4/C. At a high rate of 2 C, the discharge capacity of Li0.99Nd0.01FePO4/C still attained to 115 mAh g− 1 at the end of 20 cycles. EIS results indicate that the charge transfer resistance of LiFePO4/C decreases greatly after Nd doping.

Research Highlights
► The Nd-doped LiFePO4/C was successfully synthesized without using inert gas.
► C coating and Nd doping are adopted to improve the performance of LiFePO4.
► Nd-doped LiFePO4/C exhibited excellent electrochemical performance.