Enhanced Electrochemical Performance of Rare Earth‐Doped Amorphous LiFePO4 Cathodes for Lithium‐Ion Batteries

Abstract

Neodymium‐doped amorphous LiFePO4/C cathodes formulated as LiFe1−xNdxPO4 (where x = 0, 0.02, 0.05, 0.08, labeled as LF1−xNxP) are synthesized by a solid‐station reaction. Herein, the influence of Nd doping on the amorphous structure, morphology, and electrochemical performance of LiFePO4/C is examined. The thermal and phase stability (ΔT) is analyzed using differential thermal analysis and proves thermal stability is enhanced by doping rare‐earth elements (Nd). The amorphous olivine LiFePO4 phase is identified from X‐ray diffraction peaks and it is demonstrated that neodymium carbon modification does not affect the structure of the sample but improves its kinetics in terms of discharge capacity and rate capability. The LF0.95N0.05P cathode shows the highest initial charge capacity (150 mAh g−1) and discharge capacity (147 mAh g−1) recorded at 0.1 C rate, the cyclic stability continues, and 91.33% of Coulombic efficiency even up to 500 cycles is achieved. The electrochemical impedance spectroscopy provides clearly that neodymium substituting reduces the charge transfer impedance and improves the lithium‐ion diffusion through the structure stability and the electrochemical performances of LiFePO4/C are highly improved by Nd doping.