Preparation of neodymium‐doped LiMnPO4/C cathode by sol‐gel method with excellent electrochemical performance for lithium‐ion batteries

Summary The porous spherical structure neodymium‐doped LiMn1−xNdxPO4/C nanoparticles have been prepared through glycolic acid‐assisted sol‐gel method. The neodymium‐ion doping effect on the crystalline microstructure, crystal appearance, and electrochemical parameters of LiMnPO4/C cathodes have been detected by X‐ray diffractometer (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), charge and discharge test, cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS) method. XRD patterns show that a proper amount of neodymium‐ion doping could not change the host crystal structure; combined with EDS spectra, we could conclude that Nd3+ has successful embedding into the lattice structure of LiMnPO4/C. SEM analysis shows that the LiMn0.94Nd0.06PO4/C sample has the uniform and fine particles diameter distribution in comparison with other doped samples. The electrochemical measurement results indicate that the LiMn0.94Nd0.06PO4/C has the initial discharge specific capacity of 155.2 mAh/g at 0.05 C discharge rate; after 200 cycles, the capacity value reduces slightly to 138.7 mAh/g, the capacity retention rate is maintained at 89.4%. The LiMn0.94Nd0.06PO4/C has high‐rate discharge performance with the specific capacity value of 128.0 mAh/g (10 C). The results conclude that a proper amount of neodymium‐ion doping ratio could effectively enhance the lithium‐ion diffusivity and improve high‐rate performance of LiMnPO4 cathode materials. The LiMn0.94Nd0.06PO4/C nanoparticles with porous spherical structure were prepared by modified sol‐gel method. Enhancement in microstructure and electrochemical properties by a proper neodymium‐ion doping ratio was investigated in details. The neodymium‐ion doping effect on charge transport kinetics of LiMnPO4/C materials was studied.