Nd-doped LiNi0.5Co0.2Mn0.3O2 as a cathode material for better rate capability in high voltage cycling of Li-ion batteries

Layered Nd-doped LiNi0.5Co0.2Mn0.3O2 (NCM523) compounds were successfully synthesized via a coprecipitation-assisted solid-phase method in this work. The effects of Nd doping on the crystal structure, morphology, and electrochemical properties were characterized thoroughly using XRD, SEM, TEM, EDX, and electrochemical tests. Rietveld refinement of the X-ray diffraction data indicated that the Nd-doped samples had lower cation mixing than the raw NCM523. The SEM and EDX mapping characterization results demonstrated that Nd atoms were uniformly distributed in NCM523. At 1C and 10C, the Li(Ni0.5Co0.2Mn0.3)(0.992)Nd0.008O2 materials exhibited initial discharge capacities of 189.7 and 101.5 mAh g (1), respectively, with capacity retentions of 83.3% and 88%, respectively, compared to those of NCM523 (68.1% and 52.5%, respectively) with a cutoff voltage of 4.8 V after 100 cycles. It was found that NCM523 doped with Nd3+ ions can expand lithium ion diffusion channels in the layered structure and stabilize the structure of the material. (C) 2017 Published by Elsevier Ltd.