Revealing the effect of Nb5+ on the electrochemical performance of nickel-rich layered LiNi0.83Co0.11Mn0.06O2 oxide cathode for lithium-ion batteries

Structural schematic and morphology comparison plots of the Nb5+-doped nickel-rich layered LiNi0.83Co0.11Mn0.06O2 cathode powders. [Display omitted] •Nb5+ doping provides the stronger Nb-O bond to strengthen structural stability.•NCM-1.0 presents compact secondary particles with more ordered layered structure.•The NCM-1.0 electrode delivers high capacity retention of 86.6 % after 200 cycles.•NCM-1.0 preserves the structural integrity of the secondary particles after cycles. The layered Nb5+-doped LiNi0.83Co0.11Mn0.06O2 (NCM) oxide cathode materials are successfully synthesized through introducing Nb2O5 into the precursor Ni0.83Co0.11Mn0.06(OH)2 during the lithiation process. The results refined by GSAS software present that the Nb5+-doped samples possess the perfect crystal structure with broader Li+ diffusion pathways. Moreover, the morphology characterized by scanning electron microscope displays the compact secondary particles packed by smaller primary particles under the effect of Nb5+. The excellent electrochemical properties are also acquired from the Nb5+-doped samples, in which the optimal rate performance and cycling stability are performed for NCM-1.0 when up to 1.0 mol % of Nb2O5 (based on the precursor) is added. Benefited from the introduction of Nb5+, the cell assembled with the NCM-1.0 electrode retains higher capacity retention of 86.6 % at 1.0 C and 25 °C, and 71.7 % at 1.0 C and 60 °C after 200cycles. Moreover, it also delivers higher discharge specific capacity of 154.6 mAh g−1 at 5.0 C. Therefore, the Nb5+-doping strategy may open an effective route for optimizing nickel-rich oxide cathode materials, which is worth popularizing for the enhancement of the electrochemical performance of nickel-rich cathodes for lithium-ion batteries.