Revealing the effect of Nb on the electrochemical performance of nickel-rich layered LiNiCoMnO oxide cathode for lithium-ion batteries.

The layered Nb-doped LiNiCoMnO (NCM) oxide cathode materials are successfully synthesized through introducing NbO into the precursor NiCoMn(OH) during the lithiation process. The results refined by GSAS software present that the Nb-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 Nb. The excellent electrochemical properties are also acquired from the Nb-doped samples, in which the optimal rate performance and cycling stability are performed for NCM-1.0 when up to 1.0 mol % of NbO (based on the precursor) is added. Benefited from the introduction of Nb, 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 at 5.0 C. Therefore, the Nb-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.