Nb-doped Li_1.20[Mn_0.54Ni_0.13Co_0.13]O₂ cathode material with enhanced electrochemical properties for lithium-ion battery

To enhance the electrochemical properties and structure stability of the Layered Li-rich Mn-based oxides, the Nb⁵⁺ with different contents were doped into the Li_1.20[Mn_0.54Ni_0.13Co_0.13]O₂ via using the carbonate co-precipitation method. The effect of the Nb⁵⁺ doping modification on the microstructure, morphology and electrochemical properties of the Li_1.20[Mn_0.54Ni_0.13Co_0.13]O₂ cathode have been investigated by the XRD, SEM, XPS, galvanostatic discharge-charge tests and electrochemical impedance spectroscopy (EIS) techniques. The results demonstrated the Nb⁵⁺ doping not only could enhance the cation order degree, but also contributed to enhancing the Li+ migration speed during cycling. The Li_1.20[Mn_0.54Ni_0.13Co_0.13]_0.78Nb_0.02O₂ delivered about 20.6 mAh g-1 larger than that of the pristine one at 5C high rate. In addition, the Li_1.20[Mn_0.54Ni_0.13Co_0.13]_0.78Nb_0.02O₂ retained a much higher discharge capacity retention of 92.5% after 100 cycles. Whereas, the pristine cathode showed only 85.7% of the capacity retention under identical conditions. These results indicated that Nb5+ doping modification could effectively enhance the electrochemical properties of Li_1.20[Mn_0.54Ni_0.13Co_0.13]_0.78Nb_0.02O₂