Nb-doped Li1.20[Mn0.54Ni0.13Co0.13]O2 cathode material with enhanced electrochemical properties for lithium-ion battery

Abstract

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 Li1.20[Mn0.54Ni0.13Co0.13]O2 via using the carbonate co-precipitation method. The effect of the Nb5+ doping modification on the microstructure, morphology and electrochemical properties of the Li1.20[Mn0.54Ni0.13Co0.13]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 Li1.20[Mn0.54Ni0.13Co0.13]0.78Nb0.02O2 delivered about 20.6 mAh g-1 larger than that of the pristine one at 5C high rate. In addition, the Li1.20[Mn0.54Ni0.13Co0.13]0.78Nb0.02O2 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 Li1.20[Mn0.54Ni0.13Co0.13]0.78Nb0.02O2