Abstract

Background: Lithium-rich layered materials with high discharge capacity are regarded as one of the most promising cathodes for lithium-ion batteries (LIBs). However, they have been suffering from rapid voltage fading and poor rate performance, which impede their practical application.

Methods: Herein, Li_1.2Mn_0.6Ni_0.2O₂ with layered structure was successfully prepared by the ultrasonic dispersion-assisted chemical reduction. X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscope (SEM), transmission electron microscope (TEM) and electrochemical measurements were used to characterize its microstructure and electrochemical properties.

Results: The secondary particles of an as-prepared micro/nanostructured sample consist of irregular and sheet-like rectangular blocks. Electrochemical results show that the initial charge and discharge capacity within 2.0~4.8 V is 337.5 mA h g^-1 and 236.9 mA h g^-1 at 0.2C (1C = 200 mA g^-1). The subsequent discharge capacity is stabilized at about 210 mA h g^-1 for more than 100 cycles. When the current density is increased to 2C, the cycling columbic efficiency is maintained at 99.3% after 100 cycles.

Conclusion: Thus, the Li_1.2Mn_0.6Ni_0.2O₂ cathode material prepared by ultrasonic dispersion-assisted chemical reduction has a promising application in LIBs with high energy density and long cycle life.

Keywords: Cathode, electrochemical properties, layered oxide, lithium-ion battery, rate performance, voltage decay.