Synthesis of Li2MnO3-stabilized LiCoO2 cathode material by spray-drying method and its high-voltage performance

• Li2MnO3 is introduced to stabilize the structure of LiCoO2 at high voltages.
• xLi2MnO3·(1−x)LiCoO2 with fine particles prepared by a simple spray-drying method.
• The modified sample exhibits enhanced high-voltage electrochemical performance.
• Possible kinetic behaviors of the electrode surface are discussed.

xLi2MnO3⋅(1 − x)LiCoO2 (x = 0, 0.02, 0.05, 0.1) as a cathode material for lithium ion batteries has been prepared by a spray-drying assisted solid-state method. The effects of Li2MnO3 content on crystal structure, morphology, and high-voltage electrochemical performance of LiCoO2 have been characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and galvanostatic charge–discharge test. XRD results reveal that all samples have a well-ordered layered structure. SEM and EDS analyses confirm that homogeneous powders with a primary particle size of about 2 μm are observed and the elementals distribute uniformly in the particles. Electrochemical tests demonstrate that the modified samples exhibit obviously enhanced cycling stability in the voltage ranges of 3.0–4.5 V and 3.0–4.6 V, although they deliver somewhat lower discharge capacity. Specifically, 0.02Li2MnO3⋅0.98LiCoO2 delivers the initial discharge capacity of 189.0, 216.8 mA h g−1 at 0.1 C in the voltage range of 3.0–4.5 V and 3.0–4.6 V, respectively, and excellent cycling behaviors at 1 C are achieved.