Hollow microspherical Li[Li0.24Ni0.38Mn0.38]O2 as cathode material for lithium-ion batteries with excellent electrochemical performance

Abstract

Li-rich hollow microspherical Li[Li0.24Ni0.38Mn0.38]O2 sample was successfully synthesized by a coprecipitation approach followed by high-temperature calcinations. The compositions and structures of Li-rich hollow microspherical Li[Li0.24Ni0.38Mn0.38]O2 were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS) and the results revealed that the sample possesses typical a-NaFeO2 layered structures with a weak reflection of LiMnO6, and of hollow microspherical morphology with porous surfaces. Electrochemical measurements showed that the Li-rich hollow microspheres deliver good cycling stabilities and rate capabilities with initial discharge capacities of 229, 213 and 202 mAh g-1 at current density of 340, 680 and 1000 mA g-1, respectively, with fewer capacity above 4.5 V than that of Li-rich spinel-layered Li- Ni-Mn-Co-O cathode materials. The excellent electrochemical performances of hollow microspherical Li-rich Li[Li0.24Ni0.38Mn0.38]O2 could be related to the synergistic effect of wellregulated morphologies and appropriate sizes as well as the porous surfaces.