Li(1.2)Mn(0.6)Ni(0.1)Co(0.1)O2 microspheres constructed by hierarchically arranged nanoparticles as lithium battery...

Novel lithium-rich layered Li(1.2)Mn(0.6)Ni(0.1)Co(0.1)O2 microspheres containing hierarchically arranged and interconnected nanostructures have been synthesized by a combination of template-free co-precipitation and solid-state methods. The in situ formed γ-MnO2 spherical template upon co-precipitation gets sacrificed during the course of solid-state fusion of cobalt, nickel and lithium precursors to produce the title compound in the form of microspheres constructed by nanoparticles as building blocks. Porous and hollow microspheres of Li(1.2)Mn(0.6)Ni(0.1)Co(0.1)O2 are formed out of the spontaneous aggregation of nanoparticles, obtained from the custom-designed synthesis protocol. The growth mechanism of Li(1.2)Mn(0.6)Ni(0.1)Co(0.1)O2 spheres could be understood in terms of the Kirkendall effect and Ostwald ripening. The nanocrystalline Li(1.2)Mn(0.6)Ni(0.1)Co(0.1)O2 compound is obtained as a solid solution consisting of rhombohedral R3[combining macron]m and monoclinic C2/m group symmetries, as evidenced by XRD, Raman spectra and HRTEM equipped with FFT and STEM. The currently synthesized Li(1.2)Mn(0.6)Ni(0.1)Co(0.1)O2 cathode exhibits an appreciable discharge capacity of 242 mA h g(-1) at a current density of 50 mA g(-1), due to the synergistic effect of the capacity obtained from the rhombohedral and monoclinic phases.