Mechanochemical Synthesis of Li(2)MnO(3) Shell/LiMO(2) (M = Ni, Co, Mn) Core-Structured Nanocomposites for Lithium-Ion Batteries

Core/shell-like nanostructured xLi(2)MnO(3)·(1−x)LiMO(2) (M = Ni, Co, Mn) composite cathode materials are successfully synthesized through a simple solid-state reaction using a mechanochemical ball-milling process. The LiMO(2) core is designed to have a high-content of Ni, which increases the specific capacity. The detrimental surface effects arising from the high Ni-content are countered by the Li(2)MnO(3) shell, which stabilizes the nanoparticles. The electrochemical performances and thermal stabilities of the synthesized nanocomposites are compared with those of bare LiMO(2). In particular, the results of time-resolved X-ray diffraction (TR-XRD) analyses of xLi(2)MnO(3)·(1−x)LiMO(2) nanocomposites as well as their differential scanning calorimetry (DSC) profiles demonstrate that the Li(2)MnO(3) shell is effective in stabilizing the LiMO(2) core at high temperatures, making the nanocomposites highly suitable from a safety viewpoint.