Solid-State Chemistry and Electrochemistry of LiCo1 ∕ 3Ni1 ∕ 3Mn1 ∕ 3O2 for Advanced Lithium-Ion Batteries: II. Preparation and Characterization

Abstract

was prepared and characterized by scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), electron diffraction (ED), X-ray diffraction (XRD), and X-ray absorption fine structure (XAFS) to examine whether or not our first-principles calculation properly predicted a new lithium insertion material of . High-resolution TEM image directly showed the layered structure having a cubic close-packed oxygen array. The [00.1]-zone electron diffraction pattern showed a -type superlattice ordering in the transition metal layers. Rietveld analysis of powder XRD indicated that a structural model with a space group symmetry of to present a -type superlattice based on -structural type was adequate rather than that simply formulated with . The Me-O bond lengths, i.e., 1.93, 2.03, and , respectively, for Co, Ni, and Mn, obtained by -edge EXAFS, were compared with those calculated from structural data determined by XRD assuming and also with those of the first-principles calculation. These values were consistent with each other, which indicated that was a superlattice structure (; , and ) consisting of , , and .