Effect of structural and electrochemical properties of different Cr-doped contents of Li[Ni1/3Mn1/3Co1/3]O2

Layered Li [Ni(1-x)/3Mn(1-x)/3Co(1-x)/3Crx]O-2 materials with x = 0, 0.0 1, 0.02, 0.03, 0.05 are prepared by a solid-state pyrolysis method. The oxide compounds were calcined with various Cr-doped contents, which result in greater difference in morphological (shape, particle size and specific surface area) and the electrochemical (first charge profile, reversible capacity and rate capability) differences. The Li[Ni(1-x)/3Mn(1-x)/3Co(1-x)/3Crx]O-2 powders were characterized by means of X-ray diffraction (XRD), charge/discharge cycling, cyclic voltammetry, and SEM. XRD experiment revealed that the Li[Ni(1-x)/3Mn(1-x)/3Co(1-x)/3Crx]O-2 (x=0, 0.01, 0.02, 0.03, 0.05) were crystallized to well layered alpha-NaFeO2 structure. The first specific discharge capacity and coulombic efficiency of the electrode of Cr-doped materials were higher than that of pristine material. When x = 0.02, the sample showed the highest first discharge capacity of 241.9 mAh (g-1) at a current density of 30 mA g(-1) in the voltage range 2.3-4.6 V, and the Cr-doped samples exhibited higher discharge capacity and better cycleability under medium and high current densities at room temperature. (c) 2006 Elsevier Ltd. All rights reserved.