Improved High Rate Capacity and Lithium Diffusion Ability of LiNi1/3Co1/3Mn1/3O2 with Ordered Crystal Structure

A series of LiNi1/3Co1/3Mn1/3O2 samples are synthesized based on the homogeneous precursors formed in ethanol. The cation mixing, Li+ diffusion ability and high rate capacity of LiNi1/3Co1/3Mn1/3O2 materials are studied by XRD, CV and EIS etc. LNCM-24H presents the lowest cation mixing and a well layered crystal structure. High crystallinity and surface area of LNCM-24H is beneficial to the intercalation/deintercalation of Li+ ions, and lead to a high discharge capacity and good cycle ability. By using an equivalent circuit designed on the real components of lithium battery, the kinetic processes of Li+ diffusion are well simulated. LNCM-24H presents the biggest diffusion coefficient of lithium. At 4.4 V, LNCM-24H delivers capacity of 197.9 mAh g(-1) and remains 95% of the initial capacity after 50 cycles, compared with 174.3 and 181.7 mAh g(-1) of LNCM-8H and LNCM-12H, 81% and 84% capacity remained after 50 cycles, respectively. At high current rate of 20 C, LNCM-24H delivers 91.2 mAh g(-1) (about 47% of the initial capacity at 0.1 C rate). After the first cycle, the coulomb efficiency of charge and discharge is stable at 75%. LNCM-24H presents a very well structural stability during cycling at 20 C rate. (C) 2012 The Electrochemical Society. [DOI: 10.1149/2.010205jes] All rights reserved.