Electrochemical properties of Li(Li(1-x)/3CoxMn(2-2x)/3)O2 (0 ≤ x ≤ 1) solid solutions prepared by poly-vinyl alcohol (PVA) method

The whole range of solid solutions Li(Li(1-x)/3CoxMn(2-2x)/3)O-2 (0 <= X <= 1) was firstly synthesized by an aqueous solution method using poly-vinyl alcohol as a synthetic agent to investigate their structure and electrochemical properties. X-ray diffraction results indicated that the synthesized solid solutions showed a single phase without any detectable impurity phase and have a hexagonal structure with some additional peaks caused by monoclinic distortion, especially in the solid solutions with a low Co amount. In the electrochemical examination, the solid solutions in the range between 0.2 <= x <= 0.9 showed higher discharge capacity and better cyclability than LiCoO2 (X = 1) on cycling between 2. 0 and 4.6 V with 100 mA g(-1) at 25 degrees C. For example, Li(Li0.2Co0.4Mn0.4)O-2 (x = 0.4) exhibited a high discharge capacity of 180 mA h g(-1) at the 50th cycle. By synthesizing the solid solution between Li2MnO3 and LiCoO2, the electrochemical properties of the end members were improved. (c) 2006 Elsevier B.V. All rights reserved.