Peculiar electrochemical behaviors of (1-x)LiNiO2•xLi2TiO3 cathode materials prepared by spray drying

The cathode materials, (1-x)LiNiO(2)(.)xLi(2)TiO(3) with 0.05 less than or equal to x less than or equal to 0.5, were first prepared by a spray drying route. The XRD results indicated that co-substituting Li and Ti for Ni in LiNiO2 Contributes to increasing cations disorder in the materials. Charge-discharge tests in the voltage range of 3.0-4.4 V exhibited expected results: the more simple charge-discharge curves, the deceased capacity and the increased Columbic irreversibility with increasing x. However, when charged up to 4.8 V, the materials with x greater than or equal to 0.075 surprisingly presented unusual electrochemical properties, an excess charge capacity beyond the oxidization of Ni3+ to Ni4+ in materials with the presence of a charge plateau at about 4.5-4.7 V during the initial cycle. These phenomena are very similar to those reported in (1-y)LiNi(0.5)Mn(0.5)O(2)(.)yLi(2)MnO(3) [J. Electrochem. Soc. 149 (2002) A815]. The sample with x = 0.05 indicated promising electrochemical properties in term of capacity and cyclability even charged to 4.8 V. (C) 2003 Elsevier Science B.V. All rights reserved.