Structural and transport properties of layered Li1+x(Mn1/3Co1/3Ni1/3)1-xO2 oxides prepared by a soft chemistry method

In this work structural and transport properties of layered Li1+x(Mn1/3Co1/3Ni1/3)(1-x)O-2 oxides (x=0; 0.03: 0.06) prepared by a "soft chemistry" method are presented. The excessive lithium was found to significantly improve transport properties of the materials, a corresponding linear decrease of the unit cell parameters was observed. The electrical conductivity of Li-1.03(Mn1/3Co1/3Ni1/3)(0.97)O-2 composition was high enough to use this material in a form of a pellet, without any additives, in lithium batteries and characterize structural and transport properties of deintercalated Li1.03-y(Mn1/3Co1/3Ni1/3)(0.97)O-2 compounds. For deintercalated samples a linear increase of the lattice parameter c together with a linear decrease of the parameter a with the increasing deintercalation degree occurred, but only up to 0.4-0.5 mol of extracted lithium. Further deintercalation showed a reversal of the trend. Electrical conductivity measurements performed of Li1.03-y(Mn1/3Co1/3Ni1/3)(0.97)O-2 samples (y = 0.1: 0.3; 0.5; 0.6) showed an ongoing improvement, almost two orders of magnitude, in relation to the starting composition. Additionally, OCV measurements, discharge characteristics and lithium diffusion coefficient measurements were performed for Li/Li+/Li1.03-y(Mn1/3Co1/3Ni1/3)(0.97)O-2 cells. (C) 2008 Elsevier B.V. All rights reserved.