In this work structural and transport properties of layered Li1+x (Mn1/3Co1/3Ni1/3)1−x O2 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 Li1.03(Mn1/3Co1/3Ni1/3)0.97O2 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)0.97O2 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 0.4–0.5mol of extracted lithium. Further deintercalation showed a reversal of the trend. Electrical conductivity measurements performed of Li1.03−y (Mn1/3Co1/3Ni1/3)0.97O2 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)0.97O2 cells.