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Layered oxides of general formula Li1+xM1-xO2 (M=d-metal) may exhibit reversible capacities as high as 270mAh/g1, beyond the theoretical capacity due to the oxidation of the cationic component. The most widespread explanation of the phenomenon is the reversible partial oxidation of the anionic sublattice. The mechanism consists in the transferring the charge between the nd-orbitals of the metal and 2p-orbitals of oxygen followed by a formation of covalent O-O bonding. Large nd-O2p orbital overlap makes the 4d and 5d cations most suitable candidates for such mechanism. Recently systems containing fragments of LiMO2 (M=3d-metal) and Li3NbO4 have shown capacity beyond 300mAh/g at 500C2, 3. The mechanism mentioned above cannot apply to these systems as the 3d-orbitals are too small and Nb5+ remains electronically inactive. The scope of our research is to explore in detail this family of Li3NbO4-based electrode materials and investigate structural and electrochemical particularities of (Li3Ni2NbO6)1-x×(Li3NbO4)x for different Li-content. The compounds (LiNi0.66Nb0.33O2)1-x×(Li1.5Nb0.5O2)x have been obtained through a two-step solid state reaction at 9500C in air. With increasing the lithium content, the initially present Ni2+-Nb5+ cation ordering is gradually suppressed driving the crystal symmetry from orthorhombic to cubic. The electrochemical measurements show limited electrochemical activity of the compounds at room temperature, due to slow Li diffusion, but at elevated temperature of 80oC the materials demonstrate reversible capacity of ~100 mAh/g. The influence of the preparation routes on the electrochemical activity of these materials will be discussed and the crystallographic changes at the nanoscale level upon Li deintercalation will be demonstrated.