Modification of the LixV2O5 phase diagram by incorporation of chromium oxide

The structural behaviour of the sol-gel chromium-vanadium mixed oxide Cr0.11V2O5.16 is investigated as electrochemical lithium insertion proceeds. Electrochemically reduced electrodes are examined by XRD over the large Li composition range 0 < x ≤ 2 in LixCr0.11V2O5.16. New fingerprints of lithiated phases are obtained in comparison with available data in the Li-V2O5 system. It is shown that lithiation produces an ɛ-related phase over a wide composition range 0.18 ≤ x ≤ 2 whose interlayer distance linearly increases with x which strongly contrasts with the successive appearance of the (α/ɛ), (ɛ/δ), and (δ/γ) wide biphasic regions for the LixV2O5 system. The existence of shorts chains of CrO6 octahedra perpendicular to V2O5 layers increases the three-dimensional character of the host lattice impeding then too strong deformations to occur. These limited structural changes resulting in a single phase behaviour are discussed in relation with the original and promising electrochemical properties of the sol-gel mixed oxide Cr0.11V2O5.16.