Structural Changes During Lithiation of TiNb2O7

TiNb2O7 with a Wadsley–Roth crystallographic shear structure was prepared by the solid-state synthesis using preliminary mechanical activation. Its structural and electrochemical properties were studied. Order/disorder in the distribution of Ti/Nb over the available metal sites was estimated using XRD and solid-state 93Nb NMR spectroscopy. Electrochemical properties were investigated by galvanostatic cycling. The analysis of Li+ migration pathways in the sample was carried out on the basis of the bond-valence site energy approach (BVSE). Structural changes during chemical lithiation/delithiation of the as-prepared TiNb2O7 were analyzed by XRD and 93Nb and 6,7Li NMR spectroscopy in combination with quantum chemical calculations.