Several classes of vanadates can be synthesized by a ＇chimie douce＇ method, which consists of a precipitation reaction occurring at a well-defined pH. An electrochemical investigation has shown that these compounds, depending on their amorphous/crystallized nature, can react with large amounts of Li, leading to reversible capacities as large as 900 mA h/g. Both electrochemical and in situ X-ray diffraction studies suggest that a mechanism of Li uptake/removal, different from the usual Li insertion/deinsertion process, is occurring in these vanadates.