Synthesis and electrochemical properties of numerous classes of vanadates

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 electrochem ical and in situ X-ray diffraction studies suggest that a mechanism of Li u ptake/removal, different from the usual Li insertion/deinsertion process, i s occurring in these vanadates. (C) 1999 Elsevier Science S.A. All rights r eserved.