Lithium intercalation in electrodeposited vanadium oxide bronzes

By using an electrodeposition method to form hexavanadates, followed by a thermal process, a range of bronze stoichiometries, MxV6O13+y where M: K, Ni, or Mo, 0 < x < 0.5, 0.2 < y < 3.3 in the ternary system of V2O4-V2O5-M2O were prepared. These bronzes adhered well to a conducting substrate and could be directly fabricated into a coin cell without the need for binders or electronic conductors. The phase changes on discharge and the lithium insertion ability were influenced by the amount of the guest metal in the bronze structure. When the value of x was small (<0.5) reversible phase changes resembled those of V2O5 or V6O13 depending on the initial O-2 content of the bronze after heating. The cycle life was adversely affected by the depth of discharge below 2.2 V for the V2O5 type bronzes. The V6O13 bronze cathodes had better cycle lives at average operating voltages of about 2.5 V and over 350 Ah/kg for their initial cycles. Crown Copyright (C) 2003 Published by Elsevier Science B.V. All rights reserved.