A vanadium-based cathode for lithium-ion batteries

A vanadium-based oxide system has been developed as a cathode for use in a lithium-ion battery. The lithiated material was made in two steps, i.e., 1, making a Li-V-O and, 2, introducing lithium into the intercalation host by reducing the V(V) with S2- ions in the form of lithium sulfide. The stoichiometry of the final product corresponds approximately to Li4V3O7.9 This material has shown excellent resistance to dissolution in 1 M LiPF6 ethylene carbonate/dimethyl carbonate electrolyte. The capacity of the material cycling at a C/3 rate over the voltage range of 3.8-2.0 V is similar to 220 mAh/g. Li4V3O7.9 has demonstrated some stability in an ambient environment. This new cathode is capable of storing large amounts of energy, 630 mWh/g. Li4V3O7.9 has exhibited long cycle life, greater than 100 deep discharge cycles vs. lithium metal. (C) 2000 The Electrochemical Society. S0013-4651(99)08-019-2. All rights reserved.