STRUCTURAL-CHANGES IN VANADIUM OXIDE-BASED CATHODES DURING CYCLING IN A LITHIUM POLYMER ELECTROLYTE CELL

V6O13 is one of a number of transition metal oxides currently being investigated as potential cathode materials for use in lithium polymer electrolyte batteries. In an attempt to understand the characteristic capacity decline which occurs on cycling V6O13-based cells, we have made a study of the reversibility of the lithium insertion reaction using a post test X-ray diffraction technique. The crystallography of V6O13 in composite cathodes removed from solid-state cells cycled at 120-degrees-C has been determined. X-Ray diffraction data indicate a transformation from crystalline V6O13 to an amorphous material on cycling. Changes in cathode structure during cycling correlate with differences in the shape of the discharge curve.