PERFORMANCE OF TITANIUM DIOXIDE-BASED CATHODES IN A LITHIUM POLYMER ELECTROLYTE CELL

Performance data on two polymorphs of titanium dioxide (anatase and rutile) operating in a lithium polymer electrolyte cell at 120-degrees-C are presented. On the first discharge lithium ions can be electrochemically inserted into both forms to an approximate composition LiTiO2. However, only the rutile material cycles with a significant capacity (approximately 0.5 Li/TiO2) with an average cell voltage of 1.73 V corresponding to a theoretical energy density of approximately 290 W h kg-1. Our results are in contrast to earlier work reported on the intercalation of lithium into these phases at room temperature, where only the anatase form was found to intercalate lithium. X-ray diffraction data indicate that the rutile form undergoes a structural change during the first discharge resulting in the formation of a hexagonal form of LiTiO2.