PREPARATION AND LITHIUM INSERTION BEHAVIOR OF OXYGEN-DEFICIENT LI1-DELTA(XV3O8)

Oxygen deficient Li1+xV3O8-delta (0.03 < delta< 0.2) is prepared by re duction of Li1+xV3O8 with carbon. From infrared spectroscopic (IR) stu dies, it is found that specific oxygen is removed from the host lattic e. Electrochemical measurement reveals that more lithium is inserted i n Li1+xV3O8-delta compared with original Li1+xV3O8 contrary to a decre ase in pentavalent vanadium V(V) by the introduction of oxygen defects . This is probably due to the formation of new sites available for the occupation of Li+ ions. During the oxidation process by charging of L i1+xV3O8-delta containing V(IV), Li+ ions are extracted from the octah edral sites and inserted at the initial stage of discharge process. Th ese effects result in an increase in the total amount of inserted lith ium.