REVERSIBILITY OF LINIO2 CATHODE

LiNiO2 is a promising cathode material for secondary lithium batteries with a reversible capacity of over 200 mAh g(-1). However, a low cycl e efficiency of about 80% is observed in the first charge-discharge cy cle. To explain this irreversibility, we have assumed a model in which part of the cathode domain becomes electrochemically inactive before the first discharging starts, while the rest remains electrochemically active throughout the cycle. By this model, the active domain is show n to have excellent reversibility. The reversibility in the first cycl e can be improved by limiting the charge capacity. An application of t his model to a LiCoO2 cathode is also described.