The lithium intercalation into and deintercalation from Li1-8Al1/4Ni3/4O2 electrode was investigated by using current transient technique under large and small potential steps. From the fact that no potential plateau was observed in the charge-discharge curve, it was inferred that lithium-ion diffusion proceeds in a single phase of the electrode. The ＇reduced＇ current build-up and decay transients upon the large potential stepping were analysed as compared with those current transients numerically simulated under the assumption of the simple finite-length diffusion. From the appearance of the current build-up and decay transients, it was suggested that the Lithium transport through the electrode is mainly governed by the lithium ion diffusivity value during the lithium intercalation as well as deintercalation under the constant potential stepping. Also, the ratio of the transferred charge (Q(int)/Q(deint)) calculated from the measured current build-up and decay transients upon each small potential stepping was discussed in terms of cation mixing between the Ni3+ and Li+ ions in the electrode.