Manganese oxyiodide thin films as a cathode material were prepared by pulsed laser reactive deposition in an oxygen ambient. An oxyiodide film electrode with good electrochemical properties was prepared at the substrate temperature Ts = 200 degreesC and 200 mTorr oxygen ambient using a target with a NaI/Li2MnO3 molar ratio of 0.15. This film electrode exhibited a specific capacity of 240 mAh/g in the range 4.5-1.5 V and the capacity fade was less than 10% after 40 cycles. In addition, the diffusion of lithium ion into the manganese oxyiodide film was measured using the ac impedance method, and the chemical diffusion coefficient for the film was estimated to be of the order of 10(-9) to 10(-10) cm(2) s(-1).