The electrochemical property of Keggin type hetero polyoxomolybdate K(3)[PMo(12)O(40)](KPM) as the cathode electrode material for lithium battery was examined. KPM showed charge-discharge performance in the potential region from 4.2 V to 1.5 V with capacity of over 200 mAh g(-1). From the result of the ex situ XRD measurement, it is presumed that the electrochemical reaction of KPM proceeds via the lithium (de-)intercalation. The cycle performance of KPM is largely dependent on the charge-discharge potential range. The capacity fade caused by deep discharging seems to be concerned to the < to (R) isomerization of KPM. (C) 2010 Elsevier B.V. All rights reserved.