Cathode materials derived from Li2RuO3, Li2ZrO3 and LiNiO2 have been evaluated in lithium cells at room temperature as part of an ongoing study of composite xLiMO(2).(1 - x)Li2M'O-3 electrodes. Our results confirm previous reports that two lithium ions can be initially extracted from Li2RuO3, but that only one lithium ion can be cycled between 4.4 and 2.8 V with a rechargeable capacity of approximately 200 mAh/g. Extending the voltage window to 4.6-1.4 V increases the reversible capacity of the Li2RuO3 electrode significantly, to nearly 300 mAh/g. Similar capacities are obtained from a Zr-substituted electrode, Li2Ru1 -yZryO3 for y = 0.1, with excellent cycling stability. A composite electrode, 0.7LiNiO(2).0.3Li(2)RuO(3), provides a steady 150 mAh/g when cycled between 4.6 and 2.7 V. (C) 2003 Elsevier Science B.V. All rights reserved.