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 xLiMO2·(1−x)Li2M′O3 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 2.8V with a rechargeable capacity of approximately 200mAh/g. Extending the voltage window to 4.6–1.4V increases the reversible capacity of the Li2RuO3 electrode significantly, to nearly 300mAh/g. Similar capacities are obtained from a Zr-substituted electrode, Li2Ru1−y Zr y O3 for y=0.1, with excellent cycling stability. A composite electrode, 0.7LiNiO2·0.3Li2RuO3, provides a steady 150mAh/g when cycled between 4.6 and 2.7V.