The electrochemical behavior of xLiNiO2·(1 − x)Li2RuO3 and Li2Ru1−yZryO3 electrodes in lithium cells

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 2.8 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, 0.7LiNiO2·0.3Li2RuO3, provides a steady 150 mAh/g when cycled between 4.6 and 2.7 V.