Layered Li2RuO3–LiCoO2 composite as high-performance cathode materials for lithium-ion batteries

• Li2RuO3-LiCoO2 composite was synthesized by solid-state reaction method.
• Li2RuO3-LiCoO2 composite contains two redox actives during the reaction.
• Li2RuO3-LiCoO2 composite can be as high performance cathode for LIBs.

Lithium-rich transition metal oxides are attractive cathode materials providing high energy densities for lithium-ion batteries. A layer-structured Li2RuO3-LiCoO2 composite was synthesized by the solid-state reaction method. In the as-prepared composite, Li2RuO3 component not only serves as the electrochemical active phase providing large reversible capacity, but also improves the structural stability of layered LiCoO2 at high potential. Electrochemical measurements show the composite has high reversible specific capacity and good capacity retention. Particularly, the initial discharge specific capacity can reach 240 mA h/g at current density of 0.13 C between 2.0 V and 4.5 V. It also exhibits an excellent cycling stability with capacity retention of 75% after 50 cycles. The present work suggests choosing appropriate transition metal M and M′ for Li2MO3-LiM′O2 composite should be an efficient strategy for designing new cathode materials.