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

Abstract

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 240mAh/g at current density of 0.13C between 2.0V and 4.5V. 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.