Hierarchically-structured nanocrystalline lithium rich layered composites with enhanced rate performances for lithium ion battery

Abstract Li-rich layered composite cathode material: 1/2Li 2 MnO 3 ∙1/2LiMn 1/2 Ni 1/2 O 2 with a hierarchically-structured flake morphology is firstly synthesized with a solvent-controlled organic route. X-ray diffraction evidences a pure lithium-rich layered phase of as-fabricated materials. Transmission electron microscopy investigated that each single flake possesses a highly crystalline nature and it composed by numerous hierarchically-structured plates around 20 nm. Electrochemical performances demonstrates that flake cathode delivered a significantly enhanced rate capability as compared to conventional particles prepared by regular co-precipitation method. The specific capacity of flakes cycled at 0.1 and 1 C were 210 and 155 mAh/g, respectively. Cyclic voltammetry represents distinct intercalation mechanisms between two samples, in which a higher lithium diffusivity is derived by flakes with respect to particle ones. Electrochemical impedance profiles shows that the charge-transfer resistances of flake cathodes could be effectively suppressed with respect to particles after cycled at elevated discharge rates. This study provides an alternative approach for synthesizing morphologically-tailored Li-rich layered cathode and virtually proves the ability to tolerant high current input and can preserve a good cycling retention.