Compound-Hierarchical-Sphere LiNi_0.5Co_0.2Mn_0.3O₂: Synthesis, Structure, and Electrochemical Characterization

Compound-hierarchical-sphere-structured LiNi_0.5Co_0.2Mn_0.3O₂ was synthesized to improve the electrochemical performance of this material in lithium-ion battery cathodes. The product was found to have a large specific surface area, good electron and ion conductivities, a stable interface, and a robust nano/microhierarchical structure, all of which improved the rate capability, capacity, and cycling stability of this material. When this material was cycled between 3.0 and 4.3 V, a high discharge capacity of 180.8 mA h g^-1 was obtained at 0.2C with 94.0% capacity retention after 100 cycles. In addition, a superior discharge capacity of 148.9 mA h g^-1 was observed at a high current density of 1600 mA g^-1. This compound-hierarchical-sphere LiNi_0.5Co_0.2Mn_0.3O₂ is readily prepared using our ternary coprecipitation method. We also propose an effector unit theory to explain the enhanced cycling stability of this substance and believe that the present results will assist in the design of cathode materials for lithium-ion batteries.