Ordered LiNi0.5Mn1.5O4 hollow microspheres as high-rate 5 V cathode materials for lithium ion batteries

Abstract

Ordered LiNi0.5Mn1.5O4 hollow microspheres have been synthesized by an impregnation method followed by a simple solid-state reaction, and their electrochemical performance is investigated as cathode material for lithium ion batteries. The morphologies of the LiNi0.5Mn1.5O4 products prepared at different temperatures reveal that the formation for the hollow structure is tightly relative to the temperature for the solid-state reaction. Then ordered LiNi0.5Mn1.5O4 hollow microspheres are formed under the solid-state reaction temperature of 800°C along with post-annealing at 700°C, but the sample prepared without post-annealing exists at the form of disordered structure. When the ordered LiNi0.5Mn1.5O4 hollow microspheres were applied as the cathode materials for lithium ion batteries, they exhibited superior rate capability (116 mAh g−1 at 5C, 85 mAh g−1 at 10C for charge and discharge) and good cyclability, which are much better than the disordered sample. The durable high-rate capability was attributed to their single-crystal surface configuration that benefits fast Li insertion/extraction kinetics.