Synthesis of LiNi0.5Mn1.5O4 Hollow Microspheres and Their Lithium-Storage Properties

High-voltage LiNi0.5Mn1.5O4 hollow microspheres have been synthesized through a facile solid-state method. X-ray diffraction and scanning electron microscopy results reveal that the as-prepared LiNi0.5Mn1.5O4 microspheres are constructed with nanometer-sized primary particles. The effects of the precursors on the morphologies and electrochemical properties of LiNi0.5Mn1.5O4 materials are systematically investigated. Electrochemical test results demonstrate that the materials with large porosity and smaller second particles exhibit higher reversible capacity as well as better cycle stability and rate capacities. LiNi0.5Mn1.5O4 prepared from MnCO3 precursors delivers high reversible capacities of 135.5, 147.5, and 132.1mAhg(-1) at 0.1, 0.5, and 2C, respectively. Even at a high rate of 5C, the electrode retains 93.4% of the initial capacity at 0.1C. Moreover, the electrode shows excellent cycle stability with a discharge capacity of 110mAhg(-1) at 1C after 80cycles at elevated temperature. The extremely attractive electrochemical properties are closely related to the unique structure and chemistry of the synthesized material.