Submicro-sized LiMn₂O₄ prepared by a sol–gel, spray-drying method

Abstract

Submicro-sized LiMn₂O₄ powders were produced by a sol–gel, spray-drying method in which a brown gel precursor was prepared via the reaction of LiOH alkaline solution with 1 M Mn(CH₃COO)₂. The gel precursor was then transferred into a dry precursor powder via a spray-dry process. After heating treatment the spinel LiMn₂O₄ powder was obtained. The composition and the crystal size of the samples were strongly affected by the spray speed in the drying process and the heating temperature. The structure and the morphology of LiMn₂O₄ powder were investigated by DTA, TGA, IR, XRD and SEM methods. It was discovered that submicro-sized LiMn₂O₄ powder could be formed under the conditions of rotating spray speed of 15 000 rpm and syntheses temperature of 700 °C. The electrochemical properties of LiMn₂O₄ samples in 1 M LiPF₆, EC:DMC = 1:1 solution were tested by measuring the voltammograms and charge–discharge curves. The submicro-sized LiMn₂O₄ sample made at 700 °C has a capacity of 128 mAh g⁻¹ and good cycle stability for Li⁺ intercalation reaction. This method may be applied to the industrial-scale production of superfine LiMn₂O₄ powder for use in lithium ion batteries.