Influence of synthesis conditions on electrochemical properties of high-voltage Li1.02Ni0.5Mn1.5O4 spinel cathode material

Li_1.02Ni_0.5Mn_1.5O₄ spinel cathode materials were successfully synthesized by a citric acid-assisted sol-gel method. The structure and morphology of the materials have been examined by X-ray diffraction and scanning electron microscopy, respectively. Electrochemical properties of the materials were investigated using cyclic voltammetry and galvanostatic charge/discharge measurements at two different temperatures (25 and 55 °C) using lithium anode. The initial capacity and capacity retention are highly dependent on the particle size, particle size distribution, crystallinity and purity of the materials. The Li_1.02Ni_0.5Mn_1.5O₄ materials synthesized both at 800 and 850 °C have shown best electrochemical performance in terms of capacity and capacity retention between 3.5 and 4.9 V with a LiPF₆ based electrolyte.