Synthesis and electrochemical properties of LiNi _0.5Mn _1.5O ₄ as a 5 v cathode material for lithium ion batteries

LiNi _0.5Mn _1.5O ₄ as a 5 V cathode material for a lithium-ion battery was synthesized by solution evaporation process in this paper. Thermal gravimetric analysis of the precursor compounds was carried out. X-ray diffraction and scanning electron microscope were used for studying the structure and the morphology of the LiNi _0.5Mn _1.5O ₄ materials. Cyclic voltammograms and charge-discharge curves were obtained for presenting the electrochemical performances of LiNi _0.5Mn _1.5O ₄. Experimental results show that the discharge capacity and capacity retention of the LiNi _0.5Mn _1.5O ₄ prepared by solution evaporation process are superior to the LiNi _0.5Mn _1.5O ₄ obtained by melting salt method. The effects of different sintering temperatures on the electrochemical properties of the LiNi _0.5Mn _1.5O ₄ electrode materials synthesized by a solution evaporation process were also systematically investigated. With the raising of the sintering temperature, the size of the LiNi _0.5Mn _1.5O ₄ gradually increases, its crystallinity is enhanced and the surface morphology of grain is gradually neatened. Electrochemical test results show that the LiNi _0.5Mn _1.5O ₄ prepared at 800°C has the best cycle reversibility, the highest discharge capacity and the optimal capacity retention.