Synthesis of lithium nickel cobalt manganese oxide Nano powder by ultrasonic spray pyrolysis as cathode active material of lithium ion battery

Nowadays, lithium ion batteries (LIBs) have special situation in portable electronics market and widespread researches have carried out in a various fields of LIBs such as cost reduction, preventing environmental damages, and improving performance. The main components of a LIB are anode, cathode, electrolyte and separator, among which the cathode material is a limiting factor in terms of both cost and performance [1]. The first cathode material for commercial LIB was lithium cobalt oxide (LCO) which has problems like cobalt resource constraints, high cost, toxicity, and low safety, and these problems has limited use of LCO in high power batteries of electric and hybrid electric vehicles [2]. Therefore researchers are looking for alternatives, for which their LiNixCoyMn1-x-yO2 (NCM) compositions are one of the candidates owing to have higher capacity, lower cost and better thermal stability than LCO [3]. This work focused on synthesis of lithium nickel cobalt manganese oxide using ultrasonic spray pyrolysis. This method produces high purity material, easily control properties of product, and have low cost compared to other conventional synthesis methods including solid state, sol-gel and co-precipitation [4]. The effect of concentration of precursor solution on morphology and particle size, effect of synthesis temperature and calcination temperature on morphology, structure, and capacity were investigated. Crystal structure of LiNi0.4Co0.2Mn0.4O2 powder was studied by X-ray diffraction (XRD), and all patterns indicated ordered layered structure. Scanning electron microscopic (SEM) images showed micron-sized spherical particles composed of nanoparticles. Initial charge capacity of LiNi0.4Co0.2Mn0.4O2 as cathode material in voltage range of 2.5-4.4V reached to124 mAh/g, for the sample synthesized in 600ºC and calcinated in 850ºC. The coulombic efficiency and capacity retention after 10 charge-discharge cycles were 90% and 80% respectively.