Layered LiNi1−yCoyO2 compounds synthesized by a glycine-assisted combustion method for lithium batteries

The lithiated nickel-cobalt oxide cathode materials were prepared at low temperature using the aqueous glycine-nitrate combustion method. Physicochemical and electrochemical properties of LiNi1−yCo y O2 (0.3 ≤ y ≤ 0.7) calcined at 400–600°C were extensively investigated. It has been found that powders of submicron-sized particles with a layered structure (RR\(\bar 3\)m space group) were obtained at temperatures below 400°C by the acidification reaction of the aqueous nitrate solution. The method involves the mixing of nitrates of Li, Ni and Co, with a combustion agent, glycine in an aqueous medium. Glycine functioned such as a fuel, decomposed the homogeneous precipitate of metal complexes at low temperature, and yielded the free impurity LiNi1−yCo y O2 compounds. The synthesized products were characterized by structural (XRD, SEM), spectroscopic (FTIR) and thermal (DTA/TG) analyses. The electrochemical properties of the synthesized products in rechargeable Li cells were evaluated using a non-aqueous organic electrolyte mixture of 1M LiPF6 in EC + DMC. The electrodes fired at low temperature exhibed a good cycling behavior.