A new gel route to synthesize LiCoO2 for lithium-ion batteries

A new synthetic route, i.e. the radiated polymer gel (RPG) method, has been developed and demonstrated for the production of LiCoO2 powders. The process involved two processes: (1) obtaining a gel by polymerizing a mixed solution of an acrylic monomer and an aqueous solution of lithium and cobalt salts under γ-ray irradiation conditions and (2) obtaining LiCoO2 powders by drying and calcining the gel. Thermogravimetric analysis (TGA), X-ray diffraction (XRD) and electron scanning microscopy (SEM) were employed to study the reaction process and the structures of the powders. Galvanostatic cell cycling, cyclic voltammetry and ac impedance spectroscopy were used to evaluate the electrochemical properties of the LiCoO2 powders. It was found that a pure phase of LiCoO2 can be obtained at the calcination temperature of 800 °C. Both the particle size (micrometer range) and specific charge/discharge capacity of an RPG-LiCoO2 powder increase with increasing the concentration of its precursor solution.