Electrochemical properties of Li[Li0.2Mn0.54Co0.13Ni0.13]O2 cathode thin film by RF sputtering for all-solid-state lithium battery

The Li[Li0.2Mn0.56Ni0.13Co0.13]O2 thin films were prepared by radio frequency magnetron sputtering on Pt/Ti/SiO2/Si substrate with target contained a 5% excess of lithium precursor. Thin films were deposited under various deposition conditions such as working pressure, gas ratio of Ar and O2, and the temperature of in-situ annealing treatment. The thin films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and atomic force microscopy (AFM). The electrochemical property was estimated by a WBC3000 cycler with Li|Li[Li0.2Mn0.54Ni0.13Co0.13]O2 half-type cell at 1C charge/discharge rate. The (0 0 3) and (1 0 4) diffraction peaks which represent layered α-NaFeO2 type structure (space group R-3m) were observed. Optimal magnetron sputtering conditions were detected. The 500 °C annealed thin film after deposited at 10 m Torr in Ar:O2=3:1 shows a high discharge capacity of around 62 μAh/cm2 μm with a high cyclic retention.