Physical and Electrochemical Characterization of LiCo0.8M0.2O2 (M=Ni,Zr) Cathode Films for All-solid-state Rechargeable Thin-film Lithium Batteries

LiCo0.8M0.2O2 (M=Ni,Zr) films were fabricated by radio frequency sputtering deposition combined with conventional annealing methods. The structures of the films were characterized with X-ray diffraction (XRD), Raman spectroscopy and scanning electron microscopy (SEM) techniques. It was shown that the 700 ±C-annealed LiCo0.8M0.2O2 has an @-NaFeO2-like layered structure. All-solid-state thin-film batteries (TFBs) were fabricated with these films as the cathode and their electrochemical performances were evaluated. It was found that doping of electrochemically active Ni and inactive Zr has different effects on the structural and electrochemical properties of the LiCoO2 cathode films. Ni doping increases the discharge capacity of the film while Zr doping improves its cycling stability.