Improving of the battery performance of Dy-substituted LiCoO2 and investigating the mechanism of the cells

In this study, we successfully fabricated LiCo1-xDyxO2 (where x = 0.0–0.5) samples and investigated the structural and electrochemical properties. The Dy-substituted LiCoO2 samples were characterized by X-ray diffraction (XRD), X-ray absorption spectroscopy (XAS), Fourier-transform infrared (FTIR), and Raman measurements before and after cycling. The lattice volume and effective magnetic moment were increased by the substitution of the Dy ions in the structure. The capacity fading mechanism of Dy-substituted LiCoO2 via ex situ X-ray diffraction, XAS, Raman and FTIR spectroscopy were investigated. According to the electrochemical performance of the batteries, the x = 0.04 electrode had better cycling properties up to 400 cycles, which are better than that of the pure LiCoO2. We suggested that the critical number of Dy in LiCoO2 facilitates the Li-diffusion by increasing lattice volume. According to the battery performance temperature dependence analysis from 10 to 50 °C, the electrolyte just below degradation temperature shows better cycling since the ions are more mobile in this case.