Grain size effects on the dielectric properties of CaCu3Ti4O12 ceramics for supercapacitor applications.

CaCu 3 Ti 4 O 12 ceramic specimens for supercapacitor applications were prepared by the conventional mixed oxide method. The specimens were prepared under different sintering conditions at 1125 °C. The SEM results indicated that the mean grain size of CaCu 3 Ti 4 O 12 increased with increasing sintering time (30 min–12 h). Using SEM analysis, it was observed that at a sintering time of 2 h, CaCu 3 Ti 4 O 12 ceramic specimens had large-sized grains and the agglomerated parts consisted of small-sized grains and grain boundaries. The X-ray diffraction patterns showed single-phase ceramics with a cubic structure. Increasing sintering times led to substantial improvements in permittivity. The different spectra of frequency dependent impedance spectroscopy for large grains and small grains were compared and analyzed using Cole–Cole plots. AC conductivity as a function of the as a function of sintering times of CaCu 3 Ti 4 O 12 ceramics was investigated. [ABSTRACT FROM AUTHOR]