Relaxation studies of bulk samarium doped ceria electrolyte

Abstract

The nanocrystalline samarium doped ceria powder of phase Ce 0.8 Sm 0.2 O 1.9 was pelletized and sintered at about 1,623 K for the study of relaxation process. The impedance measurements were done within the frequencies from 1 Hz to 1 MHz for wide temperature range of 529-673 K. The temperature-dependent relaxation frequency found to be shifted towards higher frequency region from 17.26 to 707.96 KHz and the corresponding relaxation time for oxygen ions transport was varied from 9.22 to 0.22 μS. The temperature dependent conductivity and relaxation frequency revealed Arrhenius nature, showing activation energies 1.18 and 1.01 eV, respectively. This difference was attributed to pronounced interference due to the grain boundaries. The effect of sintering on microstructure of the sample was studied by using SEM and X-ray diffractometer (XRD). The structural and phase stability study was done by hightemperature (HT)-XRD. The thermal expansion coefficient of the samarium doped ceria powder determined from HT-XRD was found to be 13.9×10 −6 K −1 .

Structure and electrical properties of lithium nickel manganese oxide (LiNi0.5Mn0.5O2) prepared by P123 assisted hydrothermal route

“…The low intense peak in high frequency region was attributed to the grain interior impedance and the one at mid frequency was related to the grain boundary impedance (indicated by arrows in fig. 7) [53]. The real and imaginary components of the impedance were gradually decreasing as the frequency increases which was attributed to the reduction of space charge effect at higher frequencies.…”