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Solid electrolytes are the principal component of solid oxide fuel cells (SOFCs) and play a vital role in controlling the conduction mechanism. We have prepared multiple compositions of Sr3 − 3xK3xSi3O9 (0.0 ≤ x ≤ 0.2) via solid-state reaction route for the possible application as solid electrolyte for SOFCs. We have studied the phase formation and phase evolution via XRD, Raman and FTIR; morphological transformation via SEM and EDX and the ion-conducting behaviour of the system via conductivity measurements with varying the potassium concentration. Band gap of the investigated compositions was determined via the Tauc plot of UV-Vis measurement. A correlation between the dopant concentration, phase formation and conductivity has been established to explain the conductivity behaviour. The results indicate that high K concentration is helpful in achieving the required transport behaviour as required for IT-SOFC electrolytes. [ABSTRACT FROM AUTHOR]

The influence of calcium doping on the Y3GaO6 system was systematically investigated for electrochemical applications. The Y3(1−x)Ca3xGaO6 (x = 0, 0.02, 0.04, 0.08, 0.12) ceramics compositions were prepared via conventional solid-state reaction route and their structural, electrical and electrochemical properties were investigated. The structural phase analysis revealed the formation of the orthorhombic phase with the Cmc21 space group. However, at higher concentrations of calcium doping, i.e. x > 0.02, a few secondary phases of Y2O3 and CaCO3 were also observed. Impedance spectra suggest an increase in the total conductivity up to x = 0.02 of Ca doping, and a decrease in the conductivity was observed for the higher concentration of Ca substitution. The substitution of Ca with x > 0.02 not only increases the oxygen vacancies rather segregates the impurities along the grain boundaries. Consequently, the impurities have negative influence on both the grain and grain-boundary conductivities. Cyclic voltammetry and Chronoamperometry studies have also been performed to characterize the samples. [ABSTRACT FROM AUTHOR]