Enhanced ionic conduction of CdI2Ag2CrO4 and Al2O3 composite solid electrolytes

•A series of Al2O3 doped CdI2Ag2CrO4 composite solid electrolytes was prepared and characterized by XRD, DTA and AC impedance spectroscopy.•AgI component is formed due to an ion exchange reaction by following the Pearson’s acid base theory.•The conductivity increased with increase of the dispersoid (Al2O3) content and displayed maximum conductivity value (σ = 2.49 × 10−5 S cm−1 at 30 °C) for x = 0.3 composition.

A series of Al2O3 doped CdI2Ag2CrO4 composite solid electrolytes was prepared and studied by various techniques. XRD pattern and DTA curve show the presence of AgI component formed due to an ion exchange reaction by following the Pearson’s acid base theory. The peaks of XRD and DTA curve became broad after the composite formation. SEM images clarified the presence of multiphase composite. A.C. impedance spectroscopy shows the single semicircle at lower frequency attributed to dominant nature of grain boundary over the grain. The Arrhenius plots of the conductance show a sharp jump at 150 °C due to β → α phase transition and it decreases with increase of Al2O3 content due to partial amorphization of the salt. The conductivity of the composite increases with increase of dispersoid (Al2O3) and displayed maximum value (σ = 2.49 × 10−5 S cm−1 at 30 °C) for x = 0.3. The value of dielectric constant was increased by increasing temperature owing to increase in mobility and activity of charge carriers, while it shows the decreasing order with respect to frequency.

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