Electrochemical impedance spectroscopic analysis of aluminum and gallium mixed matrix membranes

Mixed matrix membrane revolutionized the field of electrochemistry with its multiple applications as a solid electrolyte, actuator, sensor, and storage device, because of its better processability, flexibility, and light-weight. The present study is designed to investigate the role of hybrid filler in the electrochemical properties of the mixed matrix membrane. For this purpose, aluminum and gallium hybrids with indole and its derivatives were synthesized using the post-modification method. Then, synthesized hybrids were dispersed evenly into the polysulfone matrix and developed its membrane using the immersion precipitation phase inversion method. The FTIR result of aluminum and gallium hybrids identified the absorption bands of −C=C (1485–1400 cm −1 ), −CN (1340–1122 cm −1 ), and –NH (1625–1535 cm −1 ) with repeating units of Al–O (1178 cm −1 ) and Ga-O (1132–1117 cm −1 ). SEM images showed the spherical-shaped aluminum oxide and rod-shaped gallium oxide. XRD pattern corresponded to the cubic and trigonal crystal system of aluminum and gallium oxides. Electrochemical impedance study showed significant improvement in the electrical behavior of aluminum and gallium mixed matrix membranes where aluminum and gallium hybrids as a filler create the continuous network for the easy transportation of the charge carriers. The existence of the peaks at a similar position in both impedance and modulus formalisms suggests relaxations of the same type of charge species at the same type of electroactive region and disclose the real picture of the material.