Crystalline phase dependence of the electrochemical properties of chitosan/polyaniline/TiO2-KI/I2 quasi solid polymer electrolyte

The effect of titanium dioxide nanoparticles (TiO2 NPs) crystalline phases on the electrochemical properties of chitosan/polyaniline/TiO2-KI/I2 quasi solid electrolyte has been systematically studied. We synthesized the TiO2 nanoparticles in various crystalline phases as nanofiller in chitosan-based polymer electrolyte, then investigated the effect of the different TiO2 crystals on the electrochemical properties of the electrolyte. An amorphous TiO2 nanoparticle is used for comparison with the resulting TiO2 NPs prepared in various calcination temperatures that form a set of TiO2 NPs in various crystalline phases (anatase-, brookite-, or rutile- dominated phase). The synthesized products were characterized using FT-IR, XRD, TEM, and SEM, while their optical and electrochemical properties were respectively analyzed using DR-UV and cyclic voltammetry method. We found that the presence of TiO2 NPs in a chitosan-based polymer electrolyte as a nanofiller provides an additional pathway of the I−/I3− redox cycle, increasing the anodic and cathodic peak current intensity, with the combination of anatase and brookite (A + B) TiO2 (calcined at 400 °C) exhibited the highest performance. The reversibility of the redox cycle was even improved with the addition of polyaniline, offering a promising natural polymer-based solid and quasi solid electrolyte system