Investigation of the pseudocapacitive properties of polyaniline nanostructures obtained from scalable chemical oxidative synthesis routes

In this study, polyaniline (PANi) nanostructures synthesized through a vast majority of straightforward chemical oxidative methods to compare capacitance and rate capability of the products obtained using inexpensive, scalable, and well-established procedures. Effects of deployed method and conditions are assessed on the chemical and pseudocapacitance properties of PANI in aqueous electrolyte. There was a correlation between morphology and electrochemical performance of the samples and a relatively high specific capacity (901Fg(-1) at 10mVs(-1)) observed for nanofibrous PANi synthesized by interfacial polymerization at room temperature. Ultrasonic assisted polymerization studies showed that higher temperature and irradiation times convert morphology from nanorod to granule and decrease doping degree. However, by deploying HCl as dopant, electrochemical results were comparable with other methods. For instance, lowest charge transfer resistance value (smallest semicircle) and a relatively high capacitance (704Fg(-1) at 10mVs(-1)) were determined for PANi sample synthesized via ultrasonic assisted polymerization. On the other hand, p-toluenesulfonic acid was a better dopant for PANi synthesized via rapidly mixed reaction. It was shown that three-like nanostructures with high capacitance are obtainable via a template-free rapidly mixed reaction. Results showed that a specific condition and dopant are optimal for each synthetic route and it is possible to obtain PANi with adequate electrochemical performances and morphology in short reaction times even at room temperature, which is very interesting from the industrial point of view.