An overview on the recent developments in polyaniline‐based supercapacitors

Abstract

With the ever-increasing depletion of nonrenewable fossil fuel reserve, greater attention has been directed towards renewable energy storage devices. One of the most important of such devices is the supercapacitor, which exhibits high specific capacitance. Polyaniline (PAni) is a versatile conducting polymer, which has demonstrated excellent electrochemical properties along with good stability and ease of synthesis.Therefore, PAni has been extensively used in the fabrication of supercapacitors. In the last few decades, researchers have studied the effect of morphology, developed during the synthesis of PAni, on its electrochemical properties. It is known that the electrical conductivity and the electrochemical properties of PAni get influenced by the level and type of dopant used, the method of synthesis adopted, and the surface area and porosity possessed. However, it has been realized that supercapacitors based on PAni suffer from short cycle life. This led to development of PAni composites with carbon-based materials and transition metal oxides. In this review, focus has been laid on the achieved performance levels of the recently developed PAni-based supercapacitors. In addition, an attempt has been made to study the fundamental aspects of the conductivity and the electrochemical properties of PAni and their effect on the supercapacitor performance. Moreover, several new interesting applications of PAni-based supercapacitors have also been included in this review.1 | INTRODUCTION Supercapacitors, for the last few decades, have accrued immense attention from the scientific society for their unique properties like long cycle life, wide operating temperature window, high power density, and fast charge-discharge cycle. 1,2 It can store charge in two different ways-either by electrostatic way (electrical double layer capacitors, EDLCs) or by thorough fast and reversible Faradaic reaction (pseudocapacitors). In case of EDLCs, the opposite charges are stored on the surface of the two parallel conductive plates with electrolytes between them that help in shuttling of ions between the two.EDLCs type of supercapacitors have shown higher power densities and hence higher rate capabilities. It has been studied that carbon-based materials have shown EDLC-type behavior with high power density, low cost, and tunable porosity but lacks in energy density. [3][4][5] Pseudocapacitors store charges through fast and reversible reaction, which can store charges near the surface of the electrode, and thus possess high capacitance but low power density. Transition metal oxides (TMOs), mixed TMOs, 6 and conducting polymers (CPs) exhibit pseudocapacitance. TMOs exhibit multiple oxidation states with low activation energy but lack high capacitance and flexibility and suffer from instability. In recent years, extensive studies have been done on TMOs and carbon-based materials. Another group of fascinating materials is CPs, which show high specific capacitance, flexibility, and ease of fabrication. The performance of the supercapacitor is...

The effect of polyaniline electrode doped with transition metal ions for supercapacitors

“…To further improve the capacitive performance of supercapacitor, a variety of electrode materials have been studied in PsCs. In this one, developing the conductive polymer composite electrode is one of the feasible path to enhance the specific capacitance of this kind of electrode 19 . And this, the introduction of the different transition metal ions into the conductive polymer is one of the efficient ways to improve the capacitance, in which the reversible pseudocapacitive reactions can enhance the electrical conductivity 20 .…”

The First Stages of Chemical and Electrochemical Aniline Oxidation—Spectroscopic Comparative Study

“…Polyaniline (PANI) is one of the most studied conducting polymers. It has a wide range of applications, including wastewater processing [1,2], catalysis [2], sensing [3][4][5][6], biomedical [5,7,8], optical [9] and electrochemical [9][10][11][12][13] applications. Many of these areas require PANI in the form of a thin film.…”

Melt‐mixed carbon nanotubes/polymer nanocomposites

“…Finally, it is important to discuss the practical application of these polymer/CNTs composites. Broadly, it finds application in electronics, biomedicals, sensor, organic light‐emitting diodes, and in energy storage devices . The main applications of polymer/CNTs composites are electromagnetic interference (EMI) shielding, Li‐ion batteries, and electrostatic dissipation (ED) that requires high conductivity.…”

“…Broadly, it finds application in electronics, biomedicals, sensor, organic light-emitting diodes, and in energy storage devices. [121,122] The main applications of polymer/CNTs composites are electromagnetic interference (EMI) shielding, [123,124] Li-ion batteries, [125] and electrostatic dissipation (ED) that requires high conductivity. Materials with higher conductivities are more suitable for EMI application, while materials with lower conductivities are preferred for ED application.…”