Supramolecular Assembly of Nanostructured Conducting Polymer Hydrogels by Hydrotropic Agents for Outstanding Supercapacitive Energy Storage

Abstract

Conducting polymer hydrogels (CPHs) are relevant to energy storage due to their micro-nanoscale three-dimensional network combined with a high electronic conductivity and electrochemical activity. The successful implementation of CPHs as an energy storage material requires solving two barriers: (1) low capacitance and electronic conductivity of current CPHs and (2) the lack of simple and scalable chemical synthesis routes. In this work, we propose a different approach for the synthesis of CPHs based on a supramolecular self-assembly induced by hydrotropic agents. The proposed synthesis method induces the formation of networks with superior electronic conductivity which does not require the addition of costly additives. Herein, para-toluene sulfonic acid (p-TSA) was proposed to produce CPHs of polypyrrole (PPy). The method was further extended to other polymer and hydrotropic agents as polyaniline and camphor sulfonic acid, demonstrating the versatility of the synthesis method. It was found that morphology and physical–chemical and electrochemical properties of PPy-CPHs can be fine-tuned with the amount of doping agents. The optimized PPy-CPHs sample possesses a high specific gravimetric capacitance of 560 F g–1 and an areal capacitance of 695 mF cm–2 at 0.75 A g–1 in addition to a capacitance retention of 72% at 10 A g–1, significantly higher than most state of the art PPy electrodes. Characterization suggests that CPH’s faster charge transfer and enhanced ionic and electronic conductivity are due to the higher degree of conjugation, porosity, and size of polymer clusters. Moreover, the symmetric supercapacitor devices with liquid and solid electrolytes exhibit an excellent energy storage performance with a maximum energy density of 13 W h kg–1 and power density of 3.6 kW kg–1. These devices also exhibit a capacitance retention of 82% after 5000 cycles at 5 A g–1.

Corrosion protection of aluminum alloy (AA2219-T6) using sulfonic acid-doped conducting polymer coatings

“…For over 150 years, the diverse chemistry, and fascinating electroactive properties of conducting polymers have been known to the scientific community. 14 Conducting polymers owing to the extensive main-chain p-conjugation radically increase the rigid rod chain stiffness of the polymer backbone, which can be chemically manipulated by the nature and degree of doping and via blending with conventional polymers thus tuning the molecular structure for use in biochemical sensors, [15][16][17] corrosion protection of metals, 18,19 electromagnetic interference shielding, 20 electrostatic discharge protection 21 and a variety of explicit applications. 22 Lately, the application of conductive polymer (CP)-based anticorrosive coatings has received considerable attention.…”

“…Organic acids are preferred due to their good compatibility with resins. In this study, the chelation ability of organic acids [camphor sulphonic acid (CSA), 18 p -toluene sulphonic acid ( p -TSA), 18 and sulfosalicylic acid (SSA)] 39,40 with an aluminum alloy was assessed. The anti-corrosion behavior of doped CPs in an epoxy matrix was also evaluated via EIS.…”

Soft, flexible and self-healable supramolecular conducting polymer-based hydrogel electrodes for flexible supercapacitors

“…To further improve the robustness and the mechanical performance of the conducting polymer-based hydrogel for epidermal bioelectronics, the supramolecular crosslinking strategies between rigid conducting polymers and soft polymers have been investigated. [13][14][15][16][17] Li et al reported a high performance, flexible, solid-state supercapacitor based on the supramolecular assembly of polyaniline (PANI) and polyvinyl alcohol (PVA), made through boronate bonds. 14 The developed supercapacitor exhibited a specific capacitance of 153 F g À1 , with a high energy density of 13.6 W h kg À1 .…”

In Situ Spectroelectrochemical-Conductance Measurements as an Efficient Tool for the Evaluation of Charge Trapping in Conducting Polymers

“…4−6 In particular, in situ UV−vis−NIR spectroelectrochemistry has been widely employed to evaluate the electronic transitions involved in the charging/discharging process of π-conjugated polymers. 7−12 These materials have received increasing attention due to their possible use in sensing, 13−15 energy storage and conversion, 16 and environmental remediation, 17 as well as in bioelectronics, 18,19 and neuromorphic computing. 20 Nevertheless, the type of charge carrier, e.g., σ-dimers, πdimers, polaron pair, and bipolaron, and the mechanisms of charge carrier transport, intrawire and interwire, remains still a point of discussion.…”

“…Among the different spectroscopies coupled with electrochemistry, UV–vis is one of the most used techniques due to the simple correlation between the absorption changes and the simultaneous electrochemical measurements. This technique has been used to study not only single step electron-transfers, but also multistep redox reactions or the formation of mixed-valence intermediates. − In particular, in situ UV–vis–NIR spectroelectrochemistry has been widely employed to evaluate the electronic transitions involved in the charging/discharging process of π-conjugated polymers. − These materials have received increasing attention due to their possible use in sensing, − energy storage and conversion, and environmental remediation, as well as in bioelectronics, , and neuromorphic computing . Nevertheless, the type of charge carrier, e.g ., σ-dimers, π-dimers, polaron pair, and bipolaron, and the mechanisms of charge carrier transport, intrawire and interwire , remains still a point of discussion. , Thus, an important aspect in conducting polymer (CP) research is to develop in situ spectroelectrochemical methods that allow real-time monitoring of the electrochemical, electric, and optical properties of conducting materials.…”