Three-Dimensional Mesoporous Polyindole Architectures for Supercapacitor Applications

Abstract

Recently, polyindole (PIN) has quickly started to gain research interest in the field of energy storage applications. Here, we developed a three-dimensional (3D) PIN gel for the first time without using either additives or cross-linkers to explore its efficacy as a supercapacitor. The PIN aerogel obtained by freeze-drying the 3D PIN gel exhibits a larger surface area, enhanced electronic conductivity, and appropriate mechanical properties compared to conventionally synthesized PIN powder. The PIN aerogel is also capable of delivering an improved capacitance of 168 F g–1 at a current density of 0.5 A g–1. Further, we have also demonstrated that PIN can be used as a cross-linking agent in the development of a PIN/graphene hydrogel (PG hydrogel). The PG hydrogel was freeze-dried to obtain PIN/graphene aerogels (PG aerogels). With improved surface areas and 3D porous nanostructures, the PG aerogels demonstrated their potential as high-performance supercapacitor electrodes with a high specific capacitance of ∼399 F g–1 at 0.5 A g–1, better rate capability, and long-term cyclic stability (∼92% capacitance retention after 2000 cycles) in a three-electrode system. Besides, we also report the fabrication of a PG aerogel∥PG aerogel symmetric supercapacitor (SSC) of a two-electrode configuration, which manifests a favorable C sp of 63 F g–1 at 0.5 A g–1 and retains a stability of 99.8% even after 2000 cycles. This SSC device shows a significant energy density of 28.35 Wh kg–1 at a power density of 497.85 W kg–1. The self-aggregation of PIN and the interaction of PIN with graphene was assessed using molecular dynamics (MD) simulations. The MD simulation results were found to be in good agreement with the experimental observations. Overall, our findings evidence that PIN can form 3D architectures in virgin nature and composite with graphene and thus has important implications for future material design of PIN-based electrochemical energy storage devices.

Mescoporous Nickel Titanate–Titanium Oxide Complex Material for Enhanced Energy Storage Application

“…It requires more reliable power sources that compromise high energy density and more extended durability − also to decrease already overburdened fossil fuels’ resources. Nowadays, solar cells, multifunctional electrochromic devices, − batteries, and supercapacitors − are proving their ability to store charge/energy for electronic gadgets. Supercapacitors have become one of the most promising energy storage devices, as they have high energy density, high power density, fast charging–discharging, and long cyclic stability. , This has attracted more attention due to their application in green vehicles, the need of the hour to meet global challenges.…”

Hydrotrope-assisted interconnected mesoporous polyindole-decorated carbon nanotubes: synthesis, characterisation, and fabrication of asymmetric supercapacitor

“…1 Among these, owing to the better electrochemical response, a greater focus has been on using ESD in supercapacitors. 10,12,13 Supercapacitors are ESD that primarily store and release energy via a redox action between two electrostatically charged layers in the presence of an electrolyte, which are divided using an insulating separator. 14 The redox action is an effect of moving ions between the electrolyte and electrode material at the interface.…”

“…15 These challenges include pre and post-processing complications that chiefly arise owing to the initial selection of electrolyte or solvents compatible with indole. 16 Previously, several solvents or electrolytes have been preferred for polymerisation of indole by the scientific community, such as for chemical oxidation (chloroform, 17,18 methanol, 19 acetone, 20 ethanol 12 ), electrospinning (acetonitrile 21 ), emulsification (hydrochloric acid 22 with surfactant assistance 5 by cetyl trimethyl ammonium bromide (CTAB), sodium dodecyl sulphate (SDS), Tween 80 (TW80), or FeCl 3 ), electrochemical (acetonitrile 23 ) interfacial polymerisation (dichloromethane, 24 surfactant-assisted 25 ).…”

Fabrication of ternary polyaniline‐titanium dioxide‐polypyrrole (PANI‐TiO2‐PPy) nanocomposite as an efficient polymer electrode for supercapacitors

“…More recently, researchers are focusing on various combinations of pseudocapacitive materials (conducting polymers and transition metal oxides) to ensure their possible use as efficient electrode materials that can drastically improve the device's energy density along with power density. 5 Many conducting polymer based active electrode materials, namely polyaniline (PANI), 6 polythiophene (PTh), 7 polypyrrole (PPy), 8 polyindole (PIN), 9 poly(o-phenylenediamine) (PoPD), 10 poly(naphthylamine) (PNA), 11 polycarbazole (PCz), 12 polyanisidine (PANIS), 13 poly (3,4-ethylenedioxythiophene) (PEDOT), 14 poly(para-phenylene) (PPP), 15 poly(phenylenevinylene) (PPV), 16 polyfuran (PF), 17 poly(acetylene) (PAC), 18 poly(p-phenylene sulfide) (PPS), 19 and poly(p-phenylene vinylene) (PPV) 20 have been explored in the past. Among the mentioned conducting polymers, PANI and PPy based electrode materials have received much attention in high-performance supercapacitors as they possess distinctive characteristics such as good intrinsic conductivity, increased electrochemical activity and high energy density.…”