A review of π-conjugated polymer-based nanocomposites for metal-ion batteries and supercapacitors

Developments in conducting polymer-, metal oxide-, and carbon nanotube-based composite electrode materials for supercapacitors: a review

Supercapacitors are the latest development in the field of energy storage devices (ESDs). A lot of research has been done in the last few decades to increase the performance of supercapacitors. The electrodes of supercapacitors are modified by composite materials based on conducting polymers, metal oxide nanoparticles, metal-organic frameworks, covalent organic frameworks, MXenes, chalcogenides, carbon nanotubes (CNTs), etc. In comparison to rechargeable batteries, supercapacitors have advantages such as quick charging and high power density. This review is focused on the progress in the development of electrode materials for supercapacitors using composite materials based on conducting polymers, graphene, metal oxide nanoparticles/nanofibres, and CNTs. Moreover, we investigated different types of ESDs as well as their electrochemical energy storage mechanisms and kinetic aspects. We have also discussed the classification of different types of SCs; advantages and drawbacks of SCs and other ESDs; and the use of nanofibres, carbon, CNTs, graphene, metal oxide-nanofibres, and conducting polymers as electrode materials for SCs. Furthermore, modifications in the development of different types of SCs such as pseudo-capacitors, hybrid capacitors, and electrical double-layer capacitors are discussed in detail; both electrolyte-based and electrolyte-free supercapacitors are taken into consideration. This review will help in designing and fabricating high-performance supercapacitors with high energy density and power output, which will act as an alternative to Li-ion batteries in the future.

Innovative polymer engineering for the investigation of electrochemical properties and biosensing ability

Subtle engineering for the generation of a biosensor from a conjugated polymer with the inclusion of fluorine-substituted benzothiadiazole and indole moieties is reported. The engineering includes the electrochemical copolymerization of the indole-6-carboxylic acid (M1) and 5-fluoro-4,7-bis(4-hexylthiophen-2-yl)benzo[c][1,2,5]thiadiazole (M2) on the indium tin oxide and graphite electrode surfaces for the investigation of both their electrochemical properties and biosensing abilities with their copolymer counterparts. The intermediates and final conjugated polymers, Poly(M1) [P-In6C], Poly(M2) [P-FBTz], and copoly(M1 and M2) [P-In6CFBTz], were entirely characterized by 1H NMR, 13C NMR, CV, UV-Vis-NIR spectrophotometry, and SEM techniques. HOMO energy levels of electrochemically obtained polymers were calculated from the oxidation onsets in anodic scans as -4.78 eV, -5.23 eV, and -4.89 eV, and optical bandgap (Egop) values were calculated from the onset of the lowest-energy π-π* transitions as 2.26 eV, 1.43 eV, and 1.59 eV for P-In6C, P-FBTz, and P-In6CFBTz, respectively. By incorporation of fluorine-substituted benzothiadiazole (M2) into the polymer backbone by electrochemical copolymerization, the poor electrochemical properties of P-In6C were remarkably improved. The polymer P-In6CFBTz demonstrated striking electrochemical properties such as a lower optical band gap, red-shifted absorption, multielectrochromic behavior, a lower switching time, and higher optical contrast. Overall, the newly developed copolymer, which combined the features of each monomer, showed superior electrochemical properties and was tested as a glucose-sensing framework, offering a low detection limit (0.011 mM) and a wide linear range (0.05-0.75 mM) with high sensitivity (44.056 μA mM-1 cm-2).

Intrinsically Conducting Polymer Composites as Active Masses in Supercapacitors

Intrinsically conducting polymers ICPs can be combined with further electrochemically active materials into composites for use as active masses in supercapacitor electrodes. Typical examples are inspected with particular attention to the various roles played by the constituents of the composites and to conceivable synergistic effects. Stability of composite electrode materials, as an essential property for practical application, is addressed, taking into account the observed causes and effects of materials degradation.

Fabrication of Textile-Based Flexible Supercapacitor with a Textile Dye on Polyaniline-Based Composite Electrode for Enhanced Energy Storage

Polyaniline (PANI) is a promising conductive polymer for use in energy storage applications. Here, a one-step hydrothermal method of PANI polymerization on carbon felt electrode was synthesized using an azo dye, a bisulfonated dichloro anionic dye molecule to enhance an efficient textile-based flexible supercapacitor electrode material for energy storage applications. The electrode material synthesized at concentration of 2 mM AY17 exhibits 814.1 F g-1 at the scan rate of 5 mV s-1 with multiwall carbon nanotubes (MWCNTs). Due to electrostatic interaction with the polymer, the presence of high electronegativity Cl atoms in the dye molecule significantly improves the PANI structure's electron donor/acceptor properties. A symmetric supercapacitor exhibits an energy density of 11.7 W h kg−1 at a power density of 300 W kg−1, and it is 4.5 W h kg−1 at 1800 W kg−1 in 3.0 M KCl aqueous electrolyte. The capacitance retention performance value of the symmetric supercapacitor exhibited 81.76% after 2500 cycles.

Electrochemical biosensor based on three components random conjugated polymer with fullerene (C60)

Herein, a conjugated polymer and fullerene bearing architecture-based electrochemical Tyrosinase (Tyr) enzyme inhibition biosensor for indomethacin (INDO) drug active compound has been developed. For this purpose, three moieties of benzoxadiazole, thienopyrroledione, and benzodithiophene containing conjugated polymer; poly[BDT-alt-(TP;BO)] was used as a transducer modifier together with fullerene for catechol detection. The specific combination of these materials is considered an effective way to fabricate highly sensitive and fast response catechol biosensors for the first time. Electrochemical and surface characteristics of the modified electrodes were obtained by cyclic voltammetry, electrochemical impedance spectroscopy, scanning electron microscopy, and atomic force microscopy. The effect of the parameters during chronoamperometric measurements on the biosensor response was also studied. Using optimized conditions, biosensing of catechol was achieved between 0.5 and 62.5 µM with a limit of the detection 0.11 µM. Tyr inhibition was followed with INDO drug active compound and it was found that INDO has a mixed type characteristic of enzyme kinetics with an I₅₀ value of 15.11 µM.