Search Results (82)

Electrodes and electrolytes are critical components for the performance of supercapacitors. In this study, supercapacitors with different interfaces were assembled using polypyrrole (PPy) or a polypyrrole–carbon nanotube (PPy-CNT) composite as active materials, and dimethyl sulfoxide (DMSO) and sodium chloride (NaCl) were used as electrolytes. Electrochemical measurements were obtained by cyclic voltammetry (CV) at a scan rate of 20 mV/s and galvanostatic charge–discharge (GCD) measurements at a scan rate of 50 µA/s. The results suggest that the supercapacitor with a PPy-CNT composite and NaCl electrolyte has promising electrochemical characteristics. Full article

Polybenzoxazine (PBz)-based conducting materials have gained significant attention due to their unique combination of thermal stability, mechanical strength, and electrical conductivity. These polymers integrate the inherent advantages of polybenzoxazines—such as low water absorption, high glass transition temperature, and excellent chemical resistance—with the electrical properties of conducting polymers like polyaniline, polypyrrole, and polythiophene. The incorporation of conductive elements in polybenzoxazine networks can be achieved through blending, in situ polymerization, or hybridization with nanostructures such as graphene, carbon nanotubes, or metallic nanoparticles. These modifications enhance their charge transport properties, making them suitable for applications in flexible electronics, energy storage devices, sensors, and electromagnetic shielding materials. Furthermore, studies highlight that polybenzoxazine matrices can improve the processability and environmental stability of conventional conducting polymers while maintaining high conductivity. The structure–property relationships of polybenzoxazine-based composites demonstrate that tailoring monomer composition and polymerization conditions can significantly influence their conductivity, thermal stability, and mechanical properties. This review summarizes recent advancements in PBz composites, focusing on their synthesis, structural modifications, conductivity mechanisms, and potential applications in advanced energy storage systems. Full article

Organic hybrid materials are gaining traction as electrode candidates for energy storage due to their structural tunability and environmental compatibility. This study investigates polyimide/carbon nanotube/polypyrrole (PI/CNTs/PPy) hybrid nanocomposites, focusing on the correlation between thermal imidization temperature, polypyrrole deposition time, and the resulting electrochemical properties. By modulating PI processing temperatures (90 °C, 180 °C, 250 °C) and PPy deposition durations (60–700 s), this research uncovers critical structure–function relationships governing charge storage behavior. Scanning electron microscopy and electrochemical impedance spectroscopy reveal that low-temperature imidization preserves porosity and enables ion-accessible pathways, while moderate PPy deposition enhances electrical conductivity without blocking pore networks. The optimized composite, processed at 90 °C with 60 s PPy deposition, demonstrates superior specific capacitance (850 F/g), high redox contribution (~70% of total charge), low charge transfer resistance, and enhanced energy/power density. In contrast, high-temperature processing and prolonged PPy deposition result in structural densification, increased resistance, and diminished performance. These findings highlight a synergistic design approach that leverages partial imidization and controlled doping to balance ionic diffusion, electron transport, and redox activity. The results provide a framework for developing scalable, high-performance, and sustainable electrode materials for next-generation lithium-ion batteries and supercapacitors. Full article

This paper discusses the results of our investigation of the effect of processing parameters on the electrochemical properties of poly(vinylidene fluoride) single-walled carbon nanotube sheets and PVDF-CNTs modified by solution cast polyimide coating, followed by electrodeposition of polypyrrole. The polyimide-coated single-wall carbon nanotube sheet–PI/SWCNTs composite consists of SWCNT and PVDF (9:1) wt.% and 0.1–1 wt.% polyimide. The processing temperature varied from 90 to 250 °C. SEM images validated the nanostructure, while EDX confirmed the material composition. EIS analysis showed that the composite electrode material processed at 90 °C and followed by electrodeposition of polypyrrole has the lowest bulk resistance (65.27 Ω), higher porosity (4.59%), and the highest specific capacitance (209.16 F/g), indicating superior ion transport and charge storage. Cyclic voltammetry and cyclic charge–discharge analyses revealed that the hybrid composite electrode processed at 90 °C achieved a specific capacitance of 655.34 F/g at a scan rate of 5 mV/s, demonstrating excellent cycling stability over 10 cycles at a current density of 0.5 A/g. In contrast, composite electrodes processed at 180 °C and 250 °C showed decreased performance due in part to structural densification and low porosity. These findings underscore the critical role of processing temperatures in optimizing the electrochemical properties of PI/SWCNT composites, advancing their potential for next-generation energy storage systems. Full article

Tungsten microparticles were coated with globular or nanotubular polypyrrole in situ during the oxidation of pyrrole in aqueous medium with ammonium peroxydisulfate or iron(III) chloride, respectively. The resulting core–shell composites with various contents of tungsten were obtained as powders composed of metal particles embedded in a semiconducting polymer matrix. The coating of tungsten with polypyrrole was analysed by FTIR and Raman spectroscopies. The resistivity of composite powders was determined by the four-point van der Pauw method as a function of pressure applied up to 10 MPa. The degree of compression was also recorded and its relation to electrical properties is discussed on the basis of the percolation concept. The electrical properties of composites are afforded by polypyrrole matrix and they are independent of tungsten content. As the conducting tungsten particles are separated by polypyrrole shells, they cannot produce conducting pathways and behave similarly as a nonconducting filler. Full article

Core–shell inorganic/organic composites have often been applied as fillers in electromagnetic interference shielding. Those composed of conducting polymers and ferrites are of particular interests with respect to their electrical and magnetic properties. Pyrrole was oxidized in aqueous medium in the presence of manganese-zinc ferrite microparticles with ammonium peroxydisulfate or iron(III) chloride to yield polypyrrole-coated, core–shell microstructures. The effect of methyl orange dye on the conversion of globular polypyrrole to nanotubes has been demonstrated by electron microscopy when iron(III) chloride was used as an oxidant. The formation of polypyrrole was proved by FTIR spectroscopy. The completeness of ferrite coating was confirmed by Raman spectroscopy. The resistivity of composite powders was determined by four-point van der Pauw method as a function of pressure applied up to 10 MPa. The conductivity of composite powders was determined by a polypyrrole matrix and only moderately decreased with increasing content of ferrite. The highest conductivity of composites, 13–25 S cm⁻¹, was achieved after the deposition of polypyrrole nanotubes. Magnetic properties of composites have not been affected by the polypyrrole moiety, and the magnetization of composites was proportional to the ferrite content. Full article

The development of ISE-based sensors for the analysis of nitrates in liquid phase is described in this work. Focusing on the tetradodecylammonium nitrate (TDDAN) ion exchanger as well as on fluoropolysiloxane (FPSX) polymer-based layers, electrodeposited matrixes containing double-walled carbon nanotubes (DWCNTs), embedded in either polyethylenedioxythiophene (PEDOT) or polypyrrole (PPy) polymers, ensured improved ion-to-electron transducing layers for NO₃⁻ detection. Thus, FPSX-based pNO₃-ElecCell microsensors exhibited good detection properties (sensitivity up to 55 mV/pX for NO₃ values ranging from 1 to 5) and acceptable selectivity in the presence of the main interferent anions (Cl⁻, HCO₃⁻, and SO₄²⁻). Focusing on the temporal drift bottleneck, mixed results were obtained. On the one hand, relatively stable measurements and low temporal drifts (~1.5 mV/day) were evidenced on several days. On the other hand, the pNO₃ sensor properties were degraded in the long term, being finally characterized by high response times, low detection sensitivities, and important measurement instabilities. These phenomena were related to the formation of some thin water-based layers at the polymer–metal interface, as well as the physicochemical properties of the TDDAN ion exchanger in the FPSX matrix. However, the improvements obtained thanks to DWCNT-based ion-to-electron transducing layers pave the way for the long-term analysis of NO₃⁻ ions in real water-based solutions. Full article

New materials and the interactions between them are the basis of novel energy storage devices such as supercapacitors and batteries. In recent years, because of the increasing demand for electricity as an energy source, the development of new energy storage materials is among the most actively studied topics. Conductive polymers (CPs), because of their intrinsic electrochemical activity and electrical conductivity, have also been intensively explored. While most of the high capacitance reported in the literature comes from hybrid materials, for example, conductive polymers composed of metal oxides and carbon materials, such as graphene and carbon nanotubes, new chemistry and the 3D structure of conductive polymers remain critical. This comprehensive review focuses on the basic properties of three popular conductive polymers and their composites with carbon materials and metal oxides that have been actively explored as energy storage materials, i.e., polypyrrole (PPy), polyaniline (PANi), and polythiophene (PTh), and various types of electrolytes, including aqueous, organic, quasi-solid, and self-healing electrolytes. Important experimental parameters affecting material property and morphology are also discussed. Electrochemical and analytical techniques frequently employed in material and supercapacitor research are presented. In particular, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) are discussed in detail, including how to extract data from spectra to calculate key parameters. Pros and cons of CP-based supercapacitors are discussed together with their potential applications. Full article

This study investigates the properties of solution-processed hybrid polyimide (PI) nanocomposites containing a variety of nanofillers, including polyaniline copolymer-modified clay (PNEA), nanographene sheets (NGSs), and carbon nanotube sheets (CNT-PVDFs). Through a series of experiments, the flow behavior of poly(amic acid) (PAA) solution and PAA suspension containing polyaniline copolymer-modified clay (PNEA) is determined as a function of the shear rate, processing temperature, and polymerization time. It is shown that the neat PAA solution exhibits a complex rheological behavior ranging from shear thickening to Newtonian behavior with increasing shear rate and testing temperature. The presence of modified clay in PAA solution significantly reduced the viscosity of PAA. Differential scanning calorimetry (DSC) analysis showed that polyimide–nanographene sheet (PI NGS) nanocomposites processed at a high spindle speed (100 rpm) have lower total heat of decomposition, which is indicative of improved fire retardancy. The effect of processing temperature on the specific capacitance of a polyimide–CNT-PVDF composite containing electrodeposited polypyrrole is determined using cyclic voltammetry (CV). It is shown that the hybrid composite working electrode material processed at 90 °C produces a remarkably higher overall stored charge when compared to the composite electrode material processed at 250 °C. Consequently, the specific capacitance obtained at a scan rate of 5 mV/s for the hybrid nanocomposite processed at 90 °C is around 858 F/g after one cycle, which is about 6.3 times higher than the specific capacitance of 136 F/g produced by the hybrid nanocomposite processed at 250 °C. These findings show that the properties of the hybrid nanocomposites are remarkably influenced by the processing conditions and highlight the need for process optimization. Full article

An all-integrated on-chip electrochemical microcell (10 × 11 mm²) is developed using silicon technology. The potentiometric nitrate ion detection is based on the functionalization of the working microelectrode array with a polymer membrane in fluoropolysiloxane (FPSX) containing ionophore tetradodecylammoniumnitrate (TDDAN) and ionic additive potassium tetrakis[3,5-bis(trifuoromethyl)phenyl]borate (KTFPB) to form an all-solid-state ion selective electrode (ISE). The addition of an ion-to-electron transducing layer between the platinum working electrode and the polymer membrane helped to improve the sensor performances, especially the response time, the sensitivity, and the stability. Composites formed with two conductive polymers were compared: Polyethylenedioxythiophène (PEDOT) and Polypyrrole (PPy), doped with Poly(styrene sulfonate) or double-walled carbon nanotubes (DWCNTs). Full article

This study aims to develop a microelectrode array-based neural probe that can record dopamine activity with high stability and sensitivity. To mimic the high stability of the gold standard method (carbon fiber electrodes), the microfabricated platinum microelectrode is coated with carbon-based nanomaterials. Carboxyl-functionalized multi-walled carbon nanotubes (COOH-MWCNTs) and carbon quantum dots (CQDs) were selected for this purpose, while a conductive polymer like poly (3-4-ethylene dioxythiophene) (PEDOT) or polypyrrole (PPy) serves as a stable interface between the platinum of the electrode and the carbon-based nanomaterials through a co-electrodeposition process. Based on our comparison between different conducting polymers and the addition of CQD, the CNT–CQD–PPy modified microelectrode outperforms its counterparts: CNT–CQD–PEDOT, CNT–PPy, CNT–PEDOT, and bare Pt microelectrode. The CNT–CQD–PPy modified microelectrode has a higher conductivity, stability, and sensitivity while achieving a remarkable limit of detection (LOD) of 35.20 ± 0.77 nM. Using fast-scan cyclic voltammetry (FSCV), these modified electrodes successfully measured dopamine’s redox peaks while exhibiting consistent and reliable responses over extensive use. This electrode modification not only paves the way for real-time, precise dopamine sensing using microfabricated electrodes but also offers a novel electrochemical sensor for in vivo studies of neural network dynamics and neurological disorders. Full article

Shape memory and self-healing polymer nanocomposites have attracted considerable attention due to their modifiable properties and promising applications. The incorporation of nanomaterials (polypyrrole, carboxyl methyl cellulose, carbon nanotubes, titania nanotubes, graphene, graphene oxide, mesoporous silica) into these polymers has significantly enhanced their performance, opening up new avenues for diverse applications. The self-healing capability in polymer nanocomposites depends on several factors, including heat, quadruple hydrogen bonding, π–π stacking, Diels–Alder reactions, and metal–ligand coordination, which collectively govern the interactions within the composite materials. Among possible interactions, only quadruple hydrogen bonding between composite constituents has been shown to be effective in facilitating self-healing at approximately room temperature. Conversely, thermo-responsive self-healing and shape memory polymer nanocomposites require elevated temperatures to initiate the healing and recovery processes. Thermo-responsive (TRSMPs), light-actuated, magnetically actuated, and Electrically actuated Shape Memory Polymer Nanocomposite are discussed. This paper provides a comprehensive overview of the different types of interactions involved in SMP and SHP nanocomposites and examines their behavior at both room temperature and elevated temperature conditions, along with their biomedical applications. Among many applications of SMPs, special attention has been given to biomedical (drug delivery, orthodontics, tissue engineering, orthopedics, endovascular surgery), aerospace (hinges, space deployable structures, morphing aircrafts), textile (breathable fabrics, reinforced fabrics, self-healing electromagnetic interference shielding fabrics), sensor, electrical (triboelectric nanogenerators, information energy storage devices), electronic, paint and self-healing coating, and construction material (polymer cement composites) applications. Full article

Because of its considerable theoretical specific capacity and energy density, lithium–sulfur battery technology holds great potential to replace lithium-ion battery technology. However, a versatile, low-cost, and easily scalable bulk synthesis method is essential for translating bench-level development to large-scale production. This paper reports the design and synthesis of a new scalable sulfur cathode, S@CNT/PANI/PPyNT/TiO₂ (BTX). The rationally chosen cathode components suppress the migration of polysulfide intermediates via chemical interactions, enhance redox kinetics, and provide electrical conductivity to sulfur, rendering outstanding long-term cycling performance and strong initial specific capacity in terms of electrochemical performance. This cathode’s cell demonstrated an initial specific capacity of 740 mA h g⁻¹ at 0.2 C (with a capacity decay rate of 0.08% per cycle after 450 cycles). Full article

Heterostructured materials show great potential to enhance the specific capacity, rate performance and cycling lifespan of lithium-ion batteries owing to their unique interfaces, robust architectures, and synergistic effects. Herein, a polypyrrole (PPy)-coated nanotube-like Mo₃S₄/CoMo₂S₄ heterostructure is prepared by the hydrothermal and subsequent in situ polymerization methods. The well-designed nanotube-like structure is beneficial to relieve the serious volume changes and facilitate the infiltration of electrolytes during the charge/discharge process. The Mo₃S₄/CoMo₂S₄ heterostructure could effectively enhance the electrical conductivity and Li⁺ transport kinetics owing to the refined energy band structure and the internal electric field at the heterostructure interface. Moreover, the conductive PPy-coated layer could inhibit the obvious volume expansion like a firm armor and further avoid the pulverization of the active material and aggregation of generated products. Benefiting from the synergistic effects of the well-designed heterostructure and PPy-coated nanotube-like architecture, the prepared Mo₃S₄/CoMo₂S₄ heterostructure delivers high reversible capacity (1251.3 mAh g⁻¹ at 300 mA g⁻¹), superior rate performance (340.3 mAh g⁻¹ at 5.0 A g⁻¹) and excellent cycling lifespan (744.1 mAh g⁻¹ after 600 cycles at a current density of 2.0 A g⁻¹). Such a design concept provides a promising strategy towards heterostructure materials to enhance their lithium storage performances and boost their practical applications. Full article

Hybrid organic/inorganic conducting and magnetic composites of core–shell type have been prepared by in-situ coating of nickel microparticles with polypyrrole. Three series of syntheses have been made. In the first, pyrrole was oxidised with ammonium peroxydisulfate in water in the presence of various amounts of nickel and the composites contained up to 83 wt% of this metal. The second series used 0.1 M sulfuric acid as a reaction medium. Finally, the composites with polypyrrole nanotubes were prepared in water in the presence of structure-guiding methyl orange dye. The nanotubes have always been accompanied by the globular morphology. FTIR and Raman spectroscopies confirmed the formation of polypyrrole. The resistivity of composite powders of the order of tens to hundreds Ω cm was monitored as a function of pressure up to 10 MPa. The resistivity of composites slightly increased with increasing content of nickel. This apparent paradox is explained by the coating of nickel particles with polypyrrole, which prevents their contact and subsequent generation of metallic conducting pathways. Electrical properties were practically independent of the way of composite preparation or nickel content and were controlled by the polypyrrole phase. On the contrary, magnetic properties were determined exclusively by nickel content. The composites were used as a solid phase to prepare a magnetorheological fluid. The test showed better performance when compared with a different nickel system reported earlier. Full article