Effect of dopant and oxidant on the electrochemical properties of polyaniline/graphite nanoplate composites

Optimizing the synthesis parameters of polyaniline/graphite nanoplate (PANI/GNP) composite is essential to the final electrochemical performance. Herein, the electrochemical properties of PANI/GNP composites, prepared by in situ chemical polymerization using varying amounts of different oxidants, with or without the addition of 4‐dodecylbenzenesulfonic acid (DBSA) as dopant, were investigated. Cyclic voltammetric results suggested that a stoichiometric amount of the oxidant iron chloride (FeCl₃) was beneficial to the electrochemical properties of the composites. The use of ammonium persulfate (APS) instead of FeCl₃ as oxidant largely increased the actual PANI content, conductivity and specific capacitance of the PANI/GNP composites. The dopant DBSA increased the conductivity of the PANI/GNP composites but did not show a positive effect on the electrochemical behavior. The cyclic voltammograms of the PANI/GNP composites indicated that the pseudocapacitance of PANI contributes more than the electrical double‐layer capacitance of GNP to the capacitance of the composites, while the presence of GNP plays an essential role in the rate capability of the composites. In this study, PANI/GNP (1:1) composite synthesized with an APS to aniline molar ratio of 1 showed a balanced combination of high specific capacitance (180.5 F g^?1 at 20 mV s^?1) and good rate capability (78% retention at 100 mV s^?1). © 2018 Society of Chemical Industry     

Synthesis of graphene/vitamin C template-controlled polyaniline nanotubes composite for high performance supercapacitor electrode

A graphene nanosheet/polyaniline nanotube (GPNT) composite is prepared for the first time by in-situ chemical oxidative polymerization of aniline using vitamin C as a structure directing agent. The vitamin C molecules lead to the synthesis of polyaniline (PANI) nanotubes through the development of rod-like assembly by H-bonding in an aqueous medium. The initially synthesized graphene oxide/polyaniline nanotubes composite is reduced to graphene using hydrazine monohydrate followed by re-oxidation and protonation of the PANI to produce the GPNT nanocomposite. This novel composite showed a high specific capacitance of 534.37 F/g and an excellent energy density of 74.27 Wh/kg at a constant current of 0.5 mA. Besides, the GPNT composite exhibited excellent cycle life with 91.4% specific capacitance retained after 500 charge-discharge cycles. The excellent performance is due to the synergistic combination of graphene which provides good electrical conductivity and mechanical stability, and PANI nanofiber which deals with good redox activity.     

Preparation and performance of PANI–PVA composite film doped with HCl

The polyaniline (PANI)–poly (vinyl alcohol) (PVA) composite film doped with HCl was prepared by adopting PVA as matrix. Effects of PVA content and film drying temperature on properties of HCl–PANI–PVA composite film were studied. A comparison was made for tensile strength, elasticity, conductivity and thermal stability of PVA, HCl–PANI or HCl–PANI–PVA. PVA film presented the highest tensile strength and elasticity (150.8?MPa and 300.0%), but its conductivity was the lowest. The conductivity of HCl–PANI–PVA was the highest (1500?S?m^?1), and tensile strength and elasticity of HCl–PANI–PVA were higher than those of HCl–PANI. The order of their thermal stability is PVA?>?HCl–PANI?>?HCl–PANI–PVA before 260°C, and the order of their thermal stability is HCl–PANI?>?HCl–PANI–PVA?>?PVA after 260°C. At the same time, the structure and conductive mechanism of composite materials were characterised and analysed through infrared and scanning electron microscopy (SEM).     

Preparation and electrochemical investigation of the polyaniline/activated carbon nanocomposite for supercapacitor applications

The polyaniline (PANI)/activated carbon (AC) nanocomposite electrodes were prepared by electropolymerization of aniline monomers on the surface of AC/polyvinyl alcohol (PVA) electrodes for supercapacitor studies. Fourier transforms infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and scanning electron microscopy (SEM) analyses were performed to characterize the structure and morphology of the nanocomposite electrodes. The electrochemical properties of the prepared nanocomposite electrodes and the supercapacitive behavior of the PANI, AC, and AC/PANI/PVA electrodes were investigated using cyclic voltammetry (CV) and galvanostatic charge/discharge measurements, respectively. Morphological studies showed that a thin film of PANI has been uniformly deposited on the porous surface of AC electrode, and an ordered arrangement of nanostructures with interlinked porous network has been made. Electrochemical measurements showed that AC particles prevent the degradation of PANI chains during charge/discharge cycles. The specific capacitance of the AC/PANI/PVA nanocomposite electrode was 338.15 F/g which is higher than that of the pristine AC electrode (0.08 F/g). This is due to the contribution of PANI chains by their pseudocapacitance (redox reaction) properties. Although the specific capacitance of PANI electrode (378.57 F/g) was greater than that of the nanocomposite electrode, the cyclic stability of the PANI electrode was lower than that of the AC/PANI/PVA nanocomposite electrode.     

Effects of microstructural functional polyaniline layers on SPEEK/HPW proton exchange membranes

In this study, a method is developed to fabricate sulfonated poly (ether ether ketone)/phosphotungstic acid‐polyaniline (SPEEK/HPW‐PANI) membranes by in situ polymerization of aniline for the purpose of decreasing the weight loss of HPW in the membranes. The synthesis involves the production of a SPEEK/HPW hybrid membrane followed by different layer of PANI coatings on the membrane surface, and subsequent treatment using drying in vacuum procedures. The scanning electronic microscopy images showed that HPW had good compatibility with SPEEK polymers and energy dispersive X‐ray spectroscopy revealed the successfully doping with HPW and polymerization of PANI. The surface of SPEEK/HPW‐PANI becomes more compact than that of SPEEK/HPW and pure SPEEK, which may lead to reduce the water uptake and swelling property. The proton conductivity was found for the SPEEK/HPW‐PANI‐5 composite membrane (91.53 mS/cm at 80°C) higher than that of pure SPEEK membrane (68.72 mS/cm at 80°C). Better thermal stability was determined in both SPEEK/HPW and SPEEK/HPW‐PANI membranes than pristine SPEEK membrane. Therefore, PANI is a good potential coating for organic–inorganic hybrid e.g. SPEEK/HPW membrane materials to improve their hydrothermal stable properties and SPEEK/HPW PANI is a material that shows promise as a proton exchange membranes. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 41033.     

Preparation and characterization of conductive poly(vinyl alcohol)/polyaniline doped by dodecyl benzene sulfonic acid (PVA/PANDB) blend films

In this study a solution‐blend method is adopted to prepare conductive poly(vinyl alcohol)/polyaniline doped by dodecyl benzene sulfonic acid (PVA/PANDB) blend films. Emeraldine base (EB)‐type polyaniline (PANI) is dissolved in N‐methyl‐2‐pyrrolidinone (NMP) and then blended with PVA/dodecyl benzene sulfonic acid (DBSA) solution by various amounts. It is found that the electrical conductivity and the thermal degradation onset temperature of the PVA/PANDB blend film are increased as the amount of EB‐type PANI solution is increased. Fourier transform infrared (FTIR) spectra show that the intensity of the characteristic peak of the functional groups in the blend film is significantly changed as the amount of EB‐type PANI is changed. From optical microscopy examination, it indicates that the amount and size of green particles are increased with increasing the amount of EB‐type PANI solution. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3415–3422, 2007     

Facile preparation of soluble and conductive polyaniline in the presence of lignosulfonate and a constant magnetic field (0.4 T)

A convenient and economical method for preparing soluble conductive polyaniline nanoparticles is introduced in this article. Polyaniline (PANI) was prepared by utilizing a renewable resource calcium lignosulfonate (LS) as dopant in the presence (PANI‐LS‐M) and absence (PANI‐LS‐A) of a constant magnetic field (MF). Their structures and properties were systematically studied. Compared with PANI‐LS‐A, the PANI‐LS‐M exhibited a much higher conductivity, solubility, and thermo stability, which was due to the effective doping of the LS caused by the stretching and orientation effects of the MF. The conductivity of the PANI‐LS‐M (20.2 S/cm), which was prepared in the presence of a MF (0.4 T) with a polymerization yield of as much as 96%, was increased by four times compared with that of the PANI‐LS‐A (4.9 S/cm). Meanwhile, the solubility of the PANI‐LS‐M was two times higher than that of the PANI‐LS‐A in solvents such as NMP, dimethyl sulfoxide, dimethyl formamide, formic acid, and acetidin. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40467.     

AgNP/crystalline PANI/EBP-composite-based supercapacitor electrode with internal chemical interactions

In this article, polyaniline (PANI) was conformally coated on epoxide-functionalized buckypaper (EBP). Because of the presence of epoxide functional groups, chemical interactions occurred between oxygen in the epoxide groups and NH in the PANI. These chemical interactions were identified by peak shifts and intensity changes in Raman spectra. Additionally, crystalline peaks were clearly observed through X-ray diffraction. However, Raman peak changes or crystalline peaks were not observed in nonfunctionalized buckypaper (purified pristine buckypaper [PPBP])-based composites. Both hydrogen bonding and crystalline nature of EBP-PANI enhanced its electrical conductivity, producing a specific capacitance better than that of PPBP-PANI. Finally, Ag nanoparticles (AgNPs) were applied to EBP-PANI to further enhance its electrical conductivity. Owing to the presence of AgNPs and their interactions with the N in PANI, the specific capacitance of EBP-PANI-AgNP reached 915.62 F/g. These results emphasize the positive effect of chemical interactions and crystalline nature of EBP-based composites on their electrochemical performance. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 48164.     

Preparation of pseudocapacitor electrodes via electrodeposition of polyaniline on nonwoven carbon fiber fabrics

Aniline has been polymerized via electrodeposition onto various nonwoven carbon fiber fabric (CFF) substrates for use as a pseudocapacitive electrochemical capacitor. Four types of CFF were initially tested for double layer capacitance before polyaniline deposition, and again for specific capacitance after deposition. A binder‐free CFF was selected for further analysis due to its high capacitance change following PANI deposition (three orders of magnitude). The aniline monomer concentration, deposition potential, and deposition time were varied and resulting materials were characterized using chrono‐potentiometry, cyclic voltammetry, and scanning electron microscopy. The deposition potential range yielding highest capacitance was found to be between 0.744 and 0.777 V. A solution concentration of 0.5M aniline at a 20 min deposition time resulted in the highest specific capacitance (>80 F/g based on total electrode mass and >300 F/g based on PANI mass) within this study. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43315.     

Polyaniline/silver nanocomposites synthesized via UV–Vis‐assisted aniline polymerization with a reversed micellar microemulsion system

Polyaniline (PANI)/silver (Ag) nanocomposites were successfully synthesized within a sodium dodecyl sulfate reverse micro‐emulsion system and characterized by Fourier transform infrared spectroscopy, X‐ray diffraction, ultraviolet spectrometry, thermogravimetric analysis, scanning electron microscopy, transmission electron microscopy, and electrochemical methods. The results show that the core‐shell nanoparticles of less than 100 nm may be synthesized with PANI as shell formed around a core of nanoparticle. PANI/Ag nanocomposite prepared by this method has better thermal stability, higher conductivity, and electrochemical performance. The maximum conductivity (95.5 S/cm) was obtained when W₀ (water‐oil ratio) is 22. Cyclic voltammograms results show that PANI/Ag prepared by this method has a high response current and large capacitance. Polarization results show that E_corr (174.1 mV) and I_corr (50.6 μA/cm²) are better than the results for PANI and for PANI/Ag prepared by micro‐emulsion method. PANI/Ag nanocomposites prepared by the current method have potential applications in electrode materials, capacitors, conductive adhesives, and anticorrosion materials. POLYM. COMPOS. 37:1064–1071, 2016. © 2014 Society of Plastics Engineers     

导电高分子聚苯胺的合成及应用

聚苯胺(PANI)是研究最为广泛的导电高分子材料之一。综述了聚苯胺的结构、特性及几种合成聚苯胺的方法,介绍了聚苯胺的掺杂方法及聚苯胺的应用前景。     

Determination of the specific capacitance of conducting polymer/nanotubes composite electrodes using different cell configurations

Composite materials containing 20 wt.% of multiwalled carbon nanotubes (MWNTs) and 80 wt.% of chemically formed conducting polymers (ECP) as polyaniline (PANI) and polypyrrole (PPy) have been prepared and used for supercapacitor electrodes. The well conducting properties of MWNTs and their available mesoporosity allow a good charge propagation in the composites. Moreover, due to the good resiliency of MWNTs, an excellent stability of the supercapacitor electrodes is observed. It has been shown that the capacitance values for the composites strongly depend on the cell construction. In the case of three electrode cells, extremely high values can be found from 250 to 1100 F/g, however in the two electrode cell much smaller specific capacitance values of 190 F/g for PPy/MWNTs and 360 F/g for PANI/MWNTs have been measured. It highlights the fact that only two-electrode cells allow a good estimation of materials performance in electrochemical capacitors. The applied voltage was found to be the key factor influencing the specific capacitance of nanocomposites. For operating each electrode in its optimal potential range, asymmetric capacitors have been built with PPy/MWNTs as negative and PANI/MWNTs as positive electrodes giving capacitance values of 320 F/g per electrode material.     

Electrically conductive nanocomposites of polyaniline with poly(vinyl alcohol) and methylcellulose

Electrically conductive nanocomposites of HCl‐doped polyaniline (PANI–HCl) nanocolloid particles with water‐soluble and film‐forming polymers such as poly(vinyl alcohol) (PVA) and methylcellulose (MC) were prepared by the redispersion of preformed MC‐coated submicrometric PANI–HCl particles in PVA and MC solutions under sonication for 1 h and the casting of the films from the dispersions followed by drying. The submicrometric polyaniline (PANI) particles were prepared by the oxidative dispersion polymerization of aniline in an acidic (1.25M HCl) aqueous ethanol (30 : 70) medium with MC as a steric stabilizer. The particles contained 4.7 wt % MC and had a conductivity of 7.4 S/cm. They had an oblong shape of 203 nm (length) and 137 nm (breadth). Sonication broke the oblong‐shaped particles to sizes of ～10 nm in the PVA matrix and ～60 nm in the MC matrix. The electrical conductivity of these films was measured, and the percolation threshold was determined. The composites had the characteristics of a low percolation threshold at a volume fraction of PANI of 2.5 × 10^?2 in the PVA matrix and at a volume fraction of 3.7 × 10^?2 in the MC matrix. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Influence of multi-walled carbon nanotubes on the electrochemical performance of graphene nanocomposites for supercapacitor electrodes

In this work, multi-walled carbon nanotube (MWNT) bonded graphene (M-GR) composites were prepared using the chemical reduction of graphite oxide (GO) and acid treated MWNTs with different ratios. The M-GR/polyaniline (PANI) nanocomposites (M-GR/PANI) were prepared using oxidation polymerization. The effect of the M-GR ratio on the electrochemical performances of the M-GR/PANI was investigated. It was found that the substrate 2D graphene was coated with 1D MWNTs by chemical reduction and the M-GR was further coated with PANI, leading to increased electrical properties by the π–π interaction between the M-GR and PANI. In addition, the electrochemical performances, such as the current density, charge–discharge, and specific capacitance of the M-GR/PANI were higher than those of graphene/PANI and the highest specific capacitance (1118 F/g) of the composites was obtained at a scan rate of 0.1 A/g for the PANI containing a 0.5 M-GR ratio compared to 191 F/g for the graphene/PANI. The dispersion of the MWNTs onto the graphene surface and the ratio of M-GR had a pronounced effect on the electrochemical performance of the PANI-based composites, which was attributed to the highly conductive pathway created by the M-GR incorporated in the PANI-based composites and the synergistic effect between M-GR and PANI.     

Synthesis and characterization of conductive composite films of polyisoprene/PA12@ PANI

Polyamide@Polyaniline powders of core‐shell structure are known to have reduced conduction thresholds useful to maintain the mechanical and optical properties of the matrix. However, difficulties emerge at the synthesis stage, where dissolving the matrix without damaging the core‐shell particles becomes a challenge. The present solution avoids using solvents. Conductive polymer films containing solid Polyamide@Polyaniline particles are elaborated by UV photoreticulation of a liquid polyisoprene serving as a matrix. The conductive powders are obtained by in‐situ polymerization of aniline in presence of polyamide 12 (PA12) at room temperature using Dodecyl benzene sulfonic doping acid and Ammonium persulfate oxidant. Obtained films exhibit low percolation threshold compared to those containing pure solid polyaniline (PANI) particles even more conductive. This threshold is shown to be about 1.5 wt % of PANI. Films show good electrical conductivity and thermal stability up to 200°C allowing their use as antistatic polymer films for high temperatures. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39833.     

Conductive and electroactive composite paper reinforced by coating of polyaniline on lignocelluloses fibers

Direct use of lignocelluloses fibers as substrate for fabrication of conductive, electroactive, biodegradable, and low‐cost electrode materials are in demand for high‐tech applications of ion‐exchange and energy storage devices. This article presents the preparation and characterizations of conductive and electroactive lignocelluloses‐polyaniline (cellulose/PANI) composite paper. Lignocelluloses fibers were directly collected from the stem of self‐growing plant, Typha Angusitfolia, and subsequently coated with the conductive and electroactive layer of PANI through chemical synthesis. Individual PANI‐coated lignocelluloses fibers were converted into sheet and further characterized with Scanning Electron Microscopy, Fourier Transform Infrared, Thermogravimetric Analysis, electronic conductivity, and Cyclic Voltammetry. Cellulose/PANI composite paper revealed superior thermal characteristics and used as a working electrode in three different electrolytes for ion‐exchange properties. Conductive composite paper (CCP) showed the charge storage capacity of ～52 C/g at scan rate of 5 mV/s in 2M HCl solution. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42293.     

Preparation of polyaniline/phosphorylated poly(vinyl alcohol) nanoparticles and their aqueous redispersion stability

A novel approach for the preparation of the colloidal conducting polyaniline (PANI) nanoparticles was developed. The polyaniline/partially phosphorylated poly(vinyl alcohol)(PANI/P‐PVA) nanoparticles were prepared by the chemical oxidative dispersion polymerization of aniline monomer in 1.0 M HCl aqueous media with the partially phosphorylated poly(vinyl alcohol) (P‐PVA) as the stabilizer and codopant. The PANI/P‐PVA nanoparticles were characterized by transmission electron microscopy (TEM), Fourier transform infrared (FTIR), thermal gravimetric analysis (TGA), electrical conductivity measurement, and redispersion stability testing. All the results were compared with the properties of the conventional polyaniline in the emeraldine salt form (PANI ES). It was found that the P‐PVA/aniline feeding ratio obviously affected the morphology, redispersion stability and electrical conductivity of the PANI/P‐PVA nanoparticles. When the P‐PVA/aniline feeding ratio ranged from 50 to 60 wt %, the PANI/P‐PVA nanoparticles showed spherical shape with good uniformity, significant redispersion stability in aqueous media, and good electrical conductivity up to 7 S/cm. © 2010 American Institute of Chemical Engineers AIChE J, 2011     

Synthesis of copolymer of aniline and pyrrole by inverted emulsion polymerization method for supercapacitor

Copolymer of aniline and pyrrole was synthesized by inverted emulsion polymerization method by oxidizing aniline and pyrrole using benzoyl peroxide in presence of sodium laurylsulphate surfactant and p‐toluenesulphonic acid. Copolymer samples were characterized by infrared, X‐ray diffraction and scanning electron microscopic techniques and compared their properties with the corresponding homopolymers. The optimum reaction conditions for the preparation of copolymer with reasonably good yield (1.72 g) and conductivity (7.3 × 10^?2 S/cm) were established. The synthesis procedure was extended to prepare copolymer samples using various protonic acids. Electrochemical characterization such as cyclic voltammetry, charge‐discharge and impedance were carried out on symmetrical supercapacitor cell consists of poly(aniline‐co‐pyrrole)‐p‐toluenesulfonic acid salt, wherein, the copolymer salt was synthesized using equal amount of aniline and pyrrole monomers. The values of specific capacitance, energy and power densities for poly(aniline‐co‐pyrrole)‐p‐toluenesulfonic acid system (PANI‐PPy) were calculated from charge‐discharge studies and are found to be 21 F/g, 5.7 Wh/Kg and 100 W/Kg respectively. Impedance analysis showed specific capacitance value (57 F/g) at 0.01 Hz at 0.22 V. Among the copolymer salts, copolymer prepared with sulfuric acid showed higher capacitance (66 F/g). © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Al掺杂NiCo2S4电极材料的制备及其电化学性能

元素掺杂可以调节电极材料的电子结构，提高材料的电化学活性。以导电碳布为基底，氯化镍、氯化钴为原料，硝酸铝为铝源，通过两步水热法成功在碳布（CC）上生长铝掺杂的NiCo2S4复合电极材料（CC@Al-NiCo2S4）。扫描电子显微镜显示CC@Al-NiCo2S4具有中空纳米管结构，该结构可以提供大量反应活性位点；X射线光电子能谱表征得知Al主要以Al3+的形式存在于CC@NiCo2S4中，可以提高CC@NiCo2S4的导电性。电化学性能测试结果表明，当电流密度为1 A/g时，原始CC@NiCo2S4电极的比电容为844.5 F/g，Al掺杂CC@NiCo2S4的比电容为1515.8 F/g；且在6 A/g的电流密度下经过10000次循环后，CC@Al-NiCo2S4的电容保持率高达87.8%，表明Al掺杂能够显著地提高CC@NiCo2S4的比电容和循环稳定性。     

PEDOT solid-state polymer supercapacitor assembled with a KI-doped gel polymer electrolyte

Solid-state polymer supercapacitors (SSP-SCs) have vast potential for future development due to their compact, safe, environment-friendly, and facile designing. Thus, prevalent researches have been explored in this area. In this article, poly(3,4-ethylenedioxythiophene) (PEDOT) SSP-SCs were assembled by using poly(3,4-ethylenedioxythiophene)/carbon paper (PEDOT/CP) as electrodes and polyvinyl alcohol/sulfuric acid/potassium iodide (PVA/H₂SO₄/KI) as the gel polymer electrolyte. The effect of KI content on the electrochemical performance of the SC was studied by cyclic voltammetry, galvanostatic charge–discharge measurements (GCD), and electrochemical impedance spectroscopy. The results indicated that the PEDOT SSP-SC has excellent electrochemical properties when KI doping amount was 60 wt %. The introduction of KI increased the specific capacitance due to the improved ionic conductivity and additional pseudocapacitance reaction at the electrode–electrolyte interface. The PEDOT SSP-SC showed high energy and power densities of 451.32 Wh kg⁻¹ and 13.29 kW kg⁻¹, respectively, as well as a specific capacitance of 352.59 F g⁻¹ for a discharge current of 1 mA cm⁻². In addition, after 1000 GCD cycles, the PVA/H₂SO₄/KI-based PEDOT SSP-SC showed capacitance retention of 74.08%. Therefore, the SC exhibits outstanding energy and power density and good cycle stability and has great potential to be used in high-energy density equipment. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48723.