PANI Electrode Research Articles

Super capacitive electrode performance analysis of facile synthesized α-Fe2O3 aerogel and its nanocomposite with in-situ formed polyaniline (α-Fe2O3/PANI)

This paper presents the synthesis of an α-Fe2O3-assisted polyaniline (α-Fe2O3/PANI) nanocomposite using a straightforward two-step process. Initially, α-Fe2O3 aerogels with cratered nanohexagon structures are synthesized through a solution combustion method assisted by noni (Morinda citrifolia) fruit extract. In the second step, these nanohexagons facilitate the preparation of α-Fe2O3/PANI via in-situ chemical oxidative polymerization of anilinium chloride. The structural, optical, and morphological properties were characterized using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and scanning electron microscopy with energy-dispersive X-ray analysis (SEM-EDAX). Electrical conductivity, wettability, and electrochemical properties of the prepared materials were assessed. The results indicate that the 2D cratered α-Fe2O3 aerogel is effectively embedded within PANI, forming a modified nano α-Fe2O3/PANI composite. The composite exhibited altered DC conductivity and electrolyte wettability. After 200 cycles of cyclic voltammetry (CV), the specific capacitance of the nano α-Fe2O3/PANI was determined to be 153 Fg⁻¹ at a scan rate of 10 mVs⁻¹, retaining approximately 90 % of its cycle stability. Electrochemical impedance spectroscopy (EIS) revealed significantly lower charge transfer and equivalent series resistance values for the nano α-Fe2O3/PANI electrode compared to the pure α-Fe2O3-based electrode. Galvanostatic charge-discharge (GCD) tests further demonstrated the superior electrochemical performance of the α-Fe2O3/PANI nanocomposite electrode. Therefore, this α-Fe2O3/PANI is an advanced conducting polymeric electrode for electrochemical applications.

Non-Substituted Imidazolium-Based Electrolytes as Potential Alternatives to the Conventional Acidic Electrolytes of Polyaniline-Based Electrode Materials for Supercapacitors.

Although disubstituted imidazolium cation is sterically crowded, hundreds of ionic liquids based on this cation have been reported as electrolytes for energy storage devices. In contrast to disubstituted imidazolium, non-substituted imidazolium is uncrowded sterically and has not yet been investigated as an electrolyte, to the best of our knowledge. Hence, imidazolium hydrogen sulfate [Imi][HSO4], in mixture with water, was studied as an electrolyte for PANI-based electrode materials. For comparison, pyrrolidinium with hydrogen sulfate or p-toluene sulfonate ([Pyrr][HSO4] or [Pyrr][PTS]), in mixture with water, were also investigated as alternatives to the conventional electrolyte (i.e., aqueous H2SO4) for PANI electrodes. Walden plots of binary mixture ionic liquid-water weight ratios with the optimal ionic conductivity (i.e., [Imi][HSO4]/water 48/52 wt% (195.1 mS/cm), [Pyrr][HSO4]/water 41/59 wt% (186.6 mS/cm), and [Pyrr][PTS]/water 48/52 wt% (43.4 mS/cm) along with the electrochemical performances of PANI in these binary mixtures showed that [Pyrr][HSO4]aq or [Imi][HSO4]aq are convenient electrolytes for PANI/PIL, as opposed to [Pyrr][PTS]aq. Furthermore, replacing the conventional aqueous electrolyte H2SO4 with [Imi][HSO4] aq increased the specific capacitance of PANI/PIL from 249.8 to 268.5 F/g at 15 mV/s. Moreover, PANI/PIL electrodes displayed a quasi-ideal capacitive behavior in [Imi][HSO4]aq (the correction factor of CPE4 was 0.99). This primary study has shown that non-substituted imidazolium as an electrolyte could enhance the electrochemical performances of PANI electrodes and could be a good alternative to the conventional electrolyte.

Improved Na+ adsorption performance and storage mechanism of cobalt hexacyanoferrate/polyaniline composite during the hybrid capacitive deionization process

In order to realize high desalting capacity of capacitive deionization (CDI) system, cobalt hexacyanoferrate/polyaniline (CoHCF/PANI) composite with hollow hierarchical tubular structure was finely prepared by employing conductive hollow PANI tube as the interconnection skeleton for CoHCF cubic particles grown in situ, thereby endowing this composite with good conductivity, abundant redox active sites and stable structure. The synergistic effect between the CoHCF layer and PANI layer makes the CoHCF/PANI electrode possess superior specific capacitance (263.8F·g−1) and high contribution of the capacitance behavior (87.8 %) at 5 mV·s−1. Compared with either the single PANI or CoHCF electrode, the CoHCF/PANI electrode exhibits outstanding salt adsorption capacity (30.48 mg·g−1), rapid salt adsorption rate (3.66 mg·g−1·min−1) and excellent cycle stability (retention rate 98.1 %). Different from the CoHCF/PANI(+)‖AC(−) cell, there is no inversion peak in the AC(+)‖CoHCF/PANI(−) cell, which testifies that the CoHCF/PANI electrode is easier to capture Na+ ions. Based on the XPS spectra before and after desalination tests, the Na+ adsorption mechanism of the CoHCF/PANI electrode as cathode for the hybrid capacitive deionization (HCDI) system was further explored. It is found that the change of element valence in CoHCF/PANI composites (reduction of Fe3+ to Fe2+ and Co3+ to Co2+ in CoHCF, partial reduction of −C = N+ to −N–H- in PANI) is the main factor leading to Na+ intercalation. This study emphasizes the significance for fine design of the electrode material and strategic configuration of the HCDI cell.

High-performance supercapacitor based on NiCo2S4/g-C3N4/polyaniline deposited on carbon cloth for structural stability

Although the synthesis of NiCo2S4(NCS)/g-C3N4(GCN)/PANI as an electroactive material has been extensively documented, assembling a Nickel cobalt sulfide (NCS) electrode with outstanding electrochemical efficiency at high current density is still difficult. In this work, the fabrication of a supercapacitor (Sc) electrode of petal-like NiCo2S4/g-C3N4/PANI using a hydrothermal, thermal condensation, and chemical oxidative polymerization method was done. In this nanocomposite, g-C3N4 stabilized the metal atoms and PANI integration considerably improves ion mobility, leading to rapid charge transmission. Due to improvement in electron mobility, the eventual NiCo2S4/g-C3N4(0.40wt%) /PANI(A-3) electrode had shown a specific capacitance (Cs) of 3.4 F/cm2 (1799.07 F/g) with 90% retention and 2700 cycles at the current density of 2 mA/cm2. A good rate capacity of 87.36% at 5 mA/cm2, 82.92% at 10 mA/cm2, and a 50.35% decline of its original capacitance at a high charge/discharge current density of 20 mA/cm2. This work demonstrates that the produced NiCo2S4/g-C3N4/PANI electrode has a high potential for use in energy storage gadget technologies.

Nitrogen-doped graphene quantum dots/co-doped PANI binary nanocomposites as high-performance supercapacitor electrode materials

In this paper, a suitable and high-performance electrode material for practical applications was developed using a simple two-step approach. Here, we report that nitrogen-doped graphene quantum dots with co-doped polyaniline (N-GQDs-PANI) were fabricated by in situ polymerization as supercapacitor electrodes and that the effect of the amount of N-GQDs in the electrode material on the electrochemical performance was investigated. The integration of N-GQDs into co-doped PANI structure prevented the agglomeration of PANI and enabled the fabrication of N-GQDs as thin film on the surface. This modification improved the charge transfer of the N-GQDs-PANI electrode compared to N-GQDs and pure PANI electrodes, allowing it to exhibit superior electrochemical performance. The N-GQDs-PANI electrode has a specific capacitance of 503 F/g at a current density of 5 A/g with a capacitance retention of about 91.9 % after 10000 charge/discharge cycles.

Hydrogen Peroxide (H2O2) Biosensor Based on the Conducting Polymer Using Self-Assembly Technique

Biosensors are in principle fabricated by immobilized biomaterials on a detector membrane and combining them with electrochemical equipment. The applications of enzyme-based biosensors can be explored such as in the process of gas detection, medicine, pathogen detection and detection of toxic levels of substances before and after bioremediation. In this study, H2O2 detection was performed using HRP/PANI, HRP/PPY, HRP/PT and HRP/PT/PPY/PANI layers. The HRP/PANI layer from Variable Pressure Scanning Electron Microscopy (VPSEM) image exhibited a dry surface. The HRP/PPY layer exhibited a surface with agglomerate molecules. The HRP/PT layer, on the hand, exhibited a layer surface with almost the same molecular size. This is confirmed by the higher surface roughness value for HRP/PPY compared to other layers obtained via characterization with Atomic Force Microscopy (AFM). The increasing current response for all three layers was arranged in HRP/PANI> HRP/PT> HRP/PPY. VPSEM and AFM images exhibited surfaces with molecules being in an agglomeration state after the H2O2 detection process. In terms of current response, the response rate of H2O2on the surface of the HRP/PT/PPY/PANI electrode caused the current response obtained to be fast. The roughness value increased with time due to the reaction that took place between the surface of the HRP/PT/PPY/PANI layer with H2O2. The day-based current response showed that day 1 to day 14 exhibited a uniform graph pattern but from day 21 to day 30 there was a change in the graph pattern due to the HRP/PT/PPY/PANI layer undergoing degradation. The activity of the HRP enzyme was studied by looking at its absorption effect for 30 days. From day 1 to day 14, there was a difference in the overall rate of absorption. However, from day 21 to day 30, the rate of absorption remained constant which explains the slowing down of HRP activity.

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

AbstractA facile ternary nanocomposite comprising of polyaniline, titanium dioxide, polypyrrole, that is, PANI‐TiO2‐PPy was synthesized by in‐situ chemical oxidative polymerization method and fabricated as an active electrode material for supercapacitor applications. The phase, morphology, chemical composition, electronic states and thermal behavior of PANI‐TiO2‐PPy were analyzed using XRD, FESEM/EDAX, FTIR, XPS, and TGA techniques. CV profile of PANI‐TiO2‐PPy electrode exhibits the highest specific capacitance (600 F g−1) at 1 mV/s in 1 M KOH electrolyte, which is higher than the PANI (31 F g−1), PPy (120 F g−1), and TiO2 (398 F g−1) electrodes. The charge storage mechanism of PANI‐TiO2‐PPy electrode was also explored in 1 M H2SO4 and 1 M Na2SO4 electrolytes; wherein the capacitive behavior of ternary electrode was found to be superior in alkaline electrolyte compared to acidic and neutral electrolytes. From GCD, the ternary electrode exhibited the longest charge/discharge curve when compared to unary electrodes, which affirms the improved energy storage capacity of PANI‐TiO2‐PPy. The lower ESR value (0.90 Ω) exhibited by ternary electrode in comparison with PANI (1.75 Ω), PPy (1.59 Ω), and TiO2 (2.11 Ω) and 92% of capacitive retention after 2500 charge/discharge cycles suggest that PANI‐TiO2‐PPy could be a suitable active electrode for supercapacitors.

Polymer incorporated with graphene oxide composite for high electrochemical performance

In this present work the Polyaniline/Graphene Oxide composite (PANI/GO) synthesized by chemical polymerization. XRD pattern shows crystal plane (200) and (002) reveals the presence of GO in the PANI/GO composite, UV-absorption spectra exhibits three distinguished peaks at 235 nm is corresponding to the π to π* transition of C–C in GO, 354 nm and 642 nm indexed with bi-polaronic transition of PANI in red shift, surface morphology revels the PANI homogenously dispersed on the surface of GO. CV curve indicates the PANI/GO composite electrode current rate and surface area 5 fold higher than the PANI electrode, which is suggested that the PANI/GO composite electrode is highly suitable for energy storage devices. EIS spectra show the semi-circle arc, and Rct value of PANI is found to be 28.61 Ω and PANI/GO composite electrode found to be 16.15 Ω. These results represent the PANI/GO composite electrode having more storage capacitive than the PANI, it shows high electrical conductivity, and also enhances the electrochemical performance.

A binder-free CF|PANI composite electrode with excellent capacitance for asymmetric supercapacitors

In this work, carbon fiber and polyaniline (CF|PANI) composites are prepared by using an electrochemical polymerization method. The morphology and composition characterization results show that the PANI nanospheres are successfully synthesized and uniformly coated on the CF. When the electrodeposition period is 300 cycles, the as-prepared CF|PANI electrode exhibits good specific capacitance of 231.63 F/g at 1 A/g, high performance of 98.14% retention rate from 0.5 to 20 A/g, and excellent cycle stability with only 0.96% capacity loss after 1000 cycles. This is ascribed to the internal resistance that was significantly reduced without binders, which helps to the CF|PANI electrode maintains high operating potential and pseudo-capacitance performance at high current density. The symmetrical supercapacitor based on two CF|PANI electrodes connecting by acidic PVA-H2SO4 gel electrolyte exhibits an energy density of 6.55 W·h/kg at a power density of 564.37 W/kg. In addition, the asymmetric supercapacitor based on MoS2|MWCNTs and CF|PANI electrodes with neutral PVA-Na2SO4 gel electrolyte shows an energy density of 16.12 W·h/kg at a power density of 525.03 W/kg. These results indicate that the low internal resistance contributes to the high energy density of symmetrical supercapacitors and asymmetric supercapacitors at high current density and high power density, which is significant for its practical application.

Strategic Electrochemical Determination of Nitrate over Polyaniline/Multi-Walled Carbon Nanotubes-Gum Arabic Architecture.

Significant agricultural and industrial activities necessitate the regular monitoring of nitrate (NO3−) ions levels in feed and groundwater. The current comparative study discloses an innovative user-friendly electrochemical approach for the determination of NO3− over polyaniline (PAni)-based modified electrodes. The electrochemical sensors concocted with PAni, multi-walled carbon nanotubes (CNT), and gum arabic (GA). The unique electrode material GA@PAni-CNT was synthesized by facile one-pot catalytic polymerization of aniline (Ani) with FeCl3/H2O2 in the presence of CNT and GA as integral components. As revealed by cyclic voltammetry (CV), the anchoring/retention of NO3− followed by reduction is proposed to occur when a GA@PAni-CNT electrode is immersed in phosphate buffer electrolyte containing NO3− that eventually results in a significantly higher redox activity of the GA@PAni-CNT electrode upon potential scan. The mechanism of NO3− anchoring may be associated with the non-redox transition of leucomeraldine salt (LS) into emeraldine salt (ES) and the generation of nitrite (NO2−) ions. As a result, the oxidation current produced by CV for redox transition of ES ↔ pernigraniline (PN) was ~9 times of that obtained with GA@PAni-CNT electrode and phosphate buffer electrolyte, thus achieving indirect NO3− voltammetric determination of the GA@PAni-CNT electrode. The prepared GA@PAni-CNT electrode displayed a higher charge transfer ability as compared to that of PAni-CNT and PAni electrodes. The optimum square wave voltammetric (SWV) response resulted in two linear concentration ranges of 1–10 (R2 = 0.9995) and 15–50 µM (R2 = 0.9988) with a detection limit of 0.42 µM, which is significantly lower. The GA@PAni-CNT electrode demonstrated the best detection, sensitivity, and performance among the investigated electrodes for indirect voltammetric determination of NO3− that portrayed the possibility of utilizing GA—stabilized PAni and CNT nanocomposite materials in additional electrochemical sensing applications.

Direct Chemical Oxidative Polymerization of Polymelamine and its Copolymerization with Aniline for Hydrogel Supercapacitor Electrodes

In this work, we report for the first time, the direct chemical oxidative polymerization of melamine (MA) to obtain polymelamine (PME) via the initiation of a common oxidant, ammonium peroxydisulfate (APS). Characterizations of MA and PME were carried out by SEM, FTIR, XPS, NMR, and TGA measurements, and the results were compared with those from published works to verify the successful synthesis of PME. The PME was further used to initiate aniline (ANI) monomers, and an emeraldine product, called PAMx, was interestingly afforded. Moreover, APS oxidant was added into the solution as a second initiator for the polymerization of the residual monomers and remaining reactive sites on PAMx, thereby directly forming the hydrogel electrode, and labeled as PAMxS. The electrochemical performances of the PANI and PAMxS hydrogel supercapacitor electrodes were compared, and a high specific capacitance of 568 F g−1 at scan rate of 2 mV s−1 was obtained for PAM6S compared with 371 F g−1 for PANI. The facile direct oxidative synthesis approach for the preparation of PME provides an efficient route for its mass production, and its initiation ability with ANI monomers holds interesting potentials for the construction of macromolecules in conductive polymer applications.

An ultra-high power density supercapacitor: Cu(II) phthalocyanine tetrasulfonic acid tetrasodium salt doped polyaniline

In this study, an excellent electrode and supercapacitor performance with aqueous electrolyte exhibiting high operating voltage was obtained. Cu(II) phthalocyanine tetrasulfonic acid tetrasodium salt (CuPcTs) was used as a dopant in the polymerization of aniline on carbon felt electrode (CFt) by one-step hydrothermal method. Scanning electron microscopy (SEM) was used to analyze the morphological structure of PANI and CuPcTs doped PANI electrodes. Chemical analysis of the electrodes was performed using X-Ray diffractometry (XRD) and Fourier transform infrared spectroscopy (FT-IR); thermal properties of the electrodes were investigated using thermogravimetric analysis (TG/DTA). The surface area and pore volume of the electrodes were investigated using Brunauer-Emmett-Teller (BET) analysis. The electrochemical properties of the electrodes were investigated using cyclic voltammetry (CV), galvanostatic charge-discharge (GCD) and electrochemical impedance spectroscopy (EIS) methods. With the addition of CuPcTs and the use of graphite plate (GP) as the counter electrode, an asymmetrical supercapacitor was created for pseudocapacitive supercapacitors, in which the properties of redox materials were improved. CuPcTs doped PANI electrode showed a high specific capacitance of 982.2 F g −1 at 5 mV s −1 and showed excellent rate capability at different current densities of charge-discharge tests. Furthermore, wide operating-voltage of 3.2 V exhibited an ultra-high energy density value of 12800 W kg −1 and had an energy density of 764.4 Wh kg −1 . The electrode and supercapacitor displayed retention of capacitance performances of 91.4% and 79.7% after 1000 and 5000 cycles in aqueous electrolyte, respectively. • CuPcTs doped PANI carbon felt electrode was developed for supercapacitor applications. • 3.2 V wide operating voltage supercapacitor with 3.0 M KCI electrolyte. • A high specific capacitance of 982.2 F g −1 at 5 mV s −1 and excellent rate capability at charge-discharge tests. • A -maximum energy density of 764.4 Wh kg −1 and ultra-high power density of 12800 W kg −1 can be obtained for device.

Novel manganese oxide decorated polyaniline/graphitic carbon nitride nanohybrid material for efficient supercapacitor application

Supercapacitors are gaining popularity as a component in energy storage systems due to their quick charge/discharge rates and high specific power. A facile method is introduced in this research to fabricate a novel ternary nanocomposite-based manganese oxide decorated on polyaniline/graphitic carbon nitride (PANI-GCN) nanohybrid modified graphite sheet (GC) electrode via the electrochemical deposition method. As-prepared nanocomposite modified electrode morphology, elemental analysis, surface functionalities studies, and crystalline behavior are proved using SEM, Energy Dispersive Analysis, FT-IR, and XRD techniques. The electrochemical measurements are obtained by CV, GCD, and EIS. For Bare GS, PANI, and PANI-GCN, the solution resistance (Rs) that gauges the ionic conductivity across the electrolyte, was measured to be 60.57 Ω, 7.28 Ω, and 6.19 Ω, respectively. A greater specific capacitance of 318 F/g at 1 A/g was displayed by the developed MnO2@PANI-GCN electrode and lower charge transfer resistance over the PANI and PANI-GCN electrodes. Furthermore, the proposed electrode has shown the capacitive retention of 80.62% up to 1000 cycles. These results indicate that the ternary nanocomposite MnO2@PANI-GCN shows significant electrochemical properties towards energy storage applications.

A high-voltage aqueous rechargeable zinc-polyaniline hybrid battery achieved by decoupling alkali–acid electrolyte

Aqueous Zinc–polyaniline (Zn-PANI) batteries have attracted attention due to their high safety and low cost but they suffer from the limited water electrochemical window (1.23 V), fast capacitance decay derived from the structural instability of PANI, and poor electroactivity of PANI in low acidic electrolytes due to its de-protonation. Herein, we firstly report a decoupling design of acid-alkaline electrolyte to maximize the electrochemical window of the electrolyte and optimize the redox chemistry of both PANI cathode and Zn anode. The PANI electrode delivers a higher stability in H2SO4 electrolytes than the conventional Zn2+ neutral or weakly acidic electrolytes. The optimized electrolyte-decoupling Zn-PANI (EDZPB) battery exhibits an expanded electrochemical stability window over 2 V, a high capacity of 213.3 mAh g−1 at 0.1 A g−1, and a high cycling life stability (only 6.8% loss after 3000 cycles), showing the great potential of the design for applications in large-scale energy storage.

Nanotubular Polyaniline/Reduced Graphene Oxide Composite Synthesized from a Natural Halloysite Template for Application as a High Performance Supercapacitor Electrode

AbstractPolyaniline (PANI) is a promising material for developing high‐performance supercapacitors, and adopting some specific templates to design one‐dimensional nanostructured PANI electrode is considered to be a key strategy to enable high performance supercapacitors. Here, the nano‐tubular PANI(HNTs) were successfully achieved by using the natural tubular halloysite as hard template with low cost, and the PANI(HNTs) were further compounded with reduced graphene oxide (rGO) to prepare a binder‐free, self‐supporting PANI(HNTs)‐rGO composite electrode. The characterization tests of Infrared, Raman and XRD diffraction proved that PANI (HNTs) and PANI (HNTs)‐rGO composite material were successfully synthesized. SEM and TEM verified the nanotubular structure of PANI(HNTs) and the three‐dimensional network structure of PANI(HNTs)‐rGO. Owing to the rGO’ positive effect on the PANI(HNTs) electrode, the composite electrode exhibited excellent specific capacity performance of 762 F g−1, 660 F g−1, 595 F g−1, 545 F g−1 and 493 F g−1 at current densities of 1 A g−1, 2 A g−1, 5 A g−1, 10 A g−1, and 20 A g−1, respectively. This work prove that natural clay minerals have good application prospects in the design of nanostructured electrodes of conductive polymers (CPs) or other electrode materials for energy storage devices.

Protonating imine sites of polyaniline for aqueous zinc batteries.

PANI materials usually contain a certain amount of insulating components, e.g., imine (N-) and amine (-NH-) groups, limiting the electrochemical redox of PANI. Herein, we proposed a simple protonation strategy to activate the redox couples of the PANI cathode for aqueous Zn batteries, during which the insulating N- groups are partially converted to the conductive emeraldine salt (polarons -NH+-), endowing PANI more active sites and enhanced conductivity. The A-PANI electrode realizes efficient transitions of leucoemeraldine/emeraldine and emeraldine/pernigraniline, achieving a high discharge capacity of 183 mA h g-1, long life span, and good energy density of 178 W h kg-1 at the power density of 680 W kg-1. These values are significantly superior to those of the original PANI electrode, indicating the high efficiency of the proposed strategy. This simple protonation method could be applicable for many electrochemical devices, such as supercapacitors, sensors, and batteries.

Effect of polyaniline/FeS2 composite and usages of alternates counter electrode for dye-sensitized solar cells

Dye-sensitized solar cells (DSSCs) associated to the class of thin-film solar cells which have been under recent research work for more than two decades due to their low cost, simple preparation technology, low energy consumption, roll-to-roll manufacturing, eco-friendly, durable and light weight. Dye-sensitized solar cells (DSSCs) were fabricated using TiO2 as the photo anode and the composite of PANI and FeS2 as a counter electrode. The effect of the contents on the DSSC performance was investigated by adjusting the ratios of PANI and FeS2. It was found that the optimized DSSC efficiency of 0.9 % to 2.02% was achieved. The structure, surface morphology, elemental composition and functional groups of the PANI and FeS2 composites were characterized by XRD, SEM, TEM and FTIR analysis. This article provides an in-depth discussion on fabrication of DSSC based on polyaniline/FeS2 composite as counter electrode, operating conditions, prospective efficient materials and FTIR characteristics. From the obtained results, the composites of PANI and FeS2 counter electrode is served as an efficient, low-cost counter electrode (CE) material for dye-sensitized solar cells (DSSCs).

Improved electrochemical performance of symmetric polyaniline/activated carbon hybrid for high supercapacitance: Comparison with indirect capacitance

AbstractPolyaniline (PANI) chains doped with very small amount of Activated Carbon (AC) as an electrode material in aqueous H2SO4 electrolyte was successfully employed in this work to enhance the electrochemical capacitive properties of PANI. The aim of this research is to improve overall specific capacitance of PANI by incorporating only minute amount of AC as a PANI dopant. There are many reports available on PANI/AC but the use of such a minute amount of AC in H2SO4 electrolyte which enhances the overall specific capacity of the composite has not been reported elsewhere. An improvement in the specific capacitance from 763.44 to 897.50 F g−1 in aqueous 0.1 M H2SO4 electrolyte solution is observed by adding mere 0.04 g of AC. It is envisaged that AC enhances SO4−2 ion transportation, forwards a stable and fast surface redox reactions, hence collectively improving the overall capacitive performance of supercapacitor electrode. The charge/discharge measurements shows that AC particles stops the PANI chains degradation during charge/discharge cycle. Also, the retention rate (54%) of PANI1.0/AC0.04 indicates approximately 11% more stability than pure PANI (43%) electrode alone. It was further observed that the electrochemical impedance parameters viz., that charge transfer resistance (Rct) (0.79 Ω), response frequency (0.26 Hz), response time (3.84 s) and knee frequency (9.16 Hz) of PANI1.0/AC0.04 electrode material shows excellent performance of the PANI doped AC. Considering its high specific capacitance, low‐cost and ease of synthesis, PANI1.0/AC0.04 seems to be a promising electrode material for next generation symmetric supercapacitors.

Modified carbon cloth flexible electrode with ternary nanocomposite for high performance sediment microbial fuel cell

Sediment microbial fuel cell (SMFC) is recognized as a power generation system and has many advantages. However, it is still inappropriate for energy demands due to its operational restrictions. In this study, carbon cloth flexible electrodes modified by polyaniline-based nanocomposites were fabricated and its effect on the power output in the cell was investigated. MnO2/CNT/PANI nanocomposites are synthesized by in-situ chemical polymerization and characterized by Fourier Transform Spectroscopy, X-ray diffraction, scanning electron microscopy and transmission electron microscopy. In addition, cyclic voltammetry, linear sweep voltammetry, chronoamperometry and electrochemical impedance spectroscopy analysis were used to investigate the electrochemical behavior of the synthesized composite. The results showed that the nanocomposite-modified electrode has higher electrochemical properties than single PANI, MnO2 and CNT electrodes and their binary compounds. In addition to the electrochemical analysis, polarization tests were performed on the modified electrode in the cell that the maximum power density of the MnO2/CNT/PANI electrode 180.36 mV/m2 and the maximum voltage 670 mV were obtained and the density was about three times higher than the carbon fabric. The results indicated that using this nanocomposite, as electrodes of SMFC, was performed significantly and the development of such cells was very promising.

Energy storage and semiconducting properties of polyaniline/graphene oxide hybrid electrodes synthesized by one-pot electrochemical method

Polyaniline/graphene oxide composites are produced by the one-pot electrochemical deposition method and are used as an electrode for supercapacitor energy storage. The electrochemical tests related to the energy storage performance of the PANI/GO electrodes at different mass loading of GO are successfully studied. The biggest specific capacitance for all of the electrodes is observed at a specific current of 0.3 A g−1. Pure PANI electrode has a specific capacitance of 158.0 F g−1, a specific energy of 18.2 W h kg−1, and a corresponding specific power of 118.8 W kg−1. After the loading of graphene oxide into PANI, the best specific capacitance measured at a current density of 0.3 A g−1 is 295.9 F g−1, and the corresponding specific energy and specific power are 34.0 Wh kg−1 and 126.9 W kg−1, respectively. The PANI/GO hybrid materials also exhibit a remarkably cycling stability with a capacitance retention range of 62.3%–83.7% after 5000 charge-discharge cycles. Charge transfer resistance of the PANI electrode desreases as GO loading increases. This means that electroactive surface area of the electrode increases due to the addition of GO into PANI. The enhancement in energy storage capability is supported by the increase in electroactive surface area. The high energy storage performance and easy production of PANI/GO materials make them promising electrodes for supercapacitor devices.