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Article

Facile Synthesis of Conductive Copolymers and Its Supercapacitor Application

1
Department of Chemical Engineering and Polymer Science, Shahjalal University of Science and Technology, Sylhet 3114, Bangladesh
2
Department of Physics and Material Science, University of Memphis, Memphis, TN 38152, USA
3
High-Performance Materials Institute, FAMU-FSU College of Engineering, Tallahassee, FL 32310, USA
4
Department of Physics, Shahjalal University of Science and Technology, Sylhet 3114, Bangladesh
5
Department of Mechanical Engineering, Herff College of Engineering, University of Memphis, Memphis, TN 38152, USA
*
Author to whom correspondence should be addressed.
J. Compos. Sci. 2025, 9(5), 253; https://doi.org/10.3390/jcs9050253
Submission received: 16 February 2025 / Revised: 28 April 2025 / Accepted: 18 May 2025 / Published: 21 May 2025
(This article belongs to the Special Issue Composite Materials Containing Conjugated and Conductive Polymers)

Abstract

In this work, conductive polymers, i.e., polyaniline (PANI) and its copolymers with polypyrrole (PPy), polythiophene (PTh), and poly (3,4-ethylenedioxythiophene) (PEDOT) were synthesized following chemical oxidative polymerization methods and used in the construction of supercapacitor devices. These conductive copolymers were characterized by structural (FTIR, XRD), morphological (FESEM), electrochemical (CV and GCD), and impedance spectroscopy studies. The PANI-PPy copolymer showed higher sp. capacitance of 420 F/g and cyclic capacitive retention of 97.8% compared to the other copolymers. Additionally, Tafel extrapolation studies demonstrated that the PANI-PEDOT had the lowest corrosion rate. To further assess performance, asymmetric supercapacitor devices (ASDs) were fabricated using prepared materials. GCD analysis demonstrated that the PANI-PTh//AC device achieved a sp. capacitance of 81 F/g and power density of 550 W/kg, while the PANI-PPy//AC device exhibited a capacitance of 69 F/g. PANI-PTh//AC device shows superior performance over other electrode configurations.

1. Introduction

Supercapacitors have become a promising and popular energy storage technology, offering high-power density, rapid charge–discharge capabilities, and exceptional efficiency [1]. These energy storage devices can be fully charged/discharged within seconds, making them ideal for applications requiring quick energy delivery [2]. While their energy density is lower than that of batteries, they can provide significantly higher power output over short durations [3]. Supercapacitors can bridge the gap between lithium-ion batteries and conventional capacitor technologies by balancing power and energy density. Higher performance, life cycle, and reliability make them highly suitable for applications in electric vehicles, portable electronics, and energy backup system [4,5]. Researchers are looking for novel electrodes for developing efficient energy storage devices like supercapacitors. Intrinsically conductive polymers (ICPs) and their copolymers have gained significant attention for a wide range of applications. Among the ICPs, PANI, PPy, PTh, PEDOT, polyacetylene, and polyphenyl vinylene, have been widely investigated for use in energy storage [6]. They offer a wide variety of possible applications in rechargeable batteries, supercapacitors, fuel cells, photovoltaic cells, microwave absorption, and so on [7]. These ICPs can be prepared by chemical/electrochemical processes; however, the chemical method has the benefit of mass production and a lower cost than the electrochemical method [8,9].
Conductive homopolymers like PANI and PPy are not recommended since they have poor electrode stability and less stable molecular structure [10]. PANI experiences significant volume changes during repeated charging and discharging cycles. This leads to structural damage and shortens the lifespan of capacitive materials. Another issue that requires attention is their vulnerability to mechanical stress, which can result in problems like cracking and delamination. Researchers are increasingly focusing on improving both the mechanical and electrochemical stability of the materials. In this regard, copolymers can alleviate some of this stress due to the interactions among the conductive polymer backbones. They can also be engineered to combine other materials, resulting in cathodes that offer both high capacity and stability. The polymerization of two monomers allows for combining the superior properties of the individual monomers [11,12]. This allows for improved thermal stability and better electrochemical capacitive performance than a single component in a supercapacitor [13]. Furthermore, ICPs are frequently used as cathodes in supercapacitors due to their porous nature, which facilitates ion adsorption and reduces diffusion distances, enhancing energy storage. In batteries, the copolymer electrode can participate in energy storage through processes like proton doping and dedoping.
Xu et al. utilized an electro-polymerization process to fabricate a PEDOT/PPy copolymer to achieve a comparatively better sp. capacitance of 200 F/g along with good cyclic stability [14]. Similarly, Li et al. developed the PPy/PANI nanostructure, which demonstrated a remarkable sp. capacitance of 693 F/g at 5 mV/s and maintained outstanding capacitance retention after 1000 cycles [15]. This superior performance was attributed to the synergetic effects of both shape and composition. The polymerization of aniline and pyrrole monomers not only integrates the advantageous properties of each component but also enhances key features such as thermal stability and electrochemical capacitance, surpassing the performance of individual monomers [15,16].
Among the various doped conducting polymers, doped PANI stands out for its higher conductivity and can be easily prepared through either electrochemical or chemical synthesis methods. Hence, PANI-based copolymers are expected to provide better electrochemical performance. PANI’s chemical structure and morphology plays a crucial role in determining ion mobility and specific surface area, which subsequently impacts its redox behavior. Both PANI and PPy exhibit reversible doping and dedoping capabilities, making its copolymer viable energy storage materials. Additionally, these copolymers can enhance electrocatalytic activity for various electrochemical reactions, significantly reducing electrochemical polarization and thereby increasing battery capacity [17]. Polythiophene is valued for its simple synthesis, environmental stability, and impressive cycle durability. However, its limitations in conductivity and specific capacitance can be addressed through copolymerization with polyaniline (PANI). This approach significantly improves the overall performance of the electrode material [18]. PEDOT demonstrates excellent thermal stability, strong chemical resistance, and high electrical conductivity. However, the stability of the redox sites along the polymer backbone diminishes with repeated oxidation and reduction, ultimately reducing its cycling life. Copolymerization with polyaniline (PANI) may help address this challenge [19].
The literature reviews indicate the conductive copolymers as the prospective electrode materials for supercapacitor applications. Although some studies have been reported on conductive polymers, most of them have investigated only CV studies, and anticipated better performance of the electrode. However, applying the conductive copolymers (i.e., PANI-PPy, PANI-PTh, and PANI-PEDOT) in real device fabrication and performance tests remains unexplored.
In this work, copolymers including PANI-PPy, PANI-PTh, and PANI-PEDOT were synthesized using the chemical oxidative polymerization method and systematically characterized by electrochemical (CV, GCD), structural and morphological (FTIR, XRD, SEM) analysis. Comprehensive electrochemical studies were conducted to evaluate and compare their energy storage capacities. Lastly, a set of ASDs was fabricated with PANI-PPy, PANI-PTh, and PANI-PEDOT copolymers, and their performance was systematically assessed.

2. Materials and Methods

2.1. Materials

For the synthesis of conductive copolymers, aniline 99% (Alfa Aesar, Lancashire, UK), pyrrole 99% (Spectrochem, Mumbai, India), thiophene (Spectrochem, India), 3,4-ethylenedioxythiophene (EDOT) (TCI, Shanghai, China), ammonium persulphate (APS), and 37 wt.% of HCl (Merck, Darmstadt, Germany) were used.

2.2. Preparation of PANI, PANI-PPy, PANI-PTh, and PANI-PEDOT

For PANI, a 0.1 M aniline solution in 1 M HCl solution was prepared. APS solution was added dropwise into the solution of aniline at a controlled temperature (0 to 5 °C) with constant stirring. The temperature inside the reaction chamber was kept below 5 °C to complete the polymerization process. The reaction was terminated by adding acetone. The final products were then filtered, frequently washed with distilled water, and dried overnight in a freeze-dryer.
In the case of synthesis of the PANI-PPy, monomer aniline along with pyrrole were dissolved in 1 M of HCl. APS solution was added dropwise into the monomer solution at a controlled temperature (0–5 °C) with constant stirring. Finally, the PANI-PPy copolymer was formed following similar steps used above to synthesize the PANI.
For the synthesis of PANI-PTh and PANI-PEDOT, aniline was combined with thiophene and EDOT monomers, and the same procedures were followed as for PANI-PPy.
The synthesis of conducting copolymers can be shown schematically in Figure 1.

2.3. Methods

Formation of the ICP-based copolymers were confirmed by FTIR (Shimadzu, Kyoto, Japan). Structural patterns coming from XRD (Rigaku SmartLab, Tokyo, Japan) were analyzed to investigate the crystal structures of the copolymers. The synthesized materials’ surface morphology was examined with a FESEM (thermoscientific, Apreo 2 S, Brno, Czeck republic). The impedance properties of all the samples were characterized by an impedance analyzer (Wayne Kerr 6500B, Bognor Regis, UK).
Electrochemical investigations were performed using an electrochemical workstation (CS105). CV study was conducted for all samples at various scan rates in a 0.1 M Na2SO4 solution electrolyte. The experiments for CV and GCD were conducted in a 3-electrode system using the same method and conditions as described in the literature [20].
Specific capacitance (C) was calculated by Equation (1), energy and power density were estimated using Equation (1), Equation (2) and Equation (3), respectively.
C = ʃ I d v m υ v
where ∫I dV corresponds to the area obtained from CV curve, ΔV represents the potential difference, and m is the active mass of the material. Energy density (E) was calculated by Equation (2), where V is voltage.
E = 1 2 C V 2
Power density (P) in W/kg is calculated using Equation (3), where t is the discharge time in seconds.
P = E t

3. Results and Discussion

3.1. Structural and Morphological Properties

Figure 2 presents the FTIR spectra of the synthesized PANI, PANI-PPy, PANI-PTh, and PANI-PEDOT copolymers. The PANI demonstrated vibration bands at 3450, 2370, 1647, 1118, 798, and 507 cm−1. The vibration bands at 3450 cm−1 are assigned to N–H stretching, which indicates a characteristic peak for PANI. Spectras at 1647 cm−1 corresponded to C=C stretching of quinoid and 1118 cm−1 corresponded to the benzenoid. Additionally, the peaks at 798 cm−1 and 1296 cm−1 are attributed to the C–H bending vibration and C–N stretching, respectively, confirming the formation of PANI [20,21]. In the case of PANI-PPy, the peak at 780 cm−1 and 934 cm−1 is attributed to C–H wagging [22,23]. Here, the major peaks of PANI (1118 cm−1 and 1647 cm−1) and PPy (the band at 1565 cm−1 attributed to the pyrrole ring [22]) homopolymers shifted in the case of the PANI-PPy copolymer, indicating successful copolymer formation. He et al. also reported the change in position and intensity of the peaks as the result of the interaction between the PPy and the PANI in the copolymer formation [22]. The characteristic peaks at 1563 cm−1 correspond to the C=C stretching, whereas peaks at 1210 cm−1 and 1044 cm−1 represent C=N and C–N bonds, respectively [24]. PANI-PTh and PANI-PEDOT show almost similar characteristic peaks. The IR spectra exhibit characteristic thiophene ring stretching vibrations, along with C–C stretching, in-plane C–H vibrations, C–S stretching, and C–H out-of-plane bending vibrations, with absorption peaks observed at approximately 2368 cm−1, 1493 cm−1, 1296 cm−1, 1120 cm−1, and 820 cm−1 [25,26,27,28,29].
Figure 3 shows XRD peaks of the synthesized copolymers. X-ray peaks of PANI indicate the semicrystalline nature presenting an intensity peak at 2θ = 25.34°. Major peaks for PANI-PPy were found at 2θ = 14.84°, which is very small. On the other hand, the PANI-PTh copolymer exhibits a broad peak at 2θ = 25.28°. PANI-PEDOT shows a smaller peak at 2θ = 25.22°. From the XRD patterns, it is evident that PANI and PANI-PTh show sharp peaks or a more crystalline nature than PANI-PEDOT. While PANI-PPy shows almost no crystallinity. The peaks observed near the Bragg angle of 2θ = 20° for PANI, PANI-PPy, PANI-PTh and PANI-PEDOT suggest the ordered crystal structure due to the existence of benzenoid and quinonoid groups from PANI. The obtained results indicated that the incorporation of other polymers did not significantly disrupt the crystalline packaging of polyaniline but maintained the order of polymer matrix.
The degree of crystallinity of the polymers was calculated by dividing their integrated area of crystalline peaks by their overall integrated area, which includes both crystalline and amorphous contributions, and then multiplying the result by 100 to express it as a percentage. The crystallite sizes were calculated for all samples using the Debye–Scherrer formula. The calculated values are presented in Table 1.
The SEM analysis provides insights into the morphology of the materials. Figure 4 shows the SEM images of PANI, PANI-PPy, PANI-PTh, and PANI-PEDOT. Aggregated particles of PANI appear in Figure 4a, while Figure 4b shows the coexistence of PPy and PANI. Figure 4c indicates the coalescence of PTh and PANI, and Figure 4d proves the presence of PEDOT particles in aggregation with PANI. The comparison of the SEM images demonstrates that PANI-PPy (Figure 4b) has a relatively regular grain size and distribution compared to other synthesized materials, which contributes to better grain sizes and distribution properties. The calculated particle sizes of PANI, PANI-PPy, PANI-PTh and PANI-PEDOT are 98.48 nm, 206.27 nm, 134.52 nm and 186.54 nm, respectively.

3.2. Electrochemical Properties Analysis

Figure 5 represents the I–V curve of the synthesized copolymers, which ranges from 10 mV/s to 50 mV/s. At a lower scan rate (10 mV/s), the I–V curve exhibits a typical ideally shaped CV profile, confirming the formation of a double-layer and highlighting its key characteristics and ultrafast responsiveness. However, at higher scan rates (50 mV/s), the CV profile differs from the typical rectangular shape, suggesting a reduction in charge storage capacity.
In the case of the copolymers, the I–V curve of the PANI-PPy copolymer shows a different type of CV curve at different scan rates. Figure 5b demonstrates that CV graph changes due to the potential window as well as the incorporation of PPy in the PANI matrix. Still, PANI-PTh and PANI-PEDOT retain ideal rectangular (Figure 5c,d), similar type CV even at an elevated scan rate, which indicates its workability at comparatively high potential windows.
Sp. capacitance of the copolymers as a function of scan rates is illustrated in Figure 6a. As shown, the sp. capacitance of the copolymers reduces as the scan rates increase. The decline in capacitance is due to the presence of inner active sites that cannot effectively support redox transitions at elevated scan rates. However, all three conductive copolymers exhibit greater specific capacitance at higher scan rates (30 mV/s to 50 mV/s) compared to PANI. The PANI-PPy exhibited capacitances of 420 F/g at 10 mV/s, and 269 F/g at 50 mV/s; however, the PANI-PEDOT copolymer showed a lower sp. capacitance of 366 F/g at 10 mV/s compared to PANI-PPy. The rectangular CV curve obtained for the copolymer of PANI-PPy electrode attributed to the characteristics of double layer capacitance, which was governed through electrolyte ions (Na+ or SO42−) adsorption on its surface. This double layer can further enhance the surface area with greater electrolyte accessibility, forming a better conductive network for electrons. Moreover, the porous morphology of PANI minimizes the ion diffusion limitations which significantly contribute to store charges on the surface. While the PPy can lead to reducing the resistance to ion diffusion at the electrode–electrolyte interface because of its structural flexibility. These combined synergistic effects between PANI and PPy copolymer accelerated to achieve higher sp. capacitance over other prepared copolymers.
Figure 6b shows the energy density versus scan rate curve of different copolymers. Figure 6b illustrates that the energy density of PANI-PPy, PANI-PTh, and PANI-PEDOT copolymers decreases as the scan rate increases. In case of PANI-PPy, energy density decreases from 58 Wh/kg to 37 Wh/kg, when scan rate changes from 10 to 50 mV/s. Meanwhile, PANI-PEDOT exhibited the lowest energy density of 41 Wh/kg at 10 mV/s. However, PANI-PTh possessed an energy density of 58 Wh/kg at 10 mV/s. At 50 mV/s both PANI-PPy, and PANI-PTh have higher energy density compared to PANI.
As shown in Figure 6c, PANI-PPy exhibited the highest power density among the copolymers, outperforming PANI-PTh and PANI-PEDOT. At a scan rate of 50 mV/s, PANI-PPy achieved a peak power density of 6715 W/kg, whereas PANI displayed the lowest power density among the copolymers at the same scan rate.
Figure 6d presents the charging–discharging time of PANI, PANI-PPy, PANI-PTh, and PANI-PEDOT copolymers. PANI-PPy and PANI-PTh showed almost equal and lower charging times compared to PANI, while PANI-PEDOT exhibited the lowest charging time.
Figure 7 presents the retained capacitance of PANI-based copolymers. The PANI-PEDOT retained 96.6% of its capacitance after 100 charge–discharge cycles, while PANI-PTh maintained 98.9% capacitance retention over the same number of cycles, and PANI-PPy exhibited 97.78% capacitance retention.
Figure 8 presents the GCD profiles of the copolymers at 1 mA/cm2 current density. PANI-PPy displayed the shortest discharge time and the greatest voltage difference relative to other copolymer electrodes.
A Ragone plot is displaying specific energy (Wh/kg) on the horizontal axis and specific power (W/kg) on the vertical axis. Both axes are typically shown on a logarithmic scale, making it easier to compare the performance of different devices. Originally developed to compare battery performance, this type of plot is now widely used to assess all types of energy storage systems [30].
Figure 9 shows that the synthesized copolymers as electrodes meet almost all the conditions for the supercapacitor zone. That means PANI-PPy, PANI-PTh, and PANI-PEDOT can be used for supercapacitor applications.
For better comparison in all the performances together, Figure 10 presents comparison in performances of the synthesized PANI, PANI-PPy, PANI-PTh, and PANI-PEDOT copolymers. The figure clearly shows the better electrochemical performance of PANI-PPy copolymer compared to others.
A comparative picture of different electrodes found in the literature are shown in Table 2 and compared with the performances of the synthesized PANI-PPy, PANI-PTh, and PANI-PEDOT copolymers.
Kumar and Dhaliwal reported the sp. capacitance of PANI film as 346 F/g with the cyclic retention of 63% after 1000 cycles [31]. In another study, aniline-co-Pyrole as ANPY mixed MXene showed greater specific capacitance as 451.75 F/g and 91.8% cycle retention compared to the PANI film [35]. This can be explained due to the synergistic effect involved in the materials. MXene as the 2D transition metal carbide or nitride can provide a highly conductive layered structure with excellent surface area making suitable ion transport channels. Again, the presence of both aniline and pyrrole units can also enhance the redox activities, building more active sites for charge storage compared to pure PANI. Upon mixing with the ANPY copolymer, MXene can increase the overall conductivity and electrochemical stability of the copolymer compound. Khan et al. investigated that the mixed compound of PANI, PPy and activated carbon (AC) can provide an enhanced sp. capacitance up to 586 F/g at 1 A/g and showed a higher cycle retention after 1000 cycles as 92% [19]. Another study examined the sp. capacitance of conducting copolymer compound can be further increased with the addition of hexagonal boron nitride (h-BN). The study demonstrated that PANI-PPy-h-BN exhibited specific capacitance as 615 F/g at 10 mV/s while with the capacitance retention of 94.7% after 1000 cycles [36]. The overall comparison results suggested that the copolymer compared to single PANI can be able to act as improved energy storage performance due to the presence of enhanced redox activity, larger active sites and surface area.

3.3. Impedance Spectroscopy

The variation in dielectric properties as a function of frequency of the prepared polymer electrodes is presented in Figure 11a. Figure 11a shows the capacitance for PANI-PPy electrodes compared to other electrodes which clearly supports the better energy storage capacity of the electrode. Figure 11b presents the Cole–Cole plot of the prepared electrodes at room temperature. More electrical properties have been calculated from the figure and presented in Table 3.
Figure 11 and Table 3 show that the impedance of PANI-PPy is greater than that of the others, which clearly indicates better energy storage capacity of the PANI-PPy electrode compared to other electrodes, it also supports the findings by CV study and FESEM analysis.

3.4. Fabrication of ASDs

ASDs were assembled in this study following similar steps as described in the literature [36]. Two current collectors were used to make the hybrid supercapacitor, with aluminum foil acting as the anode and cathode current collectors. Conductive copolymers (PANI-PPy, PANI-PEDOT, PANI-PTh) and activated charcoal were used as anode and cathode in the device (Figure 12a). A separator was placed between anode and cathode, and a few drops of Na2SO4 (electrolyte solution) were carefully placed on the separator. Finally, the entire setup was charged at varying voltages and discharged through a 5 mm LED bulb (forward current of 20 mA, voltage of 2 V, and power of 0.04 W) (Figure 12b).
The schematic diagram in Figure 12c described the charge storage mechanism of the hybrid type asymmetric supercapacitor device. The negative electrode of the conducting copolymers (PANI-PPy, PANI-PEDOT or PANI-PTh) was connected to the cathode current collector of Al foil, where the positive electrode of activated charcoal connected to the anode current collector of Al foil. Na has one electron located in its outer shell which tends to excite and move from its original location. Na2SO4 breaks down into Na+ and SO4 ions at certain potential due to its electrolysis property. After power supply, the fast faradaic redox reaction occurs between the electrode–electrolyte interfaces. The SO4 ions donate one electron to the active charcoal positive electrode by oxidation in order to achieve their neutral states. On the contrary, the Na+ ions accept electrons from the negative electrode of conducting copolymers (PANI-PPy, PANI-PEDOT or PANI-PTh) by reduction process. The microporous membrane separator was attached in between the two electrode materials to avoid the issues of short circuit. Electrons move through the positive current collector to the negative current collector and try to store inside the extended surface area of conducting copolymers during the charging period. During the discharge time, electrons started returning through the current collectors and lit up the connected LED bulb as shown in Figure 12c.

Device Test

The fabricated device was charged at a constant current by DC power supply. The capacitance was calculated applying the formula provided in Equation (4).
Cp = It/mV
Cp represents sp. capacitance in F/g, I stands for current, t is discharge time in seconds, ∆V denotes voltage difference, and m is the mass loaded in the device fabrication.
Figure 13 presents the variation in the potential of the device with discharge time. The figure illustrates that the PANI-PTh//AC device exhibits longer discharge time compared to the device based on other copolymers. The PANI-PTh//AC device showed the highest sp. capacitance of 81 F/g, while the PANI-PPy//AC device exhibited a capacitance of 69 F/g. The energy and power density for the PANI-PTh//AC device were calculated as 16.2 Wh/kg and 550.2 W/kg, respectively.

4. Conclusions

In this study, PANI-based PANI-PPy, PANI-PTh, and PANI-PEDOT copolymers were synthesized and characterized thoroughly. The electrochemical analysis revealed that the formation of copolymers incorporating conductive polymers markedly improved electrochemical properties. Among these, the PANI-PPy copolymer demonstrated the maximum sp. capacitance of 420 F/g, maintaining 97.78% of its capacitance after 100 cycles of charge/discharge and achieving energy density of 58 Wh/kg. Based on these better electrochemical properties, asymmetric supercapacitor devices were fabricated using PANI-PPy, PANI-PTh, and PANI-PEDOT copolymers as electrodes. The supercapacitor performance was assessed through GCD measurements, where the PANI-PTh//AC device demonstrated comparatively higher specific capacitance of 81 F/g, with energy and power density of 16.2 Wh/kg and 550 W/kg, respectively. The device showed a coulombic efficiency of 23% and retained 48% of its initial capacitance. The PANI-PTh//AC device demonstrated higher discharge time and improved cyclic stability, the device however performed optimally at the current density of 2.5 A/g. The findings from fabricated three-electrode and two-electrode systems indicate that PANI-PPy and PANI-PTh copolymers are promising candidates for high-performance supercapacitor electrodes.

Author Contributions

Conceptualization, funding acquisition, resources, methodology, supervision M.M.R. (Md Mostafizur Rahman); investigation, formal analysis, original draft writing—I.A. and M.R.H.; XRD, FESEM, and impedance analysis, M.O.F.; writing—review and editing, F.A., N.A., M.M.R. (Mohammed Mastabur Rahman) and O.I.O. All authors have read and agreed to the published version of the manuscript.

Funding

Advanced Research in Education, the Ministry of Education, the Government of the People’s Republic of Bangladesh (Research grant 2021–2023, Project code: PS20191250).

Data Availability Statement

Machine generated raw data is available in google drive (https://drive.google.com/drive/folders/1p7xjhOXNiJcUe-03Bg9VYKDGIN1KcAVn?usp=drive_link). Detail process data can be found on request.

Conflicts of Interest

The authors declare no conflicts of interest.

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Figure 1. Steps of the synthesis of conducting copolymers.
Figure 1. Steps of the synthesis of conducting copolymers.
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Figure 2. FTIR spectra of PANI, PANI-PPy, PANI-PTh, and PANI-PEDOT.
Figure 2. FTIR spectra of PANI, PANI-PPy, PANI-PTh, and PANI-PEDOT.
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Figure 3. XRD spectra of PANI, PANI-PPy, PANI-PTh, and PANI-PEDOT.
Figure 3. XRD spectra of PANI, PANI-PPy, PANI-PTh, and PANI-PEDOT.
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Figure 4. FESEM of PANI (a), PANI-PPy (b), PANI-PEDOT (c), and PANI-PTh (d).
Figure 4. FESEM of PANI (a), PANI-PPy (b), PANI-PEDOT (c), and PANI-PTh (d).
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Figure 5. CV of PANI (a), PANI-PPy (b), PANI-PTh (c), and PANI-PEDOT (d) against Ag/AgCl ref. electrode and 1 M Na2SO4 electrolyte.
Figure 5. CV of PANI (a), PANI-PPy (b), PANI-PTh (c), and PANI-PEDOT (d) against Ag/AgCl ref. electrode and 1 M Na2SO4 electrolyte.
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Figure 6. Variation in sp. capacitance (a), energy density (b), power density (c), and charge–discharge time (d) of the copolymers with scan rates.
Figure 6. Variation in sp. capacitance (a), energy density (b), power density (c), and charge–discharge time (d) of the copolymers with scan rates.
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Figure 7. Capacitive Retention of PANI, PANI-PPy, PANI-PTh, and PANI-PEDOT at 50 mV/s after 100 cycles.
Figure 7. Capacitive Retention of PANI, PANI-PPy, PANI-PTh, and PANI-PEDOT at 50 mV/s after 100 cycles.
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Figure 8. GCD curve of the synthesized copolymers.
Figure 8. GCD curve of the synthesized copolymers.
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Figure 9. Ragone plot of PANI, PANI-PPy, PANI-PTh and PANI-PEDOT.
Figure 9. Ragone plot of PANI, PANI-PPy, PANI-PTh and PANI-PEDOT.
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Figure 10. Radar plot of PANI, PANI-PPy, PANI-PTh, and PANI-PEDOT copolymers.
Figure 10. Radar plot of PANI, PANI-PPy, PANI-PTh, and PANI-PEDOT copolymers.
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Figure 11. (a) Variation in capacitance with frequency and (b) Cole–Cole plots with interpolation.
Figure 11. (a) Variation in capacitance with frequency and (b) Cole–Cole plots with interpolation.
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Figure 12. Fabrication of an asymmetric supercapacitor (a), experimental setup to evaluate the device (b) and schematic diagram of the mechanism inside the fabricated device (c).
Figure 12. Fabrication of an asymmetric supercapacitor (a), experimental setup to evaluate the device (b) and schematic diagram of the mechanism inside the fabricated device (c).
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Figure 13. Variation in the potential of the fabricated supercapacitor device vs. discharge time.
Figure 13. Variation in the potential of the fabricated supercapacitor device vs. discharge time.
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Table 1. Crystalline size and Degree of Crystallinity of the prepared Polymers.
Table 1. Crystalline size and Degree of Crystallinity of the prepared Polymers.
SampleCu Source, λ (Å)Angle 2θ (º)Full Width with Half Maximum, β Crystalline   Sizes ,   L ( Å ) = 0.89 λ β c o s θ Degree of Crystallinity (%),
Xc = (ΣVc/VT) × 100
PANI1.5418725.341.620.91137.84
PANI-PPy1.5418714.840.463.65918.76
PANI-PTh1.5418725.280.951.889942.24
PANI-PEDOT1.5418725.220.910.7250130.73
Table 2. Comparison of PANI and its copolymers electrode’s performance.
Table 2. Comparison of PANI and its copolymers electrode’s performance.
ElectrodeSp. Capacitance, F/g Capacitance Retention/CyclesEnergy Density, Wh/kgRef.
PANI film346 63%/1000 -[31]
PANI-PPy227 --[32]
PANI-PPy/AC586 92%/10,00040 [19]
Pyrrole and 3-(4-tert-butylphenyl) Thiophene copolymer291 91%/1000 -[33]
p(Py-co-Cz)/MnOx352 99%/1000-[34]
ANPY/MXene451.75 91.8%/5000-[35]
PANI-PPy/h-BN615 94.7%/100105 [36]
PANI451 58.8%/10090 This Work
PANI-PPy420 97.78%/100 58 This Work
PANI-PTh414 98.9%/100 58 This Work
PANI-PEDOT366 96.6%/100 41 This Work
Table 3. Electrical conductivity, capacitance, reactance and impedance for prepared polymers.
Table 3. Electrical conductivity, capacitance, reactance and impedance for prepared polymers.
Sample NameElectrical Conductivity,
G (S/m)
Capacitance,
C (nF)
Reactance,
X (Ω)
Impedance,
Z (Ω)
PANI6.7123.59−200.68359.48
PANI-PPy5.70311.79−560.78661.23
PANI-PTh11.0545.99−510.79541.88
PANI-PEDOT6.6269.33−225.96377.14
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Rahman, M.M.; Alam, I.; Hossen, M.R.; Azim, F.; Anjum, N.; Faruk, M.O.; Rahman, M.M.; Okoli, O.I. Facile Synthesis of Conductive Copolymers and Its Supercapacitor Application. J. Compos. Sci. 2025, 9, 253. https://doi.org/10.3390/jcs9050253

AMA Style

Rahman MM, Alam I, Hossen MR, Azim F, Anjum N, Faruk MO, Rahman MM, Okoli OI. Facile Synthesis of Conductive Copolymers and Its Supercapacitor Application. Journal of Composites Science. 2025; 9(5):253. https://doi.org/10.3390/jcs9050253

Chicago/Turabian Style

Rahman, Md Mostafizur, Iftidul Alam, Md Rayhan Hossen, Farhan Azim, Nafiza Anjum, Muhammad Omar Faruk, Mohammed Mastabur Rahman, and Okenwa I. Okoli. 2025. "Facile Synthesis of Conductive Copolymers and Its Supercapacitor Application" Journal of Composites Science 9, no. 5: 253. https://doi.org/10.3390/jcs9050253

APA Style

Rahman, M. M., Alam, I., Hossen, M. R., Azim, F., Anjum, N., Faruk, M. O., Rahman, M. M., & Okoli, O. I. (2025). Facile Synthesis of Conductive Copolymers and Its Supercapacitor Application. Journal of Composites Science, 9(5), 253. https://doi.org/10.3390/jcs9050253

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