Polyaniline/MnO2 composite with high performance as supercapacitor electrode via pulse electrodeposition

A method of pulse electrodeposition was proposed to synthesize polyaniline (PANI)/MnO₂ composite in aniline, H₂SO₄, and MnSO₄ aqueous solution. The PANI/MnO₂ composite has rod‐like structure and MnO₂ particles are distributed on PANI uniformly. To evaluate the performance of the as‐prepared materials as supercapacitor electrodes, cyclic voltammetry, galvanostatic charge–discharge measurements, and electrochemical impedance spectroscopy were performed. The PANI/MnO₂ composite shows a higher specific capacitance (810 F g⁻¹) than pure PANI (662 F g⁻¹) at a current density of 0.5 A g⁻¹. The cycle life of the composite was also excellent. After 1,000 cycles, it maintained 86.3% of its initial capacitance. POLYM. COMPOS., 36:113–120, 2015. © 2014 Society of Plastics Engineers     

Capacitive performance of polyaniline/manganese dioxide nanofiber microsphere

This work has obtained polyaniline/manganese dioxide (PANI/MnO₂) nanofibers microsphere by interfacial chemical synthesis with 4‐amino‐thiophenol (4‐ATP) as the structure‐directing agent on the Au substrate. The cyclic voltammograms, galvanostatic charge–discharge, and electrochemical impedance spectroscopy were used to determine their capacitive performance. Powder X‐ray diffraction, thermogravimetry and differential scanning calorimetry, Fourier transformed infrared spectroscopy, Brunauer–Emmett–Teller surface area measurements, and scanning electron microscope were performed for physical and chemical characterization. The effect of 4‐ATP and acids on the capacitive performance of PANI/MnO₂ nanofibers microsphere was elucidated. The as‐prepared PANI/MnO₂ was nanofiber about 30 nm diameters, and they further self‐assembled into sphere. Its specific capacitance is up to 765 F g^?1 at 1.0 mA cm^?2 in 1.0M Na₂SO₄ solution. And it shows a high stability with a capacitance fade of only 14.9% after 400 charge–discharge cycles. The symmetric capacitor of PANI/MnO₂ (PM10+)/PANI/MnO₂ (PM10?) is assembled in 1.0M Na₂SO₄ solution, and its capacitive performance is compared with that of PANI (+)/PANI (?) and MnO₂ (+)/MnO₂ (?). © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40575.     

Controllable synthesis of MnO2/polyaniline nanocomposite and its electrochemical capacitive property

Polyaniline (PANI) and MnO₂/PANI composites are simply fabricated by one-step interfacial polymerization. The morphologies and components of MnO₂/PANI composites are modulated by changing the pH of the solution. Formation procedure and capacitive property of the products are investigated by XRD, FTIR, TEM, and electrochemical techniques. We demonstrate that MnO₂ as an intermedia material plays a key role in the formation of sample structures. The MnO₂/PANI composites exhibit good cycling stability as well as a high capacitance close to 207 F g⁻¹. Samples fabricated with the facile one-step method are also expected to be adopted in other field such as catalysis, lithium ion battery, and biosensor.     

Electrospun polyaniline nanofibers web electrodes for supercapacitors

Polyaniline nanofibers (PANI‐NFs) web are fabricated by electrospinning and used as electrode materials for supercapacitors. Field‐emission scanning electron microscope micrographs reveal nanofibers web were made up of high aspect ratio (>50) nanofibers of length ～30 μm and average diameter ～200 nm. Their electrochemical performance in aqueous (1M H₂SO₄ and Na₂SO₄) and organic (1M LiClO₄ in propylene carbonate) electrolytes is compared with PANI powder prepared by in situ chemical oxidative polymerization of aniline. The electrochemical properties of PANI‐NFs web and PANI powder are studied using cyclic voltammetry, galvanostatic charge/discharge, and electrochemical impedance spectroscopy. PANI‐NFs web show higher specific capacitance (～267 F g^?1) than chemically synthesized PANI powder (～208 F g^?1) in 1M H₂SO₄. Further, PANI‐NFs web demonstrated very stable and superior performance than its counterpart due to interconnected fibrous morphology facilitating the faster Faradic reaction toward electrolyte and delivered specific capacitance ～230 F g^?1 at 1000th cycle. Capacitance retention of PANI‐NFs web (86%) is higher than that observed for PANI powder (48%) indicating the feasibility of electro spun PANI‐NFs web as superior electrode materials for supercapacitors. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Copper chloride‐doped polyaniline/multiwalled carbon nanotubes nanocomposites: Superior electrode material for supercapacitor applications

In this study, copper chloride (CuCl₂)‐doped polyaniline (PANI)/multiwalled carbon nanotubes (MWCNTs) nanocomposite (PANI C2 CNT), CuCl₂‐doped PANI (PANI C2) and pure PANI was synthesized by in situ oxidative polymerization method, using ammonium peroxodisulfate as oxidant in HCl medium. These composites were investigated as electrode materials for supercapacitors. The interaction of metal cation (Cu²⁺) with PANI was confirmed by Fourier transform infrared spectroscopy. The morphology of the composites was characterized by field‐emission scanning electron microscopy and high‐resolution transmission electron microscopy analysis. Electrochemical characterizations of the materials were carried out by three electrode probe method, where platinum and saturated standard calomel electrode were used as counter and reference electrode, respectively. 1 M KCl solution was used as electrolyte for all the electrochemical characterizations. The transition metal ion doping enhanced the electrochemical properties of the conducting polymer. Among all the composites, CuCl₂‐doped PANI/MWCNT showed highest specific capacitance value of 724 F/g at 10 mV s⁻¹ scan rate. The Nyquist plot of the polymeric materials showed low equivalent series resistance of the electrode materials. Thermal stability of the composites was examined by thermogravimetric analysis.POLYM. COMPOS., 2013. © 2013 Society of Plastics Engineers     

Nanosheet-like MoO3 and conductive PANI electrodeposited on flexible carbon cloth for self-supported solid-state supercapacitor electrode

In this paper, uniformly transition metal oxide (MoO₃) nanosheets were electrochemically deposited on flexible carbon cloth (CC), and then conductive polyaniline (PANI) was orderly wrapped around their surface by electrochemical polymerization. The morphology and structure of as-obtained self-supported PANI/MoO₃/CC electrode were investigated by FTIR, X-ray diffraction, Raman, scanning electron microscope (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy measurements in detail. Among all PANI/MoO₃/CC electrode, the self-supported PMC-3 (deposition time of 300 s) has high specific capacitance of 841.6 F g⁻¹ at current density of 0.5 A g⁻¹ in the three-electrode system, having specific capacitance of 595.7 F g⁻¹ even at 10 A g⁻¹. Novelty, the as-assembled symmetrical capacitor is flexible and convenient with power density of 199.93 W kg⁻¹ at the energy density of 9.69 Wh kg⁻¹ and the energy density of 3.88 Wh kg⁻¹ at power density of 4000 W kg⁻¹. Thus, the electrochemical properties of the self-supported PANI/MoO₃/CC electrode were significantly improved, and the self-supported electrodes are more competitive than other materials in practical application of clean energy storage systems.     

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     

Polyaniline grafted chitosan/GO-CNT/Fe3O4 nanocomposite as a superior electrode material for supercapacitor application

Developing appropriate stable electroactive electrode materials for supercapacitor application is the challenging issue, which attracts enormous attention in recent decades. In this regard, Fe₃O₄ nanoparticles are firstly synthesized on chitosan/graphene oxide-multiwall carbon nanotubes (CS/GM/Fe₃O₄). Then, polyaniline (PANI) is grafted on it via in situ chemical polymerization and named as CS/GM/Fe₃O₄/PANI. The as-prepared nanocomposites are characterized by Field emission scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and energy dispersive X-ray spectroscopy. The capacitive properties of the electrodes are investigated in a three electrode configuration in 0.5 M Na₂SO₄ electrolyte by various electrochemical techniques. The specific capacitance of CS/GM/Fe₃O₄/PANI electrode is 1513.4 Fg⁻¹ at 4 Ag⁻¹ which is 1.9 times higher than that of CS/GM/Fe₃O₄ (800 Fg⁻¹). Meanwhile, the electrodes exhibit appropriate cycle life along with 99.8% and 93.95% specific capacitance at 100 Ag⁻¹ for chitosan/GO-CNT/Fe₃O₄ and polyaniline grafted chitosan/GO-CNT/Fe₃O₄, respectively.     

Enhanced performance by polyaniline/tailored carbon nanotubes composite as supercapacitor electrode material

Polyaniline/tailored carbon nanotubes composite (PANI/TCN) synthesized via situ polymerization of aniline monomer in the presence of tailored carbon nanotubes (TCN) is reported as electrode material for supercapacitors. The morphology, structure, and thermostability of the composite were characterized by scanning electron microscope, Fourier transform infrared, and thermogravimetric analysis. The electrochemical property of the resulting material was systematically studied using cyclic voltammetry and galvanostatic charge–discharge. The results show that the short rod‐like PANI dispersed well in the TCN with three‐dimensional network structure. The as‐prepared composite shows high specific capacitance and good cycling stability. A specific capacitance of 373.5 F g^?1 at a current density of 0.5 A g^?1 was achieved, which is much higher than that of pure PANI (324 F g^?1). Meanwhile, the composite retains 61.7% capacity after 1000 cycles at a scan rate of 50 mV s^?1. The enhanced specific capacitance and capacity retention indicates the potential of composite as a promising supercapacitor electrode material. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2014 , 131, 39971.     

Hydrothermal synthesis and characterization studies of α-Fe2O3/MnO2 nanocomposites for energy storage supercapacitor application

In this present study, semiconductor magnetic α-Fe₂O₃/MnO₂ nanocomposites (NCs) were prepared by a facile hydrothermal (HT) method. The crystallographic structure, morphology, chemical configuration and magnetic features were analysed by X-ray powder diffraction (XRD), high resolution scanning electron microscope (HR-SEM), energy dispersive X-ray analysis (EDX), transmission electron microscope (TEM), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS) and vibrating sample magnetometer (VSM) analyses. The as-prepared NCs were used as an electrode in energy storing supercapacitor was systematically examined. The electrochemical deeds of α-Fe₂O₃/MnO₂ NCs was analysed by cyclic voltammetry (C–V) and galvanostatic charge–discharge (GCD) tests. The CV analysis of the NCs electrode showed a distinctive pseudocapacitive behaviour in 1 M KOH solution. The NCs electrode reveals enhanced specific capacitance compared to plain α-Fe₂O₃ and MnO₂ nanoparticles (NPs) and generates high specific capacitance of 216.35 Fg⁻¹. Pseudocapacitor obtains of energy density 135.42 Wh kg⁻¹ at power density of 6.399 kW kg⁻¹, indicating the as-prepared α-Fe₂O₃/MnO₂ NCs shows noteworthy high-energy, specific capacitance, power densities and long-standing cyclic stability with 89.2% of preliminary capacitance reserved at 1A g⁻¹ after 10000 cycles in judgement with the pure α-Fe₂O₃ and MnO₂ NPs electrode. The α-Fe₂O₃/MnO₂ NCs electrode having noteworthy electrochemical characteristics performance renders promising applications in energy storing systems.     

Solid‐state synthesis and characterization of polyaniline/nano‐TiO2 composite

Polyaniline/nano‐TiO₂ composites with the content of nano‐TiO₂ varying from 6.2 wt % to 24.1 wt % were prepared by using solid‐state synthesis method at room temperature. The structure and morphology of the composites were characterized by the Fourier transform infrared (FTIR) spectra, ultraviolet‐visible (UV–vis) absorption spectra, X‐ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The electrochemical performances of the composites were investigated by galvanostatic charge–discharge measurement, cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). The results from FTIR and UV–vis spectra showed that the composites displayed higher oxidation and doping degree than pure PANI. The XRD and morphological studies revealed that the inclusion of nano‐TiO₂ particles hampered the crystallization of PANI chains in composites, and the composites exhibited mixed particles from free PANI particles and the nano‐TiO₂ entrapped PANI particles. The galvanostatic charge–discharge measurements indicated that the PANI/nano‐TiO₂ composites had higher specific capacitances than PANI. The composite with 6.2 wt % TiO₂ had the highest specific capacitance among the composites. The further electrochemical tests on the composite electrode with 6.2 wt % TiO₂ showed that the composite displayed an ideal capacitive behavior and good rate ability. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Preparation and characterization of manganese oxide/CNT composites as supercapacitive materials

Manganese oxide was synthesized and dispersed on carbon nanotube (CNT) matrix by thermally decomposing manganese nitrates. CNTs used in this paper were grown directly on graphite disk by chemical vapor deposition technique. The capacitive behavior of manganese oxide/CNT composites was investigated by cyclic voltammetry and galvanostatic charge–discharge method in 1 M Na₂SO₄ aqueous solutions. When the loading mass of MnO₂ is 36.9 μg cm^− 2, the specific capacitance of manganese oxide/CNT composite (based on MnO₂) at the charge–discharge current density of 1 mA cm^− 2 equals 568 F g^− 1. Additionally, excellent charge–discharge cycle stability (ca. 88% value of specific capacitance remained after 2500 charge–discharge cycles) and power characteristics of the manganese oxide/CNT composite electrode can be observed. The effect of loading mass of MnO₂ on specific capacitance of the electrode has also been investigated.     

Influences of graphene oxide support on the electrochemical performances of graphene oxide-MnO2 nanocomposites

MnO₂ supported on graphene oxide (GO) made from different graphite materials has been synthesized and further investigated as electrode materials for supercapacitors. The structure and morphology of MnO₂-GO nanocomposites are characterized by X-ray diffraction, X-ray photoemission spectroscopy, scanning electron microscopy, transmission electron microscopy, Raman spectroscopy, and Nitrogen adsorption-desorption. As demonstrated, the GO fabricated from commercial expanded graphite (denoted as GO(1)) possesses more functional groups and larger interplane gap compared to the GO from commercial graphite powder (denoted as GO(2)). The surface area and functionalities of GO have significant effects on the morphology and electrochemical activity of MnO₂, which lead to the fact that the loading amount of MnO₂ on GO(1) is much higher than that on GO(2). Elemental analysis performed via inductively coupled plasma optical emission spectroscopy confirmed higher amounts of MnO₂ loading on GO(1). As the electrode of supercapacitor, MnO₂-GO(1) nanocomposites show larger capacitance (307.7 F g^-1) and better electrochemical activity than MnO₂-GO(2) possibly due to the high loading, good uniformity, and homogeneous distribution of MnO₂ on GO(1) support.     

In situ doping of PANI nanocomposites by gold nanoparticles for high‐performance electrochemical energy storage

Polyaniline (PANI) in situ doped with gold nanoparticles (Au/PANI) is synthesized by oxidative polymerization as electrode material for supercapacitor. The morphologies and structure of the obtained products are characterized by transmission electron microscopy, scanning electron microscopy, and Fourier transform infrared spectroscopy; and electrochemical behaviors were measured by electrochemical workstation. The results show that the nanocomposites of Au/PANI are fabricated with gold nanoparticles (nano‐Au) dispersed well in PANI bulk; and specific capacitance (SC) and rate ability of Au/PANI are improved compared to the pristine PANI due to the introduction of nano‐Au. With nano‐Au content increasing, SC first increase and then decrease and the maximum SC of Au/PANI nanocomposite is up to 462 F g^?1 with the nano‐Au content of 1.64 wt %. Finally, both asymmetric and symmetric supercapacitor devices are assembled, exhibiting high energy densities of 8.95 and 4.17 Wh kg^?1, respectively. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 45309.     

Polypyrrole/MnO2 composites and their enhanced electrochemical capacitance

The composites of polypyrrole (PPY) and MnO₂ have been prepared through chemical oxidation of pyrrole monomer and MnO₂ suspension with ammonium peroxysulfate at low temperature. The morphology and structure of materials were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), Transmission electron microscopy (TEM), thermal gravity analysis ‐ differential thermal gravity (TG‐DTG), and X‐ray diffraction (XRD) measurements. The electrochemical properties of the composite were investigated by galvanostatic charge–discharge and electrochemical impedance spectroscopy. The specific capacitance of the composite electrode is 352.8 F/g at a current of 8 mA/cm² in Na₂SO₄ electrolyte of 0.5 mol/L, which is much higher than that of 246.2 F/g and 103.5 F/g of PPY and MnO₂, respectively. A convenient and effective technique has been developed to fabricate composite materials of PPY and MnO₂ promising for designing new capacitors. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

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     

The additive-free electrode based on the layered MnO2 nanoflowers/reduced,graphene oxide film for high performance supercapacitor

The MnO₂ nanoflowers/reduced graphene oxide composite is coated on a nickel foam substrate (denoted as MnO₂ NF/RGO @ Ni foam) via the layer by layer (LBL) self-assembly technology without any polymer additive, following the soft chemical reduction. The layered MnO₂ NF/RGO composite is uniformly anchored on the Ni foam skeleton to form the 3D porous framework, and the interlayers have access to lots of ions channels to improve the electron transfer and diffusion. This special construction of 3D porous structure is beneficial to the enhancement of electrochemical property. The specific capacitance is up to 246 F g⁻¹ under the current density of 0.5 A g⁻¹. After 1000 cycles, it can retain about 93%, exhibiting excellent cycle stability. The electrochemical impedance spectroscopy measurements confirm that MnO₂ NF/RGO @ Ni foam electrode has lower R_ESR and R_CT values when compared to MnO₂ @ Ni foam and RGO @ Ni foam. This study opens a new door to the preparation of composite electrodes for high performance supercapacitor.     

Cauliflower-like poly(3,4-ethylenedioxythipohene)/nanocrystalline cellulose/manganese oxide ternary nanocomposite for supercapacitor

A cauliflower-like ternary nanocomposite of poly(3,4-ethylenedioxythipohene)/nanocrystalline cellulose/manganese oxide (PEDOT/NCC/MnO₂) was synthesized using one-step electropolymerization technique. The effect of manganese (Mn) concentration on the supercapacitive performance was investigated. The structural and morphology studies were conducted using field emission scanning electron microscope, Fourier transform infrared spectroscopy, Raman spectroscopy, and X-ray diffraction. The morphology of ternary nanocomposite at an optimized concentration of Mn resembles the cauliflower-like structure. The two-electrode electrochemical analysis of a ternary nanocomposite PEDOT/NCC/MnO₂ exhibited a higher specific capacitance of 144.69 F/g at 25 mV/s in 1.0 M potassium chloride compared to PEDOT/NCC(63.57 F/g). PEDOT/NCC/MnO₂ ternary nanocomposite was able to deliver a specific power of 494.9 W/kg and 10.3 Wh/kg of specific energy at 1 A g⁻¹ and retained 83% of initial capacitance after 2,000 cycles. These promising results from the incorporation of Mn displayed great prospective in developing PEDOT/NCC/MnO₂ as an electrode material for supercapacitor.     

Modified Carbon Anode by MWCNTs/PANI Used in Marine Sediment Microbial Fuel Cell and its Electrochemical Performance

Improving the performance of anode is a crucial step for increasing power output of marine sediment microbial fuel cells (SMFCs). A multi‐walled carbon nanotube/polyaniline (MWCNTs/PANI) modified anode was prepared by the way of electrochemical deposition and its electrochemical performance is investigated in this paper. Result shows that the wettability of carbon felt becomes better and the number of bacteria (9.52 × 10¹² m⁻²) on anode biofilm is increased respectively, which is 9 times higher than that of the unmodified. The anti‐polarization ability of the modified anode increases significantly and its kinetic activity of electron transfer increases 4 times. Its exchange current density is 3.62 × 10⁻⁵ A cm⁻². The maximum power density of the modified SMFC reaches 527.0 mW m⁻², which is 4 times higher than that of the unmodified one. Finally, a novel molecular synergistic mechanisms for the enhanced SMFC is also presented, based on the higher bacteria number, the capacitive performance of PANI, the hydrogen bond interaction and higher conductivity of MWCNTs. This excellent electrochemical performance makes the MWCNTs/PANI composite be a potential choice for higher output SMFC.     

Preparation and electrochemical properties of polyaniline/α‐RuCl3.xH2O composites for supercapacitor

Polyaniline/α‐RuCl₃.xH₂O composites were successfully synthesized by an in‐situ chemical polymerization and employed as new electrode materials in supercapacitors. The synthesized composites were characterized physically by scanning electronic microscope (SEM). The electrochemical capacitance performance of these composites was investigated by cyclic voltammetry, galvanostatic charge–discharge tests and AC impedance spectroscopy with a three‐electrode system in 1 mol l⁻¹ NaNO₃ aqueous solution electrolyte. The polyaniline/α‐RuCl₃.xH₂O composites electrodes showed much higher specific capacitance, better power characteristics and were more promising for application in capacitor than pure polyaniline electrode. The effect and role of α‐RuCl₃.xH₂O in the composite electrode were also discussed in detail. POLYM. COMPOS., 34:2142–2147, 2013. © 2013 Society of Plastics Engineers