Electrochemical fabrication of polyaniline/MnO2/graphite felt as free‐standing,flexible electrode for supercapacitors

Polyaniline/MnO₂/graphite felt (PMGF) composite, which can be used as a novel free‐standing, flexible electrode for supercapacitors, was fabricated via a facile electrochemical method. Polyaniline/graphite felt (PANI/GF) electrode was prepared by electropolymerization of PANI onto the GF. Subsequently, manganese dioxide (MnO₂) was electrodeposited on the surface of the PANI/GF electrode to prepare PMGF electrode. The microstructure and morphology of the as‐prepared samples were characterized by Fourier transform infrared spectra, X‐ray diffraction, scanning electron microscopy, and transmission electron microscopy. Specific surface area was examined using N₂ adsorption/desorption test. Cyclic voltammogram, chronopotentiometry techniques and electrochemical impedance spectroscopy were introduced to investigate the electrochemical performance of the composites. The PMGF electrode exhibited specific capacitance as high as about 630 F g⁻¹ at the current density of 0.5 A g⁻¹, which is much higher than that of PANI/MnO₂ composites reported previously. The high specific capacitance of PMGF may be attributed to the fact that the porous GF is a good conductive matrix for the dispersion of PANI/MnO₂ and it can facilitate easy access of electrolytes to the electrode, which results in enhancement of the electrochemical performance of the composite. Moreover, the specific capacitance of PMGF is much larger than that of MnO₂/GF (MGF), which may be ascribed to the participant of PANI, which contributes additional pseudocapacitance and electron transport path. POLYM. COMPOS., 34:819–824, 2013. © 2013 Society of Plastics Engineers     

Flexible electrodes based on polypyrrole/manganese dioxide/polypropylene fibrous membrane composite for supercapacitor

The composites of polypyrrole/manganese dioxide/polypropylene fibrous films (PPy/MnO₂/PPF) have been prepared in situ through chemical oxidation polymerization by using the mixture of FeCl₃·6H₂O and MnO₂ adsorbed on PPF as oxidant in the atmosphere of pyrrole vapor at room temperature. The morphologies and structures of the composites are investigated by using scanning electron microscope and X-ray diffraction spectroscopy. The properties of the capacitor cells assembled by the composites of PPy/MnO₂/PPF are evaluated by cyclic voltammetry, galvanostatic charge/discharge and electrochemical impedance spectroscopy methods. The results reveal that the morphologies, conductivities and capacitance performance of the composites are influenced strongly by the content of MnO₂ in the solution of oxidant. The capacitors assembled by PPy/MnO₂/PPF exhibit the property of quick charge/discharge, and the highest specific capacitance of about 110 F g⁻¹ is obtained when the PPy/MnO₂ content in the composite is about 17.4%.     

Enhanced electrochemical stability and charge storage of MnO2/carbon nanotubes composite modified by polyaniline coating layer in acidic electrolytes

Manganese dioxide/multiwalled carbon nanotubes (MnO₂/MWCNTs) were synthesized by chemically depositing MnO₂ onto the surface of MWCNTs wrapped with poly(sodium-p-styrenesulfonate). Then, polyaniline (PANI) with good supercapacitive performance was further coated onto the MnO₂/MWCNTs composite to form PANI/MnO₂/MWCNTs organic-inorganic hybrid nanoarchitecture. Electrochemical performance of the hybrid in Na₂SO₄-H₂SO₄ mixed acidic electrolytes was evaluated by cyclic voltammetry (CV) and chronopotentiometry (CP) in detail. Comparative electrochemical tests revealed that the hybrid nanoarchitecture could operate in the acidic medium due to the protective modification of PANI coating layer onto the MnO₂/MWCNTs composite, and that its electrochemical behavior was greatly dependent upon the concentration of protons in the acidic electrolytes. Here, PANI not only served as a physical barrier to restrain the underlying MnO₂/MWCNTs composite from reductive-dissolution process so as to make the novel ternary hybrid material work in acidic medium to enhance the utilization of manganese oxide as much as possible, but also was another electroactive material for energy storage in the acidic mixed electrolytes. It was due to the existence of PNAI layer that an even larger specific capacitance (SC) of 384 F g⁻¹ and a much better SC retention of 79.9% over 1000 continuous charge/discharge cycles than those for the MnO₂/MWCNTs nanocomposite were delivered for the hybrid in the optimum 0.5 M Na₂SO₄-0.5 M H₂SO₄ mixed acidic electrolyte.     

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     

Thermoelectric properties of Ca0.8Dy0.2MnO3 synthesized by solution combustion process

High-quality Ca_0.8Dy_0.2MnO₃ nano-powders were synthesized by the solution combustion process. The size of the synthesized Ca_0.8Dy_0.2MnO₃ powders was approximately 23 nm. The green pellets were sintered at 1150-1300°C at a step size of 50°C. Sintered Ca_0.8Dy_0.2MnO₃ bodies crystallized in the perovskite structure with an orthorhombic symmetry. The sintering temperature did not affect the Seebeck coefficient, but significantly affected the electrical conductivity. The electrical conductivity of Ca_0.8Dy_0.2MnO₃ increased with increasing temperature, indicating a semiconducting behavior. The absolute value of the Seebeck coefficient gradually increased with an increase in temperature. The highest power factor (3.7 × 10^-5 Wm^-1 K^-2 at 800°C) was obtained for Ca_0.8Dy_0.2MnO₃ sintered at 1,250°C. In this study, we investigated the microstructure and thermoelectric properties of Ca_0.8Dy_0.2MnO₃, depending on sintering temperature.     

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.     

Mesoporous polyaniline or polypyrrole/anatase TiO2 nanocomposite as anode materials for lithium-ion batteries

A functional composite as anode materials for lithium-ion batteries, which contains highly dispersed TiO₂ nanocrystals in polyaniline matrix and well-defined mesopores, is fabricated by employing a novel one-step approach. The as-prepared mesoporous polyaniline/anatase TiO₂ nanocomposite has a high specific surface area of 224 m² g⁻¹ and a predominant pore size of 3.6 nm. The electrochemical performance of the as-prepared composite as anode material is investigated by cyclic voltammograms and galvanostatic method. The results demonstrate that the polyaniline/anatase nanocomposite provides larger initial discharge capacity of 233 mAh g⁻¹ and good cycle stability at the high current density of 2000 mA g⁻¹. After 70th cycles, the discharge capacity is maintained at 140 mAh g⁻¹. The excellent electrochemical performance of the polyaniline/TiO₂ nanocomposite is mainly attributed to its special structure. Furthermore, it is accessible to extend the novel strategy to other polymer/TiO₂ composites, and the mesoporous polypyrrole/anatase TiO₂ is also successfully fabricated.     

Encapsulation of manganese oxides nanocrystals in electrospun carbon nanofibers as free-standing electrode for supercapacitors

Flexible composites with manganese oxides (MnO_x) nanocrystals encapsulated in electropun carbon nanofibers were successfully fabricated via a simple and practical combination of electrospinning and carbonization process. The as-formed MnO_x/carbon nanofibers composites have a rough surface with MnO_x nanoparticles well embedded in the carbon nanofibers backbones. When used as electrodes for supercapacitor, the resulting MnO_x/carbon nanofiber composites exhibit good electrochemical performance with a specific capacitance of 174.8 F g⁻¹ at 2 mV s⁻¹ in 0.5 M Na₂SO₄ electrolyte, a good rate capability at high current density and long-term cycling stability. It is expected that such freestanding composites could be promising electrodes for high-performance supercapacitors.     

Photocatalytic reduction synthesis of SrTiO3-graphene nanocomposites and their enhanced photocatalytic activity

SrTiO₃-graphene nanocomposites were prepared via photocatalytic reduction of graphene oxide by UV light-irradiated SrTiO₃ nanoparticles. Fourier transformed infrared spectroscopy analysis indicates that graphene oxide is reduced into graphene. Transmission electron microscope observation shows that SrTiO₃ nanoparticles are well assembled onto graphene sheets. The photocatalytic activity of as-prepared SrTiO₃-graphene composites was evaluated by the degradation of acid orange 7 (AO7) under a 254-nm UV irradiation, revealing that the composites exhibit significantly enhanced photocatalytic activity compared to the bare SrTiO₃ nanoparticles. This can be explained by the fact that photogenerated electrons are captured by graphene, leading to an increased separation and availability of electrons and holes for the photocatalytic reaction. Hydroxyl (·OH) radicals were detected by the photoluminescence technique using terephthalic acid as a probe molecule and were found to be produced over the irradiated SrTiO₃ nanoparticles and SrTiO₃-graphene composites; especially, an enhanced yield is observed for the latter. The influence of ethanol, KI, and N₂ on the photocatalytic efficiency was also investigated. Based on the experimental results, ·OH, h⁺, and H₂O₂ are suggested to be the main active species in the photocatalytic degradation of AO7 by SrTiO₃-graphene composites.

PACS

61.46. + w; 78.67.Bf; 78.66.Sq     

Multiwall carbon nanotube supported poly(3,4-ethylenedioxythiophene)/manganese oxide nano-composite electrode for super-capacitors

MWCNT-PSS/PEDOT/MnO₂ nano-composite electrodes were fabricated by generating pseudo-capacitive poly(3,4-ethylenedioxythiophene) (PEDOT)/MnO₂ nano-structures on poly(styrene sulfonate) (PSS) dispersed multiwalled carbon nanotubes (MWCNTs). PSS dispersed MWCNTs (MWCNT-PSS) facilitated the growth of PEDOT and MnO₂ into nano-rods with large active surface area and good electrical conductivity. The ternary MWCNT-PSS/PEDOT/MnO₂ nano-composite electrode was studied for the application in super-capacitors, and exhibited excellent capacitive behavior between −0.2 V and 0.8 V (vs. saturated Ag/AgCl electrode) with high reversibility. Specific capacitance of the nano-composite electrode was found as high as 375 F g⁻¹. In contrast, specific capacitance of MWCNT-PSS/MnO₂ and MWCNT-PSS nano-composite electrodes is 175 F g⁻¹ and 15 F g⁻¹, respectively. Based on cyclic voltammetric studies and cycle-life tests, the MWCNT-PSS/PEDOT/MnO₂ nano-composite electrode gave a highly stable and reversible performance up to 2000 cycles. Our studies demonstrate that the synergistic combination of MWCNT-PSS, PEDOT and MnO₂ has advantages over the sum of the individual components.     

Enhanced NO2 gas sensor device based on supramolecularly assembled polyaniline/silver oxide/graphene oxide composites

Herein, we report a successful synthesis of supramolecularly assembled polyaniline/silver oxide/graphene oxide composite (PANI/Ag₂O/GO) for enhanced NO₂ gas sensing application. The PANI/Ag₂O/GO composite was synthesized by facile stirring followed by an ultrasonication process. The prepared material was characterized by different techniques such as x-ray diffraction, field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy and Raman-scattering spectroscopy. The detailed analysis revealed that the average crystallite sizes of PANI/Ag₂O and PANI/Ag₂O/GO composites were found to be 37.37 nm and 41.55 nm, respectively. FESEM and TEM analysis showed coral-like rough-surfaced and extensively agglomerated morphology for PANI and ultrathin flexible sheet-like morphology for GO. Ag₂O nanoparticles with diameters 20–30 nm were well incorporated in the GO sheets and PANI matrix in the case of PANI/Ag₂O/GO composites. The synthesized materials were used to make resistive sensor devices that had a high response to NO₂ gas. The fabricated sensors were examined at various temperatures to obtain the optimal sensing temperature. The fabricated NO₂ gas sensor device based on PANI/Ag₂O/GO composite exhibited a highest sensitivity of 5.85 for 25 ppm at an optimized temperature (100 °C) as compared to the pure PANI (2.5) and PANI/Ag₂O composite (3.25). Further, the fabricated sensor device based on PANI/Ag₂O/GO composite was also examined at different NO₂ gas concentrations.     

Flower-like ZnO-Ag2O composites: precipitation synthesis and photocatalytic activity

Ag₂O-decorated flower-like ZnO composites were fabricated through a chemical precipitation process. X-ray diffraction analysis confirms the co-existence of cubic Ag₂O and wurtzite ZnO phases. Scanning electron microscopy images reveal Ag₂O nanoparticles located on the rough surface of ZnO flowers. The photocatalytic activities of the composites with various mole ratios were evaluated by the degradation of methyl orange (MO) under ultraviolet irradiation, which confirms that the composite shows superior activity to that of pure ZnO and Ag₂O. The improvement can be ascribed to the deposited Ag₂O forming the p-n junction at the interface of ZnO and Ag₂O, resulting in the transfer of photocarriers and suppressing the electron–hole recombination rate.     

Simple fabrication of N-doped mesoporous TiO2 nanorods with the enhanced visible light photocatalytic activity

N-doped mesoporous TiO₂ nanorods were fabricated by a modified and facile sol–gel approach without any templates. Ammonium nitrate was used as a raw source of N dopants, which could produce a lot of gasses such as N₂, NO₂, and H₂O in the process of heating samples. These gasses were proved to be vitally important to form the special mesoporous structure. The samples were characterized by the powder X-ray diffraction, X-ray photoelectron spectrometer, nitrogen adsorption isotherms, scanning electron microscopy, transmission electron microscopy, and UV-visible absorption spectra. The average length and the cross section diameter of the as-prepared samples were ca. 1.5 μm and ca. 80 nm, respectively. The photocatalytic activity was evaluated by photodegradation of methylene blue (MB) in aqueous solution. The N-doped mesoporous TiO₂ nanorods showed an excellent photocatalytic activity, which may be attributed to the enlarged surface area (106.4 m² g^-1) and the narrowed band gap (2.05 eV). Besides, the rod-like photocatalyst was found to be easy to recycle.     

Rational design of electrochemically active polymorphic MnOx/rGO composites for Li+-rechargeable battery electrodes

Electrochemical behavior of different MnO_x @reduced graphene oxide (rGO) composites derived from a MnO₂/GO template are thoroughly investigated. As-prepared MnO₂/GO mixture is gradually converted to MnO₂/rGO and finally to Mn₃O₄/rGO composites under controlled post annealing conditions. The semispherical Mn₃O₄ crystalline compound anchored composite exhibits stable electrode performances, including both the Li⁺ anode and the Li⁺-air cathode catalyst, induced by the electrochemically favorable composite with an effective large contact area between the active materials and the electronic conductive rGO. It is such a meaningful to suggest the facile and controllable synthetic procedures for obtaining Li-rechargeable electrodes with a MnO_x nanoparticle-incorporated composites for the highly reactive lithiation/delithiation electrochemical reactions.     

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     

A novel method to prepare two-dimensional manganese dioxide and its potential application as a sensor to detect hydrogen peroxide and L-ascorbic acid in water

A sensitive sensor for the rapid detection of L-ascorbic acid (AA) and hydrogen peroxide (H₂O₂) was fabricated with two-dimensional MnO₂ nanoparticles. The two-dimensional MnO₂ nanoparticles are favorable for fabrication of sensors, due to its enhanced electrochemical property. The two-dimensional MnO₂ nanoparticles were prepared in two different types of stirred media mills. The morphological characterization was conducted by transmission electron microscopy (TEM), high resolution transmission electron microscopy (HR-TEM). The crystal structure of MnO₂ nanoparticles was characterized by X-Ray diffraction analysis. The sensor based on MnO₂ nanoparticles exhibits high sensitivity due to the enhanced oxidation at two-dimensional MnO₂ nanoparticles surface.     

The electrochemical reduction of PdCl4 and PdCl6 in polyaniline: Influence of Pd deposit morphology on methanol oxidation in alkaline solution

The controlled uptake and electrochemical reduction of metal precursors PdCl₄²⁻ and PdCl₆²⁻ in polyaniline (PANI) is demonstrated. The formation of PANI/Pd composites is achieved with a reduction in proton doping and an increase in the oxidation of the polymer with Pd deposits physically blocking the nitrogen groups. High surface area filaments (PdCl₄²⁻) or a rough encapsulation (PdCl₆²⁻) of Pd metal on PANI are obtained. The structural differences highlight the influence of the metal precursor oxidation state on the morphology of the Pd deposits in PANI. Thermal gravimetric analysis provides an estimate of the Pd content for each composite of ∼40%. X-ray Photoelectron Spectroscopy and X-ray-excited Auger Electron Spectroscopy analyses confirm the deposition of Pd metal. The catalytic oxidation of methanol was demonstrated for both PANI/Pd composites in alkaline solutions that prohibit proton doping of the polymer. The data indicates that Pd metal acts as a solid-state dopant that may delocalize the charge on the polymer backbone to maintain conductivity. Methanol oxidation at PANI/Pd composites produced using PdCl₄²⁻ was enhanced relative to the composite produced using PdCl₆²⁻ and a planar Pd electrode. Comparison of PANI/Pd composite produced using PdCl₄²⁻ with other Pd catalysts from the literature indicates surface poisoning is reduced when Pd is coupled with the polymer. The composite is robust and stable in alkaline solution with the charge density decreasing by 5% on the positive scan and 13% on the negative scan after 200 voltammetric cycles. The data also indicates that the reductive desorption of surface contaminants is possible, minimizing the catalytic loss due to surface poisoning.     

Preparation of polyaniline-modified TiO2 nanoparticles and their photocatalytic activity under visible light illumination

Titanium dioxide nanoparticles were modified by polyaniline (PANI) using ‘in situ’ chemical oxidative polymerization method in hydrochloric acid solutions. Powder X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier-transform infrared spectra (FT-IR), X-ray photoelectron spectroscopy spectrum (XPS) and UV–vis spectra were carried out to characterize the composites with different PANI contents. The photocatalytic degradation of phenol was chosen as a model reaction to evaluate the photocatalytic activities of the modified catalysts. Results show that TiO₂ nanoparticles are deposited by PANI to mitigate TiO₂ particles agglomeration. The modification does not alter the crystalline structure of the TiO₂ nanoparticles according to the X-ray diffraction patterns. UV–vis spectra reveal that PANI-modified TiO₂ composites show stronger absorption than neat TiO₂ under the whole range of visible light. The resulting PANI-modified TiO₂ composites exhibit significantly higher photocatalytic activity than that of neat TiO₂ on degradation of phenol aqueous solution under visible light irradiation (λ ≥ 400 nm). An optimum of the synergetic effect is found for an initial molar ratio of aniline to TiO₂ equal to 1/100.     

Manganese oxide embedded polypyrrole nanocomposites for electrochemical supercapacitor

MnO₂ embedded PPy nanocomposite (MnO₂/PPy) thin film electrodes were electrochemically synthesized over polished graphite susbtrates. Growing PPy polymer chains provides large surface area template that enables MnO₂ to form as nanoparticles embeded within polymer matrix. Co-deposition of MnO₂ and PPy has a complimentary action in which porous PPy matrix provides high active surface area for the MnO₂ nanoparticles and, on the other hand, MnO₂ nanoparticles nucleated over polymer chains contribute to enhanced conductivity and stability of the nanocomposite material by interlinking the PPy polymer chains. The MnO₂/PPy nanocomposite thin film electrodes show significant improvement in the redox performance as cyclic voltammetric studies have shown. Specific capacitance of the nanocomposite is remarkably high (∼620 F g⁻¹) in comparision to its constituents MnO₂ (∼225 F g⁻¹) and PPy (∼250 F g⁻¹). Photoelectron spectroscopy studies show that hydrated manganese oxide in the nanocomposite exists in the mixed Mn(II) to Mn(IV) oxidation states. Accordingly, chemical structures of MnO₂ and PPy constituents in the nanocomposite are not influenced by the co-deposition process. The MnO₂/PPy nanocomposite electrode material however shows significantly improved high specific capacitity, charge-discharge stability and the redox performance properties suitable for application in the high energy density supercapcitors.     

Manganese ferrite-polyaniline hybrid materials: Electrical and magnetic properties

Magnetic MnFe₂O₄ nanopowders were synthesized by an original solvothermal method in the absence and in the presence of tetra-n-butylammonium bromide (TBAB) and Tween 80 (TW) as surfactants. Manganese ferrite/polyaniline (PANI) hybrid materials were synthesized by in situ polymerization of aniline on the surface of MnFe₂O₄ using ammonium persulfate as oxidant. The purpose of the study was to investigate the influence of the two surfactants on the properties of the MnFe₂O₄ powders and of their composites with PANI. The specific surface area, the cumulative surface area of pores and the cumulative volume of pores are influenced by the nature of surfactant in case of MnFe₂O₄ powders and are higher by comparison to those of the MnFe₂O₄/PANI hybrid materials. The values of saturation magnetization in case of MnFe₂O₄ powders are higher than those of the hybrid materials and are not influenced by the surfactant nature. These features revealed that MnFe₂O₄ powders can be efficiently used as adsorbents for the purification of wastewaters. The values of the electrical conductivity of the composites exhibit a significant increase in comparison to the MnFe₂O₄ powders and depend on the surfactant nature. The highest value of electrical conductivity was achieved by the composite obtained using Tween 80 as surfactant (σ_DC = 54.5·10^?5S?m^?1) which was close to that of PANI (σ_DC = 61.2·10^?5 S?m^?1). The fact that the magnetic and electric properties of the synthesized MnFe₂O₄/PANI composites can be changed by design, demonstrate the high potential of these materials to be used in magneto-electric applications.