Nanocomposites For Supercapacitor Applications Research Articles

Gel Combustion Synthesis and Characterization of ZnO/NiO Nanocomposite for Supercapacitor Application

Energy demand is a major concern around the globe of the world. Electrochemical supercapacitors are one among various alternative and green energy devices. The performances of supercapacitors depend mainly on the enhanced properties of electrode materials. In the present work, ZnO/NiO nanocomposite (NCs) was synthesized by a simple and facile citrate-based gel combustion procedure. The crystal structure and phase identification, surface morphology and functional groups of the samples were analyzed by X-ray diffraction (XRD) pattern, scanning electron microscope (SEM) and Fourier-transform infrared spectroscopy (FTIR), respectively. X-ray Diffraction pattern is observed that the crystalline peaks are broader and confirmed nanoparticles. The mean size of the particle is found to be ~25 nm. The prepared sample is analyzed an electrochemical studies such as cyclic Voltammetry, charge discharge and electrochemical impedance spectrum, respectively. The maximum specific capacitance (Scp) is 450 Fg-1 at 0.5 mA/cm2.

Microwave rapid synthesis of NiO/Ni3S2@graphite nanocomposites for supercapacitor applications

Electrode materials with graphite flake layer structure decorated with nickel oxide and nickel sulfide nanoparticles (NiO/Ni3S2) have been prepared by one-pot microwave method. When NiO/Ni3S2@graphite synthesized by microwave is compared with NiO@graphite electrode, the former obtains a high capacitance of 768 F g−1 at 1 A g−1, exceeding 72% (446 F g−1 at 1 A g−1) of the latter. After 1000 cycles of the NiO/Ni3S2@graphite electrode, the specific capacitance remained at 692 F g−1 (at 1 A g−1) with a capacitance retention of 90%. Furthermore, NiO/Ni3S2@graphite and active carbon electrodes could be assembled into asymmetric supercapacitor (ASC), which exhibited a specific capacitance of 68.5 F g−1 at 1 A g−1 in 6 M KOH solution. The NiO/Ni3S2@graphite//AC ASC also showed a relatively high energy density of 28.86 Wh kg−1, maximum power density of 0.77 kW kg−1, and exceptional cycling stability (80% retention after 2000 cycles).

Synthesis, characterization and electrochemical evaluation of a novel high performance GO-Fc/PANI nanocomposite for supercapacitor applications

A novel high-performance nanocomposite based on ferrocene (Fc) functionalized graphene oxide (GO) and polyaniline (PANI) for battery-type supercapacitor applications was successfully synthesized. The GO sheets were functionalized by using 4-ferrocenylbutylamine as a redox compound. Then, the final nanocomposite was obtained by physical treatment of PANI and functionalized GO sheets. The chemical structure, electrochemical behaviors and morphological structure of synthesized compounds were confirmed by Fourier transform infrared spectroscopy (FT-IR), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), galvanostatic charge-discharge measurement (GCD), field emission scanning electron microscopy (FESEM), energy dispersive X-ray (EDX) and X-ray diffraction (XRD) analysis, respectively. The charge storage capacity was calculated from GCD curves. Our calculated results exhibit that the GO-Fc/PANI nanocomposite depicted high mass specific charge retention density of 208 mAh g−1 at current density 2.5 A g−1. These results indicate that the presence of Fc and PANI in the final nanocomposite improved charge transfer property of GO after modification. In addition, the GO-Fc/PANI has shown excellent cycling stability up to 3000 cycles with good retention of 85.54% of the initial charge storage capacity.

A study of charge density distribution and enhanced electrochemical properties of zinc cobaltite/polyaniline nanocomposite for supercapacitor application

Solution combustion method was used to synthesize ZnCo2O4 nanoparticles. Then, physical blending method was used to prepare ZnCo2O4/polyaniline (PANI) composite. The crystallite sizes of the ZnCo2O4 and ZnCo2O4/PANI composites prepared were 17.16 nm and 25.46 nm, respectively, as calculated by XRD studies. The density of nanoparticles, cell parameters, and unit cell volume were calculated by Rietveld refinement technique. The cell volume and lattice constant obtained from the Rietveld method were in good agreement with those of Scherer’s method. Functional groups of the samples were further studied using FTIR. Maximum entropy method (MEM) was employed to study the chemical bonding and electron density distribution of the nanoparticles. The electrochemical properties of the pure and composite materials varied due to the changes in the electron density distribution and chemical bonding. The W–H method and size–strain plot method were used to determine the crystallite size and strain. The results obtained through these methods were in accordance with those of Scherer’s method. The morphological observations made through SEM revealed that the change in morphology of the nanomaterial has enhanced the electrochemical properties of the composite. The shape and size of the pure and nanocomposite observed by SEM and XRD were further confirmed by HR-TEM images. Selected area electron diffraction pattern of HR-TEM images was used to further confirm the crystalline nature of ZnCo2O4 and ZnCo2O4/PANI nanoparticles as examined by XRD. The CV and chronopotentiometry studies were used to study the electrochemical behavior of the samples. The specific capacitance values of pure and composite as obtained from CV study were 711 F/g and 867 F/g, respectively, at the applied current density of 0.5 A/g. Good capacitance retention of 98.9% was achieved for the nanocomposite up to 1000 cycles at a high current density of 4 A/g. The investigation by electrochemical impedance spectrum study also revealed that the nanocomposite exhibited low resistance compared with that of pure. The symmetrical capacitor was assembled by fabricating it with ZnCo2O4/PANI as the electrodes. The high specific capacitance and enhanced efficiency have been achieved due to the presence of PANI in the nanocomposite.

Synthesis, structural and electrochemical characterization of Zn doped iron oxide/grapheneoxide/chitosan nanocomposite for supercapacitor application

Nanocomposite of Zinc doped Iron oxide/Graphene Oxide/Chitosan was prepared using optimized quantity of the components by simple solution mixing-evaporation method. The structure of the composite was studied by UV–Vis, FTIR, XRD, SEM, HRTEM and AFM. The results obtained from these analyses showed the formation of homogeneous mixture with strong interaction between the constituents and evidenced by the shift in peak position in both UV–Vis and FTIR spectra. Band gap calculated was found to be 2.28eV which indicates the conducting nature of the composite. The formation of composite in nano dimensions of around 20 nm was proved by XRD, SEM and HRTEM studies. Thermal stability of the sample was investigated by TG/DTA and DSC techniques and showed improved thermal stability with the increase in glass transition temperature of chitosan by 78°c. Electrochemical characteristics of the composite was studied by cyclic voltammetry and capacitative behavior was studied by impedance studies (EIS). These electrochemical investigations revealed good adherent nature of the composite on electrode surface at pH1 and greater electrochemical stability with well defined redox peaks. EIS showed that the nanocomposite modified electrode exhibited good capacitance behavior with the bode phase angle of 87° which proves it to be a very good candidate for supercapacitor applications.

Graphene oxide‐wrapped polyaniline nanorods for supercapacitor applications

This study depicts the chemical synthesis and supercapacitive behavior of nanocomposites of Polyaniline nanorods wrap with graphene oxide (PANI/GO). Synthesis of PANI/GO nanocomposites was carried out by in situ oxidative solution polymerization of aniline in the presence of Nitric acid, acting as a proton donor. The nanocomposites were characterized by field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy, X‐ray diffraction, Raman spectroscopy, thermal gravimetric analysis, contact angle analysis, cyclic voltammetry, galvanostatic charge–discharge test and electrochemical impedance spectroscopy. FESEM revealed the formation of PANI nanorods with the aspect ratio in the range of 3–5, while TEM revealed the wrapping of GO sheets on the PANI nanorods. Thermal stability showed decreasing trend while surface hydrophobicity was of increasing trend with GO concentration due to partial reduction of GO, as observed in Raman spectra. PANI/10 wt% GO (PANI/GO10) nanocomposite electrode showed highest specific capacitance of 276 F/g as compared with 180 F/g of Pure PANI. Cyclic stability of 80% was retained for PANI/GO10 nanocomposites after 500 cycles at a current density of 0.5A/g as compared with unstable PANI. The enhanced specific capacitance and good cyclic stability with increasing GO concentration revealed the good potential of PANI/GO nanocomposites for supercapacitor applications. POLYM. COMPOS., 40:E1716–E1724, 2019. © 2019 Society of Plastics Engineers

Low-cost synthesis of cubic spinel structured high efficient NiCo2O4/polyaniline nanocomposite for supercapacitor application

In this work, NiCo2O4 nanoparticles were synthesized by solution combustion method and NiCo2O4/PANI composite was prepared by physical blending method. The samples were od. The samples were characterized by Fourier transform infrared spectroscopy, x-ray diffraction analysis (XRD), scanning electron microscope (SEM), high- resolution transmission electron microscope (HRTEM) and Electrochemical studies such as Cyclic voltammetry (CV) and galvanostatic charge—discharge analysis. XRD peaks revealed the crystallite size of the NiCo2O4 and NiCo2O4/PANI composites. The samples were refined using Rietveld refinement method. The values of crystallite size and strain determined by W-H method were in good agreement with the results obtained in the Scherer method. FTIR confirmed the presence of respective functional groups. Morphology was studied by SEM and HRTEM images. The Morphological changes in Composite implied the enhanced electrochemical activity. The crystalline nature of NiCo2O4 and NiCo2O4/PANI nanoparticles observed by XRD study was further confirmed by SAED pattern of HRTEM images. The specific capacitance of the samples were calculated by CV and CP in three electrode configuration. Specific capacitance obtained for NiCo2O4 in 5 mV s−1 was 723 F g−1 and for NiCo2O4/PANI was 882 F g−1 from CV study. The maximum specific capacitance obtained for NiCo2O4 was 729 F g−1 and for the composite NiCo2O4/PANI was 887 F g−1 at the applied current density of 0.5 A g−1 through galvanostatic charge—discharge analysis. NiCo2O4/PANI composites showed potential and high performance, in which the maximum specific capacitance was exhibited.

The effect of electro-polymerization method on supercapacitive properties of poly (o-Anisidine)/CNT nanocomposites

The aim of this work refers to study the effect of electro-polymerization method on supercapacitive properties of a known polymer nanocomposite. Herein, poly (o-Anisidine)/multi-walled carbon nanotube (POA/CNT) nanocomposites for supercapacitor applications are prepared by various electrochemical techniques including potentiodynamic, potentiostatic and galvanostatic. The electrochemical response of the prepared POA/CNT by potentiostatic method, is higher than those which are prepared by other methods. The scanning electron microscopy images show that as the preparation method changes from galvanostatic to potentiostatic, the nanocomposite possesses more pronounced porosity. Also, electrochemical impedance spectroscopy shows that with changing the electro-polymerization method from galvanostatic to potentiostatic, the charge transfer resistance decreases. The obtained specific capacitances by galvanostatic charge-discharge measurements for the nanocomposites which are prepared by potentiodynamic, potentiostatic and galvanostatic methods at 0.6 A g−1 are evaluated at about 177, 323 and 81 F g−1, respectively. Moreover, energy densities for the composite which are prepared by potentiostatic, potentiodynamic and galvanostatic methods at 0.6 A g−1, are calculated at about 16, 8.8 and 4 Wh kg−1, respectively. The results indicate that the electrode material prepared by the potentiostatic method, exhibits a better supercapacitive performance.

Facile synthesis of RuO2 nanoparticles anchored on graphene nanosheets for high performance composite electrode for supercapacitor applications

Ruthenium oxide/graphene (RuO2/G) nanocomposites for supercapacitor applications were prepared by a hydrothermal method using high-quality graphene, which was synthesized by modified hummer's method from the graphite. The results reveal that the RuO2 nanoparticles are evenly dispersed on the graphene sheets. The contact between the RuO2 nanoparticles and graphene can effectively improve the conductivity of RuO2 and prevent the restacking and agglomeration of graphene. In addition, the composites exhibit a good electrochemical-activation behavior, and the graphene in composites significantly influences the electrochemical performance. The RuO2/G composite displays a specific capacitance of 441.1 F g-1 at 0.1 A g−1, and only 6% of the capacitance degrades after 1000 cycles, which demonstrates the composite's excellent cycle stability. Significantly, the RuO2/G composites can achieve a high voltage window of 1.6 V and increase energy density of 61.2 Wh kg−1 at a power density of 183.8 W kg-1 at 1 M of Na2SO4 electrolyte. This attractive performance makes it a promising candidate as an electrode material for supercapacitors.

Liquid Phase Plasma Synthesis of Iron Oxide Nanoparticles on Nitrogen-Doped Activated Carbon Resulting in Nanocomposite for Supercapacitor Applications.

Iron oxide nanoparticles supported on nitrogen-doped activated carbon powder were synthesized using an innovative plasma-in-liquid method, called the liquid phase plasma (LPP) method. Nitrogen-doped carbon (NC) was prepared by a primary LPP reaction using an ammonium chloride reactant solution, and an iron oxide/NC composite (IONCC) was prepared by a secondary LPP reaction using an iron chloride reactant solution. The nitrogen component at 3.77 at. % formed uniformly over the activated carbon (AC) surface after a 1 h LPP reaction. Iron oxide nanoparticles, 40~100 nm in size, were impregnated homogeneously over the NC surface after the LPP reaction, and were identified as Fe3O4 by X-ray photoelectron spectroscopy and X-ray diffraction. NC and IONCCs exhibited pseudo-capacitive characteristics, and their specific capacitance and cycling stability were superior to those of bare AC. The nitrogen content on the NC surface increased the compatibility and charge transfer rate, and the composites containing iron oxide exhibited a lower equivalent series resistance.

Electrochemical performance of Bi2O3 decorated graphene nano composites for supercapacitor applications

Graphene based supercapacitors are being developed as potential devices for large scale energy storage applications with physical flexibility, because of their low cost and high electrochemical performance. This paper is mainly focused on the preparation of pure Bi2O3 and graphene / Bi2O3 based nanocomposite materials via sol–gel method and their physical / electrochemical characterization towards application in supercapacitors. The physical characterization like crystallinity, structure, morphological studies etc. were carried out by XRD, FTIR, SEM, EDAX and HR-TEM techniques. The capacitance behaviour of the prepared electrode materials was examined by cyclic voltammetry, galvanostatic charge–discharge and impedance analysis respectively. Among the two samples studied, Bi2O3/graphene nanocomposite electrode material has exhibited higher specific capacitance of 136.76 Fg−1, which is much higher than the specific capacitance of pure Bi2O3 based electrode (81.03 Fg−1). Moreover, the synthesized nanocomposite electrode material has exhibited good cyclic stability (>95% over 1000 cycles) which may lead to applications in high-performance energy storage devices such as super capacitors.

Synthesis and characterization of NiO/Ni3V2O8 nanocomposite for supercapacitor applications

Size and shape controlled nickel oxide/nickel vanadate (NiO/Ni3V2O8) nanocomposites were achieved by solvothermal method. Ammonium metavanadate and nickel chloride precursor solution in appropriate proportion was dissolved in solvent with sodium hydroxide as reducing and stabilizing agent. Three different products were obtained by varying solvothermal processing time as 10 h, 14 h and 18 h at 160 °C. X-ray diffraction (XRD), Fourier-transform infrared (FTIR), Raman and photo luminescence (PL) studies substantiate NiO/Ni3V2O8 formation. Field emission scanning electron microscope (FESEM) studies provides detailed information about NiO/Ni3V2O8 nanorods configuration. Electrochemical studies were carried out to understand pseudocapacitive properties of obtained products. Estimated specific capacitance for product PVK1 has superior value as 653 Fg−1 at current density 1 Ag−1 due to nanorods regular arrangement with uniform size distribution.

A one-step facile route synthesis of copper oxide/reduced graphene oxide nanocomposite for supercapacitor applications

In this research, a one step, facile route has been undertaken to synthesise copper oxide/reduced graphene oxide (CuO/rGO) nanocomposites. X-ray powder diffraction analysis (XRD) was carried out to identity the crystalline structure and phase of the synthesised sample. Elemental analysis and surface morphological features were analysed using EDX and FESEM Images. Particle size as well as the shape of the as prepared composite was observed from HR-TEM images. Raman spectra illustrated the peak of the individual composite materials. The electrochemical properties of the prepared nanocomposite were investigated. The dielectric behaviour of the sample including dielectric constant, dielectric loss and AC conductivity was measured at various frequency levels. Temperature was varied accordingly to observe the effect of temperature on the dielectric properties of the sample.

Synthesis and Property Studies of Molybdenum Disulfide Modified Reduced Graphene Oxide (MoS2-rGO) Nanocomposites for Supercapacitor Applications

Synthesis and Property Studies of Molybdenum Disulfide Modified Reduced Graphene Oxide (MoS₂-rGO) Nanocomposites for Supercapacitor Applications

Spinel NiCo2O4 and single walled carbon nanotube nanocomposites for high performance supercapacitor application

In the present work, we report the hydrothermal synthesis of NiCo2O4/Single walled carbon nanotubes (SWNTs) nanocomposites for supercapacitor applications. The SWNTs provided the conductive network and favored the growth of NiCo2O4 nanoparticles on its surface to facilitate the collection and transportation of electrons during the electrochemical charge storage performance. Due to the improved conductivity and higher surface area of the NiCo2O4/SWNTs nanocomposites as compared to pure NiCo2O4 nanorods, it exhibited a specific capacitance of 1623 F/g and 1098 F/g at 1mV/s scan rate and 1A/g current density. Obtained energy density and power density of the NiCo2O4/SWNTs nanocomposites were 56.19 Wh/Kg and 9.824 kW/kg respectively. These results demonstrated that the nanocomposites could be a promising candidate for future high performance energy storage devices.

Metal-Organic Framework-Derived Nanoporous Metal Oxides toward Supercapacitor Applications: Progress and Prospects.

Transition metal oxides (TMOs) have attracted significant attention for energy storage applications such as supercapacitors due to their good electrical conductivity, high electrochemical response (by providing Faradaic reactions), low manufacturing costs, and easy processability. Despite exhibiting these attractive characteristics, the practical applications of TMOs for supercapacitors are still relatively limited. This is largely due to their continuous Faradaic reactions, which can lead to major changes or destruction of their structure as well phase changes (in some cases) during cycling, leading to the degradation in their capacitive performance over time. Hence, there is an immediate need to develop new synthesis methods, which will readily provide stable porous architectures, controlled phase, as well as useful control over dimensions (1-D, 2-D, and 3-D) of the metal oxides for improving their performance in supercapacitor applications. Since its discovery in late 1990s, metal-organic frameworks (MOFs) have influenced many fields of material science. In recent years, they have gained significant attention as precursors or templates for the derivation of porous metal oxide nanostructures and nanocomposites for next-generation supercapacitor applications. Even though these materials have widespread applications and have been widely studied in terms of their structural features and synthesis, it is still not clear how these materials will play an important role in the development of the supercapacitor field. In this review, we will summarize the recent developments in the field of MOF-derived porous metal oxide nanostructures and nanocomposites for supercapacitor applications. Furthermore, the current challenges along with the future trends and prospects in the application of these materials for supercapacitors will also be discussed.

Electrochemical synthesis of three-dimensional porous networks of nickel with different micro-nano structures for the fabrication of Ni/MnOx nanocomposites with enhanced supercapacitive performance

We have electrochemically synthesized 3D-porous Ni/MnOx nanocomposites for supercapacitor applications. 3D porous micro-nanostructured networks of nickel were prepared using hydrogen bubbles as a dynamic template at different deposition potentials and times. The prepared nickel films were used then as 3D-porous substrates for anodic deposition of manganese oxide nanostructures. The effects of deposition potential and time on the structure of the prepared nickel scaffolds and especially on the capacitive behavior of the subsequently fabricated 3D-porous Ni/MnOx nanocomposites were investigated. The results show that the areal capacitance and especially the rate capability of prepared Ni/MnOx nanocomposites have improved with increasing the deposition potential or optimizing the deposition time of nickel films in the nanocomposites. The prepared 3D-porous Ni/MnOx nanocomposite, in which the nickel scaffold has been deposited at the potential of −6V and duration of 90s, show almost the highest capacitive performance among all other prepared nanocomposites. This prepared nanocomposite, with the loading mass of 1.65mgcm−2, showed the high areal capacitance of 654mFcm−2 (396.4Fg−1) at the current density of 0.5mAcm−2 (0.3Ag−1) in 0.5M Na2SO4 solution. This nanocomposite also revealed the highest rate capability; the capacitance retention is about 63% (412mFcm−2) with increasing the discharge rate from 0.5 to 20mAcm−2, which is almost twice the observed amount of retention when the deposition potential of Ni films was −2V (31%) or their deposition time was 45s (34%). In addition, the prepared nanocomposite exhibited an outstanding cycling stability. The capacitance retention was about 98.91% after performing 2000 charge-discharge cycles.

Chitin and Chitosan Based Hybrid Nanocomposites for Super Capacitor Applications.

In this paper, we report a facile low-cost synthesis of the chitin and chitosan-based hybrid nanocomposites for supercapacitors. The chitosan and chitin based hybrid composites functional group analysis, structural, optical and morphological properties were characterized using FTIR spectroscopy, Raman spectroscopy, UV-vis spectroscopy and scanning electron microscopy (SEM), respectively. Specific capacitance values of hybrid composites were calculated using cyclic voltammetry, electrochemical impedance spectroscopy and galvanostatic charge–discharge analysis. The hybrid composites asymmetric supercapacitor performance was perceived in the range of −0.2 to 1.0 V. The specific capacitance value was achieved at 542.63 F g−1 at current density value of 0.1 A g−1 for CH-GO-ZnO/PANI hybrid composites. The prepared hybrid nanocomposites exhibit good supercapacitive performance and long-term cycle stability. These results demonstrate the potential of the CH-GO-ZnO/PANI hybrid nanocomposites as a high-performance supercapacitors.

Face-to-face self-assembly graphene/MnO2 nanocomposites for supercapacitor applications using electrochemically exfoliated graphene

Layered graphene/manganese oxide (G/MnO2) nanocomposites for supercapacitor applications were prepared with a face-to-face electrostatic self-assembly method using high-quality graphene, which was obtained from the one-step electrochemical exfoliation of graphite. The results reveal that the graphene and MnO2 nanaosheets need to be oppositely charged for the electrostatic self-assembly process. The face-to-face contact between the MnO2 nanosheets and graphene can effectively improve the conductivity of MnO2 and prevent the restacking and agglomeration of graphene. In addition, the composites exhibit an electrochemical-activation behavior, and the ratio of MnO2/graphene in composites significantly influences the electrochemical performance. The G-2/MnO2 composite displays a specific capacitance of 319Fg−1 at 0.2Ag−1, and only 4.4% of the capacitance degrades after 10,000 cycles, which demonstrates the composite's excellent cycle stability. Furthermore, the composite features a high energy density of 31.5Whkg−1 at a power density of 100Wkg−1. This attractive performance makes it a promising candidate as an electrode material for supercapacitors. Remarkably, although the graphene content in G-4/MnO2 composite is the same, the specific capacitance reduced to 186Fg−1 due to the different mixing times.

Controlled synthesis of MnO2/CNT nanocomposites for supercapacitor applications

In this work, manganese oxide (MnO2)/carbon nanotube (CNT) nanocomposites have been prepared as electrode materials for supercapacitor applications. The materials were synthesised using a traditional and facile chemical deposition method. Effects from CNT amounts, synthesis time, pH value and CNT treatment using nitric acid have been thoroughly investigated. It was found that the sample synthesised for 3 h at pH 5 had achieved the best performance with a specific capacitance of 115 F g−1 at a discharge rate of 0·5 A g−1. A capacitance retention of 95% after 1000 cycles has been observed for the sample synthesised in the neutral environment. We believe that findings from this work will pave a road for nanostructured MnO2/CNT composites with better performance in energy storage applications.