Electrodes For Electrochemical Supercapacitors Research Articles

Fabrication and Electrochemical Properties of Hydrogenated TiO2 Nanotube Arrays

Nowadays, the requirement for energy and environment are a great challenge for our research society. Energy application and storage become the main issues. As a new energy-storage device with high power density, long cycle life and good application prospect, supercapacitors have attracted growing interest in recent years. The electrode materials for supercapacitors play an important role in the field of electrochemical capacitors. [1-5] In this paper, we report two easy and novel approaches to improve the conductivity of titanium dioxide nanotubes as electrochemical supercapacitor electrodes: first, increase the thickness of the TiO2 nanotube arrays (TNTAs), second, the synthesis of hydrogenated TiO2 NTAs. We fabricated TiO2 for 6 h,12 h and 16 h by anodization respectively(the thicknesses of each TNTAs are 4, 9, 40 micrometer when anodization time increases), and then hydrogenated each of them by electrochemical doping for 5s at the same condition. The H- TiO2 NTAs show great improvement of capacitance. For the 4 um H-TiO2, the hydrogenation improved the capacitance up to 7.83 mFcm-2 from CV calculation at a scan rate of 100mvs-1, which is 11 times higher than the capacitance obtained from TiO2 by air-annealed at the same condition. The largest capacitance we obtained is 25.14 mFcm-2 at a scan rate of 100 mvs-1 for 40 um H-TiO2.Hydrogenation produces reactive oxygen vacancies within the lattice by changing to which increase the host material by acting as a donor. The increase of the thickness provides longer tubular channel path and more active surface sites for ion diffusion and charge transfer. This work provide an suitable route for increasing the electrochemical capacitance of supercapacitors. Reference M. Salari, S.H. Aboutalebi, K. Konstantinov and H.K. Liu, Phys. Chem. Chem. Phys. 13, 5038–41 (2011).J. Wang, J. L. Polleux, J. Lim, B. J. Dunn, Phys. Chem., 111, 14925−14931 (2007).Z.K. Zheng, B.B. Huang, X.Y. Qin, X.Y. Zhang, Y. Dai and M.H. Whangbo, J. Mater. Chem. 21: 9079–87 (2011)X. Chen and S.S. Mao, Chem. Rev. 107, 2891–959(2007)X.H. Lu, G.M. Wang, T. Zhai, M.H. Yu, J.Y. Gan, Y.X. Tong and Y. Li Nano Lett., 12:1690–6 (2012) Figure 1

A Step Potential Electrochemical Spectroscopy Analysis of Capacitance Fade with Increasing Film Thickness in Anodically Electrodeposited Thin Films of Manganese Dioxide

Manganese oxides (MnO2, MnOOH) are promising materials for electrochemical capacitors due to their low cost and toxicity, coupled with their attractive energy storage properties, and as such are well represented in the literature [1]. Thin films of MnO2 prepared by electrodeposition are capable of achieving high values for gravimetric specific capacitance (>2000 F/g) [2], however this rapidly decreases with increasing film thickness. Material activity, as well as material morphology play an important role in determining the capacitive behaviour of a material [3]. Recently, a new method for using step potential electrochemical spectroscopy to separate double layer and faradaic capacitance has been developed [4]. In this presentation, the change in both the double layer and faradaic capacitance with increasing film thickness of anodically prepared deposits will be discussed. With increasing film thickness the gravimetric double layer capacitance increases; however, this is significantly offset by a degradation in material activity, leading to an overall decay in material capacitance. The proposed structural and morphological reasons for these changes will be discussed. 1. Wei, W., et al., Manganese oxide-based materials as electrochemical supercapacitor electrodes. Chemical Society Reviews, 2011(40): p. 1697 - 1721. 2. Cross, A., et al., Enhanced Manganese Dioxide Supercapacitor Electrodes Produced by Electrodeposition. Journal of Power Sources, 2011. 196: p. 7847 - 7853. 3. Conway, B.E., Electrochemical Supercapacitors: Scientific Fundamentals and Technological Applications. 1999, New York: Springer. 4. Dupont, M.F. and S.W. Donne, A Step Potential Electrochemical Spectroscopy Analysis of Electrochemical Capacitor Electrode Performance. Electrochimica Acta, 2015. 167: p. 268 -277.

P-type conductive polymer/zeolitic imidazolate framework-67 (ZIF-67) nanocomposite film: Synthesis, characterization, and electrochemical performance as efficient electrode materials in pseudocapacitors

In the present work, zeolitic imidazolate framework (ZIF-67) was synthesized via chemical routes. For improving the electrochemical performance of the conductive polymer, POAP/ /ZIF-67 composite films were fabricated by POAP electropolymerization in the presence of ZIF-67 as active electrodes for electrochemical supercapacitors. The structural and the valance states of the prepared samples were characterized by X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM). Different electrochemical methods, including galvanostatic charge discharge experiments, cyclic voltammetry, and electrochemical impedance spectroscopy, have been applied to study the system performance. The supercapacitive behavior of the composite film was attributed to the (i) high active surface area of the composite, the (ii) charge transfer along the polymer chain due to the conjugation form of the polymer, and finally, the (iii) synergism effect between the conductive polymer and ZIF-67.

Metal Phosphides and Phosphates-based Electrodes for Electrochemical Supercapacitors.

Phosphorus compounds, such as metal phosphides and phosphates have shown excellent performances and great potential in electrochemical energy storage, which are demonstrated by research works published in recent years. Some of these metal phosphides and phosphates and their hybrids compare favorably with transition metal oxides/hydroxides, which have been studied extensively as a class of electrode materials for supercapacitor applications, where they have limitations in terms of electrical and ion conductivity and device stability. To be specific, metal phosphides have both metalloid characteristics and good electric conductivity. For metal phosphates, the open-framework structures with large channels and cavities endow them with good ion conductivity and charge storage capacity. In this review, we present the recent progress on metal phosphides and phosphates, by focusing on their advantages/disadvantages and potential applications as a new class of electrode materials in supercapacitors. The synthesis methods to prepare these metal phosphides/phosphates are looked into, together with the scientific insights involved, as they strongly affect the electrochemical energy storage performance. Particular attentions are paid to those hybrid-type materials, where strong synergistic effects exist. In the summary, the future perspectives and challenges for the metal phosphides, phosphates and hybrid-types are proposed and discussed.

One-step hydrothermal synthesis of sandwich-type NiCo2S4@reduced graphene oxide composite as active electrode material for supercapacitors

A facile one step hydrothermal process is developed for the synthesis of NiCo2S4@reduced graphene oxide (NiCo2S4@RGO) composite as electrode for electrochemical supercapacitors. This NiCo2S4@RGO electrode exhibits an ultrahigh specific capacitance of 2003Fg−1 at 1Ag−1 and 1726Fg−1 at 20Ag−1 (86.0% capacitance retention from 1Ag−1 to 20Ag−1), excellent cycling stabilities (86.0% retention after 3500 cycles). Moreover, an asymmetric supercapacitor is successfully assembled by using NiCo2S4@RGO nanoparticle as the positive electrode and active carbon(AC) as the negative electrode in 2M KOH electrolyte. The fabricated NiCo2S4@RGO//AC asymmetric supercapacitor exhibits a high energy density of 21.9 Wh kg−1 at a power density of 417.1Wkg−1 and still remains an impressive energy density of 13.5Whkg−1 at a large power density of 2700Wkg−1. The results demonstrate that the NiCo2S4@RGO composite is a promising electrode material as supercapacitors in energy storage.

Influence of newly synthesized geminal dicationic ionic liquid on electrochemical and pseudocapacitance performance of conductive polymer electroactive film

In present work, for improving the electrochemical performance of conductive polymer, POAP/3-methyl-1-[2-(2-{2-[2-[(3-methyl-1-H-imidazol-3-ium-1-yl)ethoxy]ethoxy}-ethoxy)ethyl]-1-H-imidazol-3-ium dichloride (MIEID) composite films have been fabricated by poly ortho aminophenol (POAP) electropolymerization in the presence of MIEID as active electrodes for electrochemical supercapacitors. Different electrochemical methods including galvanostatic charge discharge experiments, cyclic voltammetry and electrochemical impedance spectroscopy have been applied to study the system performance. Analysis of density functional theory (DFT) results show that the atomic-scale electronic properties are generally depend on the bonding and electronic molecular structures (and thus their variation with the external bias in real nano-electrochemical circuits). Composite film kept more than 90% percent of its capacitance after 1000 charging–discharging cycles, while the coulombic efficiency (η) is as high as 95%. Results suggesting composite film can be used as supercapacitor electrode material with excellent specific capacitance (487Fg−1) which indicates this material is a promising electrode material used in high power applications.

Electrochemical synthesis of Sm2O3 nanoparticles: Application in conductive polymer composite films for supercapacitors

A novel electrosynthetic method was introduced to synthesize of Sm2O3 nanoparticles and furthermore, for improving the electrochemical performance of conductive polymer, hybrid POAP/Sm2O3 films have then been fabricated by POAP electropolymerization in the presence of Sm2O3 nanoparticles as active electrodes for electrochemical supercapacitors. The structure, morphology, chemical composition of Sm2O3 nanoparticles was examined. Surface and electrochemical analyses have been used for characterization of Sm2O3 and POAP/Sm2O3 composite films. Different electrochemical methods including galvanostatic charge discharge experiments, cyclic voltammetry and electrochemical impedance spectroscopy have been applied to study the system performance. The supercapacity behavior of the composite film was attributed to the (i) high active surface area of the composite, (ii) charge transfer along the polymer chain due to the conjugation form of the polymer and finally (iii) synergism effect between conductive polymer and Sm2O3 nanoparticles.

Electrosynthesis and pseudocapacitance performance of ionic liquid – Cr (η6-C6H5) complex functionalized reduced graphene oxide/poly ortho aminophenol nanocomposite film

In present work, RGO/IL-Cr composites were synthesized via chemical routes. The structural and valance state of the prepared samples was characterized by X-ray diffraction, X-ray photoelectron spectroscopy. For improving the electrochemical performance of conductive polymer, POAP/RGO/IL-Cr composite films have been fabricated by POAP electropolymerization in the presence of RGO/IL-Cr as active electrodes for electrochemical supercapacitors. Different electrochemical methods including galvanostatic charge discharge experiments, cyclic voltammetry and electrochemical impedance spectroscopy have been applied to study the system performance. The supercapacity behavior of the composite film was attributed to the i) high active surface area of the composite, ii) charge transfer along the polymer chain due to the conjugation form of the polymer and finally iii) synergism effect between conductive polymer and RGO/IL-Cr.

Facile electrodepositing processed of RuO2-graphene nanosheets-CNT composites as a binder-free electrode for electrochemical supercapacitors

A unique nanostructure electrode consisting of RuO2 nanoparticles with ultra-fine diameter (1.9nm) anchored on the surface of graphene nanosheets (GNS) and carbon nanotube (CNT) is prepared as a binder-free supercapacitor electrode through two-step electrochemical routes. At first, free-standing GNS and CNT (GC) are directly deposited on the surface of carbon fiber cloth (CFC) to form a cross-linked composite via a cathodic electrophoretic deposition method. Safranin, a kind of cationic organic dye, is introduced in this stage as a new-type dispersant to disperse GNS and CNT in water to form a suspension solution. After the following electro-deposition process, the as-prepared GC composite is uniform covered with RuO2 nanoparticles. Benefiting from the combined advantages of GNS, CNT and ultra-fine RuO2 nanoparticles in such a binder-free structure, the hybrid electrode exhibits a high specific capacitance up to 480.3Fg−1 (based on the total mass of GNS, CNT and RuO2) and remarkable cycling stability (89.4% capacitance retention after 10000 cycles). Furthermore, the assembled symmetric supercapacitor exhibits a high energy density of 30.9Whkg−1 and power density of 14000Wkg−1 with excellent stability performance (92.7% capacitance retention after 10000 cycles). Thus, the remarkable performance of the resultant RuO2 electrode has provided a rational design strategy for developing supercapacitors with high energy density.

Investigation of graphene oxide nanogel and carbon nanorods as electrode for electrochemical supercapacitor

In this study, a gel of graphene oxide (GO) and carbon nanorods obtained from the GO gel were synthesized via a modified Hummer’s method and a force-driven reflux process respectively. Scanning electron microscopy (SEM) was used to analyse the morphology of the as-synthesized materials showing gelatinous and nanorods structures for the graphene oxide and carbon materials respectively. X-ray diffraction (XRD) suggests that the synthesized materials have a hexagonal crystal structure and an increased interlayer spacing due to the interlaced molecules of oxygen-containing functional groups. X-ray photoelectron spectroscopy (XPS) and energy dispersive X-ray spectroscopy (EDX) analysis were employed to confirm the presence of carbon and oxygen functionalities in the synthesized materials. Electrodes fabricated from both materials prove a limit specific capacitance of 436.5Fg−1 and 719.5Fg−1 corresponding to specific capacities of 48.5mAhg−1 and 80.8mAhg−1 at a current density of 0.5Ag−1 in a three electrode system with 6M KOH electrolyte for both the graphene oxide gel and carbon nanorods respectively. The materials show good cycle stability after 3000 cycling at a current density of 5Ag−1, which implies a great promise as electrodes for supercapacitor applications.

Nanocomposites for Electrochemical Energy Storage - An Overview

Energy storage and conversion are major problems of our modern society. In the last decades, in order to minimize these problems, a growing research activity was dedicated to the development of new systems involved in this energy field. The fabrication of supercapacitors based on new materials, such as electrochemical double layer capacitor, can offer attractive potentialities. Indeed, these supercapacitors are able to provide a power density ten times higher than that supplied by batteries, and allow a larger number of charge and discharge cycles. The performance of supercapacitors highly depends on the properties of electrode materials. Ternary composites combining both capacitive and faradaic reactions can address the improvement necessary for relatively cost effective and performance of supercapacitors. Particularly, ternary nanocomposites systems of carbon nanotubes (CNTs), conducting polymer (CPs) films and metal oxide/hydroxide; CNT:CP:Metal oxide; has been proposed as potential electrodes for electrochemical supercapacitors, as alternatives to overcome the drawbacks associated with single component electrodes for the construction of high performance supercapacitors.

Enhanced pseudocapacitive performance of electroactive p-type conductive polymer in the presence of 1-octadecyl-3-methylimidazolium bromide

In present work, for improving the electrochemical performance of conductive polymer, POAP/1-octadecyl-3-methylimidazolium Bromide ([OMD]Br) composite films have been fabricated by POAP electropolymerization in the presence of [OMD]Br as active electrodes for electrochemical supercapacitors. Different electrochemical methods including galvanostatic charge discharge experiments, cyclic voltammetry and electrochemical impedance spectroscopy have been applied to study the system performance. Analyses of DFT results show that the atomic-scale electronic properties are generally depend on the bonding and electronic molecular structures (and thus their variation with the external bias in real nano-electrochemical circuits). The supercapacity behavior of the composite film was attributed to the (i) high active surface area of the composite, (ii) charge transfer along the polymer chain due to the conjugation form of the polymer and finally (iii) synergism effect between conductive polymer and [OMD]Br.

Direct Growth of Carbon Nanofibers on Nickel Foam and Its Application As Electrochemical Supercapacitor Electrodes

Carbon nanofibers (CNF) are useful for many applications such as polymer reinforcement, electrochemical devices like sensors, batteries, and supercapacitors. The most common method of producing them is by catalytic chemical vapor deposition (CVD) or by electrospinning. CNF growth using CVD is a single step process, unlike electro spinning which requires an additional carbonization step at higher temperatures. In CVD the catalyst is either incorporated directly onto the substrate or introduced with the feed gases. This adds extra cost and set limits to the design of the systems used for the CNF growth process, particularly in cases where porous structures are envisioned. In supercapacitors, the electrode material is most often painted or deposited with an ink of carbon particles. Directly growing the carbon nanomaterial from the supporting surface would eliminate this step and allow complex geometries. It would also help in achieving a higher capacitance by removing the requirement of a binder material and eliminate the occurrence of agglomeration of the active material inherent in the ink deposition process. Another advantage is the higher conductivity of CNF compared to the commonly used active carbon material. With CNF growing directly of the current collector, the addition of conductive carbon black can possibly be eliminated. Finally, an increase access of the electrolyte to the electrode can be expected due to the natural 3-D nano-architecture formed by the CNF. On the other hand, the micro-scale 3-D structure of nickel foams have been the most sought after substrates (current collectors) in the battery and supercapacitor research as they offer more surface area for the deposition of the required active material, together with being non-corrosive in alkali medium. CNF grown directly on Ni-foams are thus expected to extend the performances of supercapacitor electrodes. In this work, we have found a novel method of growing dense CNF on nickel foam. Cyclic voltammetry, galvanotactic charge discharge, and electrochemical impedance spectroscopy was made to electrochemically characterize these CNF/Ni-foam supercapacitor electrodes. When tested as a supercapacitor electrode in 6M KOH, our directly grown CNF gives a good aerial capacitance of about 60 mF/cm2 and an energy density of 16 mWh/m2. We believe this nickel foam with CNF to be very useful in supercapacitors and batteries in decreasing the resistance of the electrochemical device and provide additional surface area.

Influence of ionic liquid on pseudocapacitance performance of electrochemically synthesized conductive polymer: Electrochemical and theoretical investigation

This study demonstrates a method for improving supercapacitive performance of electrochemically synthesized conductive polymer. In this regards, 1-Butyl-3-methyl imidazolium hexafluorophosphate (BI) as a new high efficient ionic liquid was synthesized using chemical approach and then fabricated POAP/BI films by electro-polymerization of POAP in the presence of BI to serve as the active electrode for electrochemical supercapacitor. Theoretical study (AIM) and electrochemical analysis have been used for characterization of ionic liquid and POAP/BI composite film. Different electrochemical methods including galvanostatic charge–discharge experiments, cyclic voltammetry and electrochemical impedance spectroscopy are carried out in order to investigate the performance of the system. This work introduces new most efficient materials for electrochemical redox capacitors with advantages including ease synthesis, high active surface area and stability in an aqueous electrolyte.

Performance evaluation of galvanostatically deposited nickel oxide electrode for electrochemical supercapacitors

Nanostructured nickel oxide (NiO) electrode has been prepared using electrochemical work station operated on galvanostatic mode in supercapacitor application. Crystalline cubic structure and nanoplate-type of morphology of synthesized NiO electrode was confirmed from X-ray diffraction and scanning electron microscopy analysis respectively. The wettability study was tested by contact angle measurement, which reveals hydrophilic nature of NiO electrode with contact angle of 59°. The presence of nickel and oxygen characteristic bands in EDAX and XPS spectrum has corroborated the NiO formation. The supercapacitive properties of NiO electrode were tested by cyclic voltammogram (CV) in 1 M aqueous Na2SO4, KOH, NaOH electrolytes within the potential range of − 1.1 to 0.9 V, 0 to 0.4 V and − 1.2 to 0.4 respectively. The CV study demonstrates maximum specific capacitance of 481.16 Fg− 1 for 1 M Na2SO4. The obtained specific power, specific energy and coulombic efficiency values of NiO electrode are 19.48 kW kg− 1, 60.12 Whkg− 1, and 92.31%, respectively. In the meantime it exhibited excellent cycle life time with 92.3% specific capacitance kept after 1000 cycles. These results imply that NiO electrode is promising candidate for upcoming thin film supercapacitors and other microelectronic constructions.

Fast and reversible redox reaction of MgCo2O4 nanoneedles on porous β-polytype silicon carbide as high performance electrodes for electrochemical supercapacitors

Abstract MgCo 2 O 4 nanoneedles were deposited onto micro and mesoporous silicon carbide flakes (SiCF) to synthesize hybrid electrode materials with high capacitive performance for use as supercapacitors. These SiCF/MgCo 2 O 4 electrodes were fabricated at different MgCo 2 O 4 feeding ratios to determine the optimal MgCo 2 O 4 amount for both total surface area coverage and a suitable redox reaction rate by maximizing the synergy between the electric double layer capacitive effects of SiCF and the Faradic reaction of MgCo 2 O 4 nanoneedles. The SiCF/MgCo 2 O 4 electrode formed at a MgCo 2 O 4 /SiCF feeding ratio of 1.8:1 (SiCF/MgCo 2 O 4 (1.8)) had a specific surface area of 1069 m 2 g −1 . This surface featured the highest specific stored charge capacity of 310.02 C g -1 at a scan rate of 5 mV s -1 with 83.2% rate performance when the scan rate was increased from 5 to 500 mV s -1 in a 1 M KOH electrolyte. The outstanding electrochemical performance of the SiCF/MgCo 2 O 4 (1.8) electrode can be attributed to the ideal electrode material design, considering both the electric double-layer capacitive contribution of SiCF and the battery-type electrochemical behavior of the MgCo 2 O 4 nanoneedles on the SiCF surface. For high capacity electrode materials, this hybrid material strategy introduces possibilities for combinations of porous silicon carbide with other battery-type binary metal oxide materials.

A facile synthetic method and electrochemical performances of nickel oxide/carbon fibers composites

The uniform and completed nanofilms of nickel oxide (NiO) were electrodeposited on the carbon fibers (CFs) by a facile method of cyclic voltammetric. The as-prepared NiO/CFs composites can be used as a flexible electrode for electrochemical supercapacitors. Electrochemical measurements showed that 1.0-NiO/CFs had a good redox process and reversibility, and displayed the specific capacitances as high as 929 F g−1 at a current density of 1 A g−1. After 5000 cycles of charge and discharge, the 1.0-NiO/CFs composite materials could retain more than 88% of initial capacitance and show an excellent cyclability. Meanwhile, this supercapacitor exhibited a higher energy density of 20.8 Wh kg−1 at a power density of 200 W kg−1. The carbon fibers acting as active substrate for the composite electrode are a good conductor and have a larger capacitance of electrical double layer. The nanofilm structure of NiO could facilitate the contact of the electrolyte with the active materials, thus increasing the Faradaic pseudo-capacitance.

Strategies for liquid-liquid extraction of oxide particles for applications in supercapacitor electrodes and thin films

Bottom-up and top-down liquid-liquid extraction methods have been developed for the transfer of colloidal metal oxide particles, synthesized in an aqueous phase, to organic phases. In such methods the agglomeration of the particles during the drying stage was avoided. Hexadecylamine was used as an extractor for MnO2 particles in the bottom-up extraction to the 1-butanol phase and top-down extraction to the dichloromethane phase. The reduction of particle agglomeration facilitated the fabrication of MnO2-carbon nanotube composite electrodes for electrochemical supercapacitors with enhanced mixing of the individual components and active mass as high as 35mgcm−2. Electrochemical testing results showed superior performance of the composite MnO2-carbon nanotube electrodes, prepared by the bottom-up strategy. The new strategies allowed the fabrication of advanced electrodes, which showed a capacitance of 5.48Fcm−2 at a scan rate of 2mVs−1, good capacitance retention at high scan rates and low resistance. In another conceptually new bottom-up strategy colloidal titania particles were modified during synthesis with 2,3,4-trihydroxybenzaldehyde, which allowed strong catecholate-type bonding to the Ti atoms on the particle surface. The Schiff base reaction with hexadecylamine at the liquid-liquid interface allowed for particle extraction. The extraction strategies developed in this investigation pave the way for agglomerate-free processing of advanced films, coatings and devices by colloidal methods.

Review of macroporous materials as electrochemical supercapacitor electrodes

Benefitting from excellent reversibility, high power density, and long cycle lifetime, electrochemical supercapacitors have become a versatile solution to meet the needs of various emerging energy storage applications. Their performances depend strongly on the properties of electrode materials. The composition, morphology, and structure are considered as the most important factors affecting the performances of electrode materials. Many previous review articles have discussed the research advances of some SC electrode materials with similar chemical compositions or microscopic morphologies. However, few review articles put their focus on the specific microstructures. Macropores, as a typical microstructure, can serve as ion-buffering reservoirs to minimize the diffusion distances of electrolyte. Thus, tremendous research efforts have been recently made to design and construct macropores for electrode materials to improve supercapacitive performance. Therefore, in this article, we review the recent developments of macroporous materials for SC applications, primarily including the preparation, microstructure, and performance of macroporous electrode materials. Typical five categories of macroporous electrode materials, including biomass-derived macroporous carbons, non-biomass-derived macroporous carbons, non-carbon-based macroporous materials, macroporous carbon-based composite materials, and active materials supported on macroporous substrates, are discussed in detail. Since mesopores can decrease ion-transport resistance, and micropores favor in-depth interfacial interactions, most porous electrode materials with excellent performance usually contain hierarchical porous structures consisting of macropores, mesopores, and micropores. Thus, the synergistic effects of hierarchical porous structures of various electrode materials are also indicated and summarized in this article. In addition, we also describe the influences of architecture’s several factors on the performance, and the differences in architecture of five categories of electrode materials. Finally, we present our perspectives on the challenges and prospects of macroporous electrode materials.

Sulfonated graphene oxide and its nanocomposites with electroactive conjugated polymer as effective pseudocapacitor electrode materials.

In this work, we synthesized amine functionalized graphene oxide (GOA), by using of 1-methyl, 3-butyl Imidazole ionic liquid, triphenylphosphine, 1,6-diamino hexane in DMSO medium. Afterward, dried GOA used for sulfonated graphene oxide (GOS). For improving electrochemical properties of the poly ortho aminophenol (POAP), we fabricated POAP/GOS films by electro-polymerization of POAP in the presence of GOS to serve as the active electrode for electrochemical supercapacitor. Different electrochemical methods including galvanostatic charge-discharge experiments, cyclic voltammetry and electrochemical impedance spectroscopy are carried out in order to investigate the performance of the system. Finally, the local charge and energy transfer of the molecular system is calculated, using DFT/AIM theories. Results show that the oxygen and nitrogen atoms of phenyl (Ph)/(Ph-OH) rings and -Ph-CO-N-R-N-R″ -SO3H ended functional group, play domain role in intra-molecular charge and energy transfer. The major aim of this computational study method is to propose or effective design electro-chemical molecular systems having different atomic basins/functional groups response (sensitivities) to external voltage. This work introduces new most efficient materials for electrochemical redox capacitors with advantages including ease synthesis, high active surface area and stability in an aqueous electrolyte.