Efficient Electrode Material For Supercapacitors Research Articles

Solvothermal synthesis and electrochemical properties of phase pure pyrite FeS2 for supercapacitor applications

Pyrite FeS2 was synthesized through a simple, cost effective solvothermal method. NaOH was used in the synthesis, which plays a crucial role as a pH regulator. The formation of pyrite FeS2 was confirmed through XRD, Raman Spectroscopy and FTIR. SEM results showed the formation of octahedral shaped particles with slight truncated edges. Thermogravimetric Analysis was performed to determine the properties of the material. The electrochemical studies were performed with a three electrode system to explore its supercapacitive behavior using 1 M Na2SO4 and 3.5 M KOH aqueous electrolytes. The electrochemical tests indicated that pyrite FeS2 exhibits a specific capacitance of 260 F/g at 1 A/g with an energy density of 46.8 Wh/kg. The good capacitance and high energy density makes it suitable to be used as an efficient electrode material for supercapacitors.

Fabrication of hybrid nanocomposite derived from chitosan as efficient electrode materials for supercapacitor

A novel high-performance supercapacitor was fabricated using spinal (nickel ferrite) nanoparticles uniformly implanted into nitrogen-doped carbon matrix. The nanocomposite was fabricated with bimetallic polymer complexes for the first time. The fabricated nanocomposite was characterized using FTIR, TGA, Raman, XRD, BET, XPS, SEM and TEM technique. The nanocomposite used as the electrode material for assembling electrodes for supercapacitor over nickel foam, and show an excellent specific capacitance of 958.33 F g−1 at a current density of 5.0 A g−1 in a two-electrode system, using 6 M KOH solution as electrolyte. The energy density was observed 43.75 Wh kg−1 at a power density of 516.25 W kg−1, moreover, at a high power density of 882 W kg−1, it still attains the energy density of 26.25 W h kg−1 and, supports the well-known Ragone plot. The high cycling stability (9.75% loss over 6000 cycles) has been demonstrated and shows excellent stability. The results manifest the great potential of this nanocomposite for next-generation high-power applications. Thus, an advanced electrode material for high-performance supercapacitor was successfully assembled first time by a simple and scalable synthesis route.

Titania nanotubes dispersed graphitic carbon nitride nanosheets as efficient electrode materials for supercapacitors

Herein, we report the synthesis of a hybrid nanocomposite containing one dimensional (1D) TiO2 nanotube supported over a two dimensional (2D) network of conducting graphitic carbon nitride (g-C3N4) nanosheets by a facile hydrothermal strategy. Symmetric supercapacitors based on the hybrid composite electrodes were fabricated and their electrochemical energy storage performances were evaluated and the results were compared with individual component based supercapacitors. The symmetric supercapacitor based on the composite with 1:4 weight ratios of TiO2 and g-C3N4 exhibited a remarkable increase in the specific capacitance in comparison with the individual components. The improvement in electrochemical behavior of the composite sample was attributed to the increase in surface area of the composite due to the spacer effect of titania nanotubes in the 2D g-C3N4 nanosheets.

One-pot synthesis of covalently functionalized reduced graphene oxide–polyaniline nanocomposite for supercapacitor applications

A high-performance reduced graphene oxide–polyaniline (RGO-PANI) electrode material was prepared through commercially viable, facile one-pot synthesis, applying famed diazotization chemistry and grafting strategy. In this work, 4-nitroaniline was utilized as a grafting substrate to bind reduced graphene oxide and polyaniline covalently to a highly stable and efficient supercapacitor electrode material. The chemical composition and structural analysis of covalently functionalized RGO-PANI nanocomposites were characterized by X-ray diffraction, field-emission scanning electron microscopy, Raman spectroscopy, UV–visible spectroscopy, and Fourier-transform infrared spectroscopy. The electrochemical behavior of the nanocomposites was analyzed through cyclic voltammetry, galvanostatic charge and discharge, and electrochemical impedance spectroscopy. The prepared nanocomposite shows a high specific capacitance of 490 F g−1 in 1 M Na2SO4 with outstanding cyclic stability (10,000 cycles). The applied covalent functionalization through grafting strategy was the principal factor for both high specific capacitance and excellent cyclic stability.

Preparation of three-dimensional vanadium nitride porous nanoribbon/graphene composite as an efficient electrode material for supercapacitors

Three-dimensional vanadium nitride porous nanoribbons/graphene composite with hierarchical porosity was prepared and investigated as the electrode material for supercapacitors. Morphology characterization of vanadium nitride porous nanoribbons/graphene composite indicates that vanadium nitride porous nanoribbons incorporate with graphene nanosheets to from a stable three-dimensional architecture with hierarchical porosity. This unique three-dimensional architecture and the combining effect of vanadium nitride porous nanoribbons and graphene nanosheets network make vanadium nitride porous nanoribbons/graphene composite a high-performance electrode material for supercapacitors. At a current density of 0.3 A g−1, vanadium nitride porous nanoribbons/graphene electrode displays a specific capacitance of 164.4 F g−1, which is much higher than that of pure vanadium nitride electrode. In addition, vanadium nitride porous nanoribbons/graphene composite shows high capacitance retention rate (82% capacitance retention at the current density up to 10 A g−1) and good long-term cycling stability (97.5% capacitance retention over 2500 cycles).

Rapid Production of Mn₃O₄/rGO as an Efficient Electrode Material for Supercapacitor by Flame Plasma.

Benefiting from good ion accessibility and high electrical conductivity, graphene-based material as electrodes show promising electrochemical performance in energy storage systems. In this study, a novel strategy is devised to prepare binder-free Mn3O4-reduced graphene oxide (Mn3O4/rGO) electrodes. Well-dispersed and homogeneous Mn3O4 nanosheets are grown on graphene layers through a facile chemical co-precipitation process and subsequent flame procedure. This obtained Mn3O4/rGO nanostructures exhibit excellent gravimetric specific capacitance of 342.5 F g−1 at current density of 1 A g−1 and remarkable cycling stability of 85.47% capacitance retention under 10,000 extreme charge/discharge cycles at large current density. Furthermore, an asymmetric supercapacitor assembled using Mn3O4/rGO and activated graphene (AG) delivers a high energy density of 27.41 Wh kg−1 and a maximum power density of 8 kW kg−1. The material synthesis strategy presented in this study is facile, rapid and simple, which would give an insight into potential strategies for large-scale applications of metal oxide/graphene and hold tremendous promise for power storage applications.

Synthesis and enhanced electrochemical performance of PANI/Fe3O4 nanocomposite as supercapacitor electrode

Conducting polymer nanocomposites associated with metal oxides are emerging class of pseudocapacitive materials that exhibit enhanced electrochemical performance in energy storage applications. In this work, we fabricated polyaniline (PANI)/Fe3O4 nanocomposite (PFNC) through the in situ polymerization of aniline in presence of microwave synthesised Fe3O4 nanoparticles. The prepared PFNC was characterised by X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The surface morphology was investigated by scanning electron microscopy (SEM), and transmission electron microscopy (TEM) analysis. TEM studies revealed the presence of Fe3O4 nanoparticles wrapped by PANI with size in the range of 40–60 nm. The porous structure is validated by the associated morphology, where the voids are created by the formation of microspheres out of the nanospheres. These spaces boost the electrochemical activity of the PFNC by facilitating more sites for the insertion of electrolytic ions during the electrochemical reaction process. The fabricated PFNC on carbon felt offers the enhanced electrochemical properties and exhibits high specific capacitance (572 F g−1 at 0.5 A g−1), pronounced cycling stability (>5000 cycles at 1 A g−1) with good capacitance retention (82%). An excellent rate performance of 71.9% is also exhibited by the PFNC electrode with ten times the original current density (from 0.5 A g−1 to 5 A g−1). These out-standing characteristics prove that PFNC has a great potential to be exploited as highly efficient electrode materials for supercapacitors.

In-situ growth of MnO2 nanorods forest on carbon textile as efficient electrode material for supercapacitors

Abstract Nowadays, the design and fabrication of high-performance and low-cost electrode materials for energy storage and conversion systems are highly desired. The nanostructured materials are interesting for energy-related applications due to the large surface area, enormous active sites which ensure the complete utilization of active material. In this paper, we report a three-dimensional (3D) MnO2 nanorod forest network on carbon textile (MnO2–NRF@CT) with the hierarchical porous structure as a binder-free electrode material for supercapacitor. MnO2–NRF is directly grown on carbon textile surface by a simple one-step hydrothermal method. The carbon textile greatly improved the graphitization degree in MnO2–NRF composite. Typically, MnO2–NRF@CT sample indicates a partially graphitic structure having a low-intensity ratio of Raman D to G band (ID/IG = 0.68), which significantly increases the electrical conductivity and enhanced the performance of the supercapacitor. Consequently, the MnO2–NRF@CT porous architecture as supercapacitor electrode exhibits outstanding electrochemical performance (961 F g−1 at 1 mA cm−2 in 1 mol/L Na2SO4 electrolyte). The MnO2–NRF@CT shows good capacitance retention by achieving 92% of its initial capacitance after 5000 cycles. The long life and good stability highlighted its great potential for future supercapacitor applications.

Synthesis of copper-cobalt hybrid oxide microflowers as electrode material for supercapacitors

Copper-cobalt hybrid oxide (CuCoO-H) microflowers were prepared by a cost-effective and facile two-step growth-annealing approach toward supercapacitor electrode materials. The unique architecture obtained by adjusting the calcination atmosphere, ultrathin nanosheets with small nanocrystallites providing high specific surface area and appropriate mesoporous structure enhancing electrolyte penetration, as well as synergistic effect among CuCo2O4, Cu2O and CoO makes the CuCoO-H display excellent electrochemical performances, showing the advantages of novel hybrid strategy, which shed new light on searching cheap and efficient electrode materials for supercapacitors. The CuCoO-H electrodes showed outstanding electrochemical stability, after 10,000 cycles of measurements at a current density of 3 A g−1, retaining 99.4% of the initial specific capacitances and impressive high-rate capability (405.36 F g−1 at 20 A g−1). Furthermore, the CuCoO-H as the positive electrode and active carbon as the negative electrode constitute an asymmetric supercapacitor, exhibiting a high energy density of 32.2 W h kg−1 at the power density of 644 W kg−1. At last, two asymmetric supercapacitors were assembled in series to light a red commercial light-emitting diodes (LEDs) for the practical application.

Core-Shell Composite Fibers for High-Performance Flexible Supercapacitor Electrodes.

Core-shell nanofibers containing poly(acrylic acid) (PAA) and manganese oxide nanoparticles as the core and polypyrrole (PPy) as the shell were fabricated through electrospinning the solution of PAA and manganese ions (PAA/Mn2+). The obtained nanofibers were stabilized by Fe3+ through the interaction between Fe3+ ions and carboxylate groups. Subsequent oxidation of Mn2+ by KMnO4 produced uniform manganese dioxide (MnO2) nanoparticles in the fibers. A PPy shell was created on the fibers by immersing the fibers in a pyrrole solution where the Fe3+ ions in the fiber polymerized the pyrrole on the fiber surfaces. In the MnO2@PAA/PPy core-shell composite fibers, MnO2 nanoparticles function as high-capacity materials, while the PPy shell prevents the loss of MnO2 during the charge/discharge process. Such a unique structure makes the composite fibers efficient electrode materials for supercapacitors. The gravimetric specific capacity of the MnO2@PAA/PPy core-shell composite fibers was 564 F/g based on cyclic voltammetry curves at 10 mV/s and 580 F/g based on galvanostatic charge/discharge studies at 5 A/g. The MnO2@PAA/PPy core-shell composite fibers also present stable cycling performance with 100% capacitance retention after 5000 cycles.

Hydrothermal synthesis of reduced graphene oxide-Mn3O4 nanocomposite as an efficient electrode materials for supercapacitors

Mn3O4 nanoparticles (NPs) are decorated with reduced graphene oxide nanosheets (rGO-Mn3O4) through a facile and eco-friendly hydrothermal method. The as-synthesized composite was characterized by XRD, SEM, TEM and Raman spectroscopy. The electrochemical properties of (rGO-Mn3O4) nanocomposite were studied as electrode materials for supercapacitors. The rGO-Mn3O4 nanocomposite exhibit high specific capacitance of 457Fg−1 at 1.0A/g in 1M Na2SO4 aqueous electrolyte. The rGO-Mn3O4 exhibits good capacitance retention by achieving 91.6% of its initial capacitance after 5000 cycles. The excellent electrochemical performance is attributed to the increased electrode conductivity in the presence of graphene network.

Biomass derived nitrogen doped carbon with porous architecture as efficient electrode materials for supercapacitors

Developing porous carbon materials with low-cost, sustainable and eco-friendly natural resources is emerging as an ever important research field in the application of high-performance supercapacitor. In this paper, a simple synthetic method to fabricate nitrogen doped porous carbon (NPC) is developed via a one-pot carbonization of sodium alginate and urea. The as-prepared NPC annealed at 700°C with meso- and macro-porous structure exhibits excellent specific capacitance (180.2F/g at 1A/g) and superior cycling life when serves as electrode materials for supercapacitor. Moreover, the investigation on the annealing temperature demonstrates that NPC pyrolysis at 700°C possesses relatively high pyrrole nitrogen and pyridine nitrogen, which is favorable for enhancing supercapacitor performance. This work extends biomass derived carbon materials in energy storage applications.

Synthesis of 2-D nanostructured BiVO4:Ag hybrid as an efficient electrode material for supercapacitors

2-D BiVO4 nanosheets with monoclinic phase were synthesized at room temperature, and incorporated with Ag to form BiVO4:Ag hybrid materials. The experiments demonstrated that doping Ag has largely increased the electrochemical performances of supercapacitor. Furthermore, the specific capacitance can reach up to 109Fg–1 at 1Ag–1 (the undoped one is of 27Fg–1); energy density has enhanced to 15.2Whkg–1 compared with the pristine one without Ag (3.8Whkg–1). Therefore, doping Ag into bismuth-based compound provides us an alternative approach for the synthesis of 2-D nanostructured hybrid as an efficient electrode material for supercapacitors

3D Vertically Aligned CNT/Graphene Hybrids from Layer‐by‐Layer Transfer for Supercapacitors

The exceptional electrical, optical, thermal and mechanical properties make graphene and carbon nanotubes (CNTs) promising for a large variety of applications, including energy storage. In practice, it is higly important to translator these properties associated with the low‐dimensional carbon nanomaterials into bulk materials/devices. Recent theoretical studies have proven that three‐dimensional (3D) pillared architectures, consisting of parallel graphene layers intercalated by vertically aligned carbon nanotubes (VA‐CNTs) in between, possess desriable transport and mechanical properties in all dimensions while maintaining the excellent properties of their building blocks. However, it remains challenging to experimentally realize such 3D pillared graphene/VA‐CNT hybrids. Here, tunable 3D pillared graphene/VA‐CNT architectures are formed by chemical vapor deposition, and a template‐free contact transfer process is presented, involving the hydrophobic‐hydrophobic interactions between graphene and VA‐CNTs. The resultant 3D graphene/VA‐CNT hybrids are demonstrated to be efficient electrode materials for supercapacitors with good performance. This newly‐developed methodology holds great potential for fabricating various 3D architectures with many other materials for a wide range of multifunctional applications, including energy storage, electrical and thermal managements, and flexible electronics.

Nitrogen-doped graphene/carbon nanohorns composite as a high-performance supercapacitor electrode

Nitrogen-doped graphene/carbon nanohorns composite (NGLC) was prepared by one-step co-pyrolysis of graphene oxide, carbon nanohorns (CNHs), urea, and lignosulfonate. CNHs as spacers were inserted into graphene nanosheets. The introduction of CNHs and the loosened nano-structure of NGLC make it achieve a high specific capacitance of 363Fg−1 at a discharge current density of 1Ag−1, and NGLC exhibits an ultrahigh stability of 93.5% capacitance retention ratio after 5000 cycles. The outstanding comprehensive electrochemical performance of NGLC could meet the need of the future acted as an efficient supercapacitor electrode material.

Sonochemical synthesis of porous nanowall Co3O4/nitrogen-doped reduced graphene oxide as an efficient electrode material for supercapacitors

A composite of nitrogen-doped reduced graphene oxide (NRGO) with nano-sized Co3O4 was prepared using a sonochemical method. The prepared Co3O4/NRGO samples were assessed through field emission scanning electron microscopy, X-ray diffraction, X-ray photoemission spectroscopy, and Raman spectroscopy to obtain chemical, structural and morphological information. The resulting composite (Co3O4/NRGO) was evaluated as a candidate for building supercapacitor electrodes. In this line the electrochemical performance of the tested materials were studied through cyclic voltammetry, galvanostatic charge/discharge, electrochemical impedance spectroscopy, and continues cyclic voltammetry. The electrochemical tests were performed using 3 M KCl solutions as the electrolyte. The evaluations on Co3O4/NRGO-based electrodes revealed the material to have a specific capacitance (SC) of 763 F g−1 at a scan rate of 2 mV s−1, an energy density (ED) of 138 W h kg−1, and a high rate capability. Continues cyclic voltammetry evaluations using Co3O4/NRGO-based electrodes proved the electrodes to be capable of maintaining almost 98.9% of its initial SC after 4000 cycles. Based on the electrochemical evaluations the synthesized nanocomposite was proven to possess the merits of both of its ingredients.

Nitrogen/sulfur co-doping assisted chemical activation for synthesis of hierarchical porous carbon as an efficient electrode material for supercapacitors

The microstructure of carbon materials in terms of its specific surface area and pore structure by its activation, are the key issues which determine the electrochemical performance of supercapacitors. In this work, we developed a particular chemical activation process assisted by nitrogen/sulfur co-doping for the preparation of hierarchical porous carbon materials with high specific surface area, aiming at improving the energy density of supercapacitors. The as-obtained hierarchical porous carbon materials exhibited both high Brunauer-Emmett-Teller surface area of up to 3652m2g−1 for more ions adsorption and high porosity (2.61cm3g−1) for rapid ion transport. Attributed to the synergistic effects of these two features, the porous carbon displays high gravimetric specific capacitance (324Fg−1) in KOH aqueous electrolyte with outstanding rate performance (73.3% capacitance retention at 100Ag−1). The symmetrical supercapacitor based on our hierarchical porous carbon displays a maximum specific energy of 9.76Whkg−1 and 94.5% retention over 10000 cycles at 15Ag−1. This synthesis strategy is facile, low-cost and industrialized, which provide a promising route to prepare the hierarchical porous carbon materials for energy storage and renewable delivery devices.

Single atom (K/Na) doped graphitic carbon Nitride@MnO2 as an efficient electrode Material for supercapacitor

Vertically assembled two-dimentional materials have great scientific and technological promise. In this work, altrathin atom doped graphitic carbon nitride (g-C3N4) was synthesised via thermal treatment of thiourea and KBr/NaBr. Free-standing manganese dioxide nanoflakes were uniformly grown on K/Na doped g-C3N4 through hydrothermal reaction. The K doped g-C3N4@ MnO2 has a specific capacitance twice higher than that of pure g-C3N4@ MnO2. This unique design brought excellent specific capacitance (375Fg−1) and cycle stability, which showed that atom doping is an effective approach to enhance electrochemical performance. In addition, the low cost, facial synthesis and small amount of addings make this strategy an optimized approach to construct g-C3N4 based electrode materials.

Synthesis of Self Nitrogen/Phosphorus Doped Carbon Derived from Pea Protein As an Efficient Electrode Material for Supercapacitors

Supercapacitors are energy storage devices that have many applications from memory storage devices, vehicle power supplies, micro sensors and so on. Recently, the electrode material of supercapacitors have been manufactured from fossil fuels which have many concern for depletion therefore, there is urgent to find low cost, eco-friendly and advance carbon electrode materials. In this context, the development of nitrogen-doped porous activated carbons from biomass is of significance for electrode materials. Herein, we report a simple route to prepare phosphorons/nitrogen-doped porous carbon derived from pea protein via hydrothermal carbonization (HTC) and the post-annealing treatment. The surface, textural and morphological properties of synthesized materials were investigated by SEM, XPS, Raman, FTIR and surface area analyzer. A series of mesoporous carbon up to 7.6 N and 2.2 wt. % P along with high the BET surface were synthesized successfully. The obtained materials depicts graphitic carbon particles. Electrochemical properties of the prepared materials were analyzed by cyclic voltammetry (CV), charge-discharge (CD), electrochemical impedance spectroscopy (EIS), KOH and H2SO4 electrolyte solution. The PGC-700 shows outstanding capacitive performance (299 F g-1 at 1 A g-1) , good rate capacitive , and excellent cycling stability due to the synergistic effect of N, P-doped species. This work opens up a new way to prepare advance N/P-doped carbon materials with tailored properties.

A novel high-performance supercapacitor based on high-quality CeO2/nitrogen-doped reduced graphene oxide nanocomposite

In this work, we have developed a novel nanocomposite via deposition of ceria (CeO2) on nitrogen-doped reduced graphene (CeO2/NRGO). NRGO was synthesized through a facile, safe, and scalable method to achieve simultaneous thermal reduction along with nitrogen doping of graphene oxide (GO) in air at much lower reaction temperature. CeO2/NRGO was prepared via a sonochemical method in which ceria nanoparticles were uniformly distributed on NRGO sheets. The structure and morphology of CeO2/NRGO nanocomposites were characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FT-IR), and Raman spectroscopy. Electrochemical properties of the proposed nanocomposite electrodes were investigated by cyclic voltammetry (CV), galvanostatic charge/discharge, continuous cyclic voltammetry (CCV), and electrochemical impedance spectroscopy (EIS) measurements. CeO2–NRGO nanocomposite electrodes showed excellent supercapacitive behavior, including much higher specific capacitance (230 F g−1 at 2 mV s−1) and higher rate capability compared to pure N-graphene. The cycling stability of the electrodes was measured by continues cyclic voltammetry (CCV) technique. The CCV showed that the specific capacitance of the CeO2/NRGO and NRGO nanocomposite maintained at 94.1 and 93.2% after 4000 cycles. The results suggest its promising potential as efficient electrode material for supercapacitors.