Electrocapacitive Properties Research Articles

Novel ferrocene-based graphene oxide/Polypyrrole nanocomposites: Electro-capacitive properties study

In this research, we fabricated two novel ferrocene-modified graphene oxide (GO) nano-hybrids as electrode material for supercapacitors. Particularly, the physicochemical interaction of GO surface functional groups and as-synthesized ferrocenyl derivative, along with physical addition of polypyrrole (PPy) resulted in the preparation of high-performance battery-type capacitive materials. The GO-FBF1/PPy, and GO-FBF2/PPy, as final nanocomposites exhibited 229.43 and 269.57 mAhg−1 charge storage capacity, and capacity retention of 91 % and 93 % over 5000 CV cycles, respectively. Also, a symmetric supercapacitor (SSC) with GO-FBF2/PPy as both the anode and cathode exhibits exceptional cycling performance, with 95 % of its capacity remaining after 3000 cycles, and can be operated in a broad electrochemical window up to 1.6 V. Furthermore, our SSC device shows remarkable power and energy densities of 7859 W kg−1 and 123 Wh kg−1, respectively. For high-performance SCs, this research offers a way to improve the electrochemical characteristics of redox-active battery-type electrode materials.

Carbon black structural effect within kraft black liquor-based poly(HIPE): enhanced hydrogen storage and electro-capacitive properties

A biopolymer derived from Kraft Black Liquor was successfully incorporated with three types of carbon black, each varying in their characteristics. The resulting carbon materials demonstrate promising performance in energy storage applications.

Mesoporous Ce–Fe–Ni nanocomposites encapsulated in carbon-nanofibers: Synthesis, characterization and catalytic behavior in oxygen evolution reaction

Ceria-iron oxide mesoporous materials with Fe:Ce molar ratio of 5:5 and 9:1 were synthesized by hydrothermal method using CTAB as a template and subsequently modified with NiO (molar ratio Ni:Fe = 1:2) by incipient wetness impregnation technique. In order to increase the electro-capacitive properties and reduce the intrinsic impedance of the metal oxides, the samples were consecutively modified by reduction in hydrogen to obtain highly dispersed Ni–Fe alloys into ceria matrix. By exploiting the high permeability of carbon inside ferrous alloys, the metal phase has been further modified into ferrous carbides and metal alloys encapsulated within carbon nanofibers. For this purpose, a reaction, already widely studied for the production of hydrogen, was used, that is the decomposition of methanol vapors. In fact, this decomposition, in addition to producing syn-gas and methane, changes the catalysts in use through a chemical vapor deposition-carbon coating process. This fact, has been used by us to demonstrate how the newly obtained metal-carbon nanocomposites can be used for electro-catalytic purposes. The modified phases of the two molar ratios of the Fe–Ni–Ce catalysts were tested in the Oxygen Evolution Reaction (OER) in an alkaline environment (1 M KOH), showing a satisfactory and progressive increase in activity and a surprising decrease in the overpotential at 10 mA/cm2 of current density. The morphological, textural and physicochemical properties of the samples were characterized in details by XRD, N2-physisorption, TG-TPO, TEM, EDX, FTIR, XPS, Raman and Moessbauer spectroscopies.

Longan Leaves biomass-derived renewable activated carbon materials for electrochemical energy storage

Biomass-based energy conversion and storage applications have proven to be the most effective technology for practical and sustainable applications. However, their further development was hindered by poor electrode performance. Naturally, abundant biomass is a green alternative carbon source with many desirable properties. This study presents a relatively easy approach for the synthesis of activated carbon-based electrode materials derived from natural biomass with an emphasis on supercapacitor applications. The selected biomass waste is Longan leaves. The precursor was converted into activated carbon through ZnCl2 impregnation at three different concentrations in high-temperature pyrolysis. All activated carbon confirmed a good amorphous structure. Furthermore, oxidative compounds were also found to have an effect on their electrochemical properties. supercapacitor cells prepared in a two-electrode system exhibit high electro-capacitive properties with a specific capacitance of 169.83 F g−1 at a constant current density of 1.0 A g−1 in an aqueous electrolyte of 1 M H2SO4. Furthermore, the optimum energy density was found in LF0.5 samples as high as 19.04 Wh kg−1 at a maximum power density of 124.37 W kg−1.

Synergistic performance of simply fabricated polyaniline/carbon xerogel composite as supercapacitor electrode

Abstract This work involves preparation of loaded polyaniline (PANI)/carbon xerogel (CX) composites with different mass ratios. The effect of PANI loading on the porosity and electrochemical activity of the composites is studied. Surface characterization analysis of studied samples reveals that incorporation of PANI onto the CX network reduces its specific surface area with a simultaneous expansion of the average pore diameter from the microporous to the mesoporous range. The prepared composites are tested as supercapacitor electrodes, and their electro-capacitive properties are studied by cyclic voltammetry, chronopotentiometry and electrochemical impedance spectroscopy in a two-electrode cell using 1 M H2SO4 electrolyte. Results show that introducing PANI into CX network enhances the gravimetric capacitance from 156 to 612 F ∙ g−1 at current density of 0.1 A ∙ g−1 with reasonable stability. For instance, sample composite of PANI:CX = 5:1 w/w displays a retention percentage of 87.6% after 1500 repetitive cycles. In general, this synergy between PANI and CX in the prepared composites is attributed to the development of mesoporosity and the lowering of electrode resistance.

Polyindole modified g-C3N4 nanohybrids via in-situ chemical polymerization for its improved electrochemical performance

In this work, surface modification of graphitic carbon nitride (g-C3N4) nanoflakes is achieved by polyindole (PIn) without using any surfactant via in-situ chemical polymerization. The electro capacitive properties of the materials are directly related to their surface functionalities, microstructure, and interfacial interaction. Therefore, the interface engineering of g–C3N4–PIn nanohybrid is performed to improve the electrochemical activity. The optimal composition of g–C3N4–PIn nanohybrids is investigated by varying amounts of indole monomer (5, 20 and 50 mg) with a fixed weight of g-C3N4 (10 mg) during polymerization. Various spectroscopic/microscopic techniques identify the as-synthesized nanohybrids before exploring their application as metal-free electrode material. In comparison (current density at 2 Ag−1), the 1:2 g–C3N4–PIn nanohybrid exhibits better electrochemical performance over the others. The specific capacitance (Cs) values are estimated as 115.8 Fg−1for 1:2 g–C3N4–PIn and 12.4, 38.7, 21.5, and 66.9 F g-1, for bare g-C3N4, pure PIn, and other two nanohybrids (1:0.5 and 1:5) of g–C3N4–PIn respectively. In this article, the 1:2 g–C3N4–PIn nanohybrid is an optimal weight ratio and advances in strategies on the metal-free and binder-free electrodes with the fast diffusion process of charges. It shows 96% cycling stability over 250 cycles.

Electrochemical behavior of representative electrode materials in artificial seawater for fabricating supercapacitors

Supercapacitors (SCs) based on representative electrochemical electrode materials were assembled and artificial seawater has been proposed as an electrolyte for application in supercapacitor devices for the first time. Seawater is an eco-friendly and unlimited resource and its use as an electrolyte is an entirely new concept for SCs systems. Partially graphitized N-doped porous carbon, MnO2/polypyrrole composite, and Fe2O3 nanosheets were prepared to investigate the electrocapacitive properties of active materials in artificial seawater electrolyte. Furthermore, the aforementioned electrode materials were utilized to fabricate SC devices as the artificial seawater-based supercapacitors. More importantly, long-term cycling tests revealed that carbon-based SC devices showed much higher cycling stability than the other types of SC devices with the former having a high potential for practical application.

Improvement on the Electrocapacitive Properties of NiO with Carbon

Carbon-coated NiO/reduced graphene oxide (NiO/rGO) composites with NiO nanoparticles (∼5 nm) homogeneously distributed and carbon skeletons on the surface were constructed in this work. Graphene ox...

Insight of the effect of graphitic cluster in the performance of carbon aerogels doped with nickel as electrodes for supercapacitors

A series of Ni-doped carbon aerogels with different Ni loadings were prepared and extensively characterized from a textural, chemical and electro-chemical point of view. The formation of graphitic clusters on nickel particles was specially analysed by XPS and Raman spectroscopy. Electro-capacitive properties were studied by cyclic voltammetry, chronopotentiometry, and electrochemical impedance spectroscopy in a three and two-electrode cell, and in acidic media and non-aqueous aprotic electrolyte.The use of Ni as a polymerization catalyst slightly decreases the micropore volume of the carbon aerogels but on the contrary, a great increase in their mesopore volume was obtained. All samples present high gravimetric capacitances, ranging from 182 to 219 F g−1 in 1 M H2SO4, and from 49 to 63 F g−1 in 1 M tetraethylammonium tetrafluoroborate. Results show that the equivalent series resistances decrease as the Ni content increases and the capacitance increases in the same sense. This trend is directly related to the presence of a good developed mesopore network in Ni-doped carbon aerogels and a better electrical conductivity due to the formation of the graphitic clusters around the Ni particles. The stability of the charge-discharge cycles, studied by floating tests, showed a very good performance of the doped-carbon aerogels.

Stannous sulfide nanoparticles for supercapacitor application

A facile hydrothermal method has been employed for the synthesis of stannous sulfide nanoparticles for the electrochemical supercapacitor application. The microscopic, optical and surface property of the synthesized material was characterized using different analytical techniques. The electrochemical performance of the synthesized material was reinforced by introducing carbon black. The electro-capacitive properties of the hybrid material were investigated by cyclic-voltammetry and galvanostatic charge-discharge methods where the system exhibited highest specific capacitance value of 201 F g−1 at the current density of 0.1 A g−1.

Zeolite-templated nanoporous carbon for high-performance supercapacitors

Hierarchical porous carbon prepared with calcium-containing nanocrystalline beta zeolite as the template and ethylene as the carbon source at a relatively low carbonization temperature (600 °C) displayed excellent electrocapacitive properties.

A reduced graphene oxide–NiO composite electrode with a high and stable capacitance

Thermal decomposition of Ni(acac)2 leads to in situ formation of NiO sandwiched between expanded graphite oxide layers, and this material displays good electrocapacitive properties.

Novel layered polyaniline-poly(hydroquinone)/graphene film as supercapacitor electrode with enhanced rate performance and cycling stability

It is a challenge to fabricate polyaniline (PANI) materials with high rate performance and excellent stability. Herein a new special supercapacitor electrode material of polyaniline-poly(hydroquinone)/graphene (PANI-PHQ/RGO) film with layered structure was prepared by chemical oxidative polymerization of aniline and hydroquinone (H2Q) in the presence of RGO hydrogel film. The synergistic effect and loose layered structure of the composite film facilitate fast diffusion and transportation of electrolyte ions through unimpeded channels during rapid charge-discharge process, resulting in high rate capability and stable cycling performance. As a result, the PANI-PHQ/RGO-61 film electrode exhibited 356 F g−1 at a current density of 0.5 A g−1 and high capacitance retention of 83% from 0.5 to 30 A g−1. Moreover, it presented an excellent cycling stability with 94% of capacitance retention in comparison with 60% of pure PANI electrode and an outstanding Coulombic efficiency of 99% after 1000 cycles of galvanostatic charge-discharge. These superior electrocapacitive properties make it one of promising candidates for electrochemical energy storage.

Electrocapacitive properties of nitrogen-containing porous carbon derived from cellulose

A generalised approach to the preparation of nitrogen-containing porous carbon from cellulose for supercapacitor applications is demonstrated in this paper. A sample prepared at a carbonisation temperature of 600 °C with a specific surface area of 781 m2 g−1 and a pore volume of 0.68 cm3 g−1 displayed the best electrocapacitive performance. The well-developed porous structure coupled with the presence of nitrogen-containing functional groups along with nascent hydrogen enabled this sample to exhibit specific capacitances of 248 and 133 F g−1 at current densities of 0.1 and 10 A g−1, respectively, in a symmetric cell with 1 M aqueous H2SO4 solution as the electrolyte. With this electrode, about 89% of the initial capacitance is retained after 2000 cycles at a current density of 1 A g−1. A symmetric supercapacitor fabricated using this carbon in both electrodes exhibits an energy density of 14.6 Wh Kg−1 at a power density of 63.5 W Kg−1 and remains at 7.9 Wh Kg−1 at a power density of 6500 W Kg−1.

Synthesis and electrochemical performance of hydrothermally synthesized Co3O4 nanostructured particles in presence of urea

Abstract Morphology controlled nanostructures of Co3O4 were prepared via hydrothermal synthesis method in presence of varying content of urea as hydrolyzing agent. We demonstrate that change in weight content of hydrolyzing agent, yield profound variations in the oxide microstructure, with plate and brush like structure. This in turn resulted in significant variations in the electrocapacitive properties of these materials. Specifically, Co3O4 nanostructures that were synthesized at low urea content exhibited very favorable electrochemical properties. Amongst the Co3O4 studied, Co3O4-U0.37, prepared with 0.37 g of urea, displayed moderate surface area (50.10 m2/g), highest specific capacitance (764 F/g at 5 mV/s) and energy density (19.56 Wh/kg). The specific capacitance of all Co3O4 decreased with the increase in scan rate. The cyclic stability of Co3O4-U0.37 was studied up to 5000 cycles and about 64% retention of charge storage capacity was observed. The superior electro-capacitive behavior of the Co3O4-U0.37 was attributed to high surface area and brush like structure amongst studied Co3O4. In conclusion, it is demonstrated that the high specific capacitance is achievable in same oxide materials by the tight control of morphology of the oxides. Low hydrolyzing concentration was desired in producing high surface area architecture which provided high specific capacitance.

Synthesis of mesoporous Co(OH)2 nanocubes derived from Prussian blue analogue and their electrocapacitive properties

Taking Prussian blue analogue (Co3[Co(CN)6]2) nanocubes as precursor, mesoporous Co(OH)2 nanocubes were synthesized by simply reacting Co3[Co(CN)6]2 nanocubes with NaOH aqueous solution. Their morphology and microstructures were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy and micropore and chemisorption analyzer. Electrocapacitive properties of mesoporous Co(OH)2 nanocubes were characterized by cyclic voltammetry, electrochemical impedance spectroscopy and galvanostatic charge/discharge method. Results show that the mesoporous Co(OH)2 nanocubes have mainly mesoporous structure with the specific surface area as high as 297m2g−1, a high specific capacitance of 420 Fg−1 at 1 Ag−1 and excellent rate performance (80.9% retention from 1 Ag−1 to 10 Ag−1). In addition, the capacitance of the mesoporous Co(OH)2 nanocubes retained 82.4% of the initial value after 5000cycles even at a high current density of 10 Ag−1. These indicates that the mesoporous Co(OH)2 nanocubes are good candidates for supercapacitor electrode material.

Preparation and Electrocapacitive Properties of Hierarchical Porous Carbons Based on Loofah Sponge.

Four porous carbon samples denoted as LSC-1, LSC-2, LCS-3, and LSC-4 were prepared by carbonization of loofah sponge pretreated by ZnCl2 activation, immersion in N,N-dimethylformamide (DMF), DMF-assisted solvothermal and melamine-assisted hydrothermal processes, and the specific surface areas were 1007, 799, 773, and 538 m2·g−1 with mainly micropores, respectively. Electrocapacitive properties of four porous carbon-based electrodes were investigated with cyclic voltammetry, galvanostatic charge–discharge, and electrochemical impedance spectroscopy in symmetric supercapacitors. All the cyclic voltammetries of four types of supercapacitors showed a rectangular shape, even under a high scan rate of 500 mV·s−1. The capacitances of LSC-1, LSC-2, LSC-3, and LSC-4 were 107.4, 92.5, 60.3, and 82.3 F·g−1 at the current density of 0.1 A·g−1, respectively, and LSC-1 displayed the excellent capacitance retention of about 81.3% with a current density up to 5 A·g−1. All supercapacitors showed excellent electrochemical stability, and the LSC-1-based supercapacitor showed a cycle stability with 92.6% capacitance retention after 5000 cycles at 1 A·g−1. The structure–property relationship of LSC samples is discussed and analyzed on the basis of the experimental data.

Potential‐modulated Electrocapacitive Properties of Soft Microstructured Polypyrrole

AbstractMicrostructured materials are becoming important for high performance electrochemical device especially for energy storage due to their advantageous diffusion and flux properties. Utilizing a rationally designed hollow structured polypyrrole microparticles (PPyMPs) with controllable wall thicknesses of ∼110 to 340 nm, we observed a significant morphological effect on electrocapacitive kinetics of the PPyMPs modulated by the voltammetric potential window and scan rate. The thin‐hollow architecture of PPyMPs revealed significant enhancement of charge storage performance (up to 447 %), high retention at high scan rate and faster charge/discharge kinetics compared to the thick‐hollow PPyMPs due to the larger accessible surface area and decrease of diffusion length. These findings demonstrated the electrocapacitive kinetics performance of microstructured soft materials related to morphological effect modulated by operational conditions. Our study provides new insight on electrochemistry of soft electrode materials with controlled nanostructured morphology for understanding the mechanism of charge insertion and mass diffusion for the future development of high performance porous electrode material.

Control over the morphology and phase of MnOx formed in the modified Hummers' method and impact on the electrocapacitive properties of MnOx–graphite oxide composite electrodes

The controllable morphology and crystalline phase of manganese oxides formed in the Hummer's method have an impact on the electrocapacitive performance of the resulting composite materials.

Effect of dilution ratio and drying method of resorcinol–formaldehyde carbon gels on their electrocapacitive properties in aqueous and non-aqueous electrolytes

Carbon gels were prepared by carbonization of organic gels from a resorcinol–formaldehyde mixture in the presence of potassium carbonate and with two different dilution ratios. The organic hydrogels were dried under supercritical and subcritical conditions and by lyophilization. After carbonization, the carbon aerogels, xerogels, and cryogels were characterized by N2 and CO2 adsorption at −196 and 0 °C, respectively, and by X-ray photoelectron spectroscopy to determine their surface area, porosity, and surface oxygen content. Electrocapacitive properties were studied by cyclic voltammetry, chronopotentiometry, and electrochemical impedance spectroscopy in a two-electrode cell in acidic and non-aqueous aprotic electrolytes. Results obtained showed that the gravimetric capacitance from chronopotentiometry increased linearly for both electrolytes with an increase in the micropore volume accessible to N2 at −196 °C and in the S BET. In both series of carbon gels, the cryogel had the lowest electrical resistance and fastest discharge time from electrochemical impedance spectroscopy, indicating that lyophilization may generate a pore texture with lesser tortuosity and greater regularity in comparison with the other drying methods.