Electrochemical performance of carbon paper supercapacitor using sodium molybdate gel polymer electrolyte and nickel molybdate electrode

Journal of Solid State Electrochemistry - Graphene oxide–modified poly (vinyl alcohol)/sodium sulfate-sodium molybdate (GO/PVA-Na2SO4-Na2MoO4, GPSS) gel polymer electrolyte and nickel...     

Diffusive solvent dynamics in a polymer gel electrolyte studied by quasielastic neutron scattering

A quasielastic neutron scattering study has been performed on a polymer gel electrolyte consisting of lithium perchlorate dissolved in ethylene carbonate/propylene carbonate and stabilized with poly(methyl methacrylate). The dynamics of the solvent, which is crucial for the ion conduction in this system, was probed using the hydrogen/deuterium contrast variation method with nondeuterated solvent and a deuterated polymer matrix. Two relaxation processes of the solvent were studied in the 10-400 microeV range at different temperatures. From analysis of the momentum transfer dependence of the processes we conclude that the faster process ( approximately 100 microeV) is related to rotational diffusion of the solvent and the slower process ( approximately 10 microeV) to translational diffusion of the solvent. The translational diffusion is found to be similar to the diffusion in the corresponding liquid electrolyte at short distances, but geometrically constrained by the polymer matrix at distances beyond approximately 5 A. The study indicates that the hindered diffusion of the solvent on a length scale of the polymer network interchain distance ( approximately 5-20 A) is sufficient to explain the reduced macroscopic diffusivity and ion conductivity of the gel electrolyte compared to the liquid electrolyte.     

High-performance supercapacitor coin cell: polyaniline and nitrogen,sulfur-doped activated carbon electrodes in aqueous electrolyte

Journal of Solid State Electrochemistry - We report herein a high energy density asymmetric supercapacitor cell consisting of polyaniline as a positive electrode and heteroatom-doped activated...     

Sorption purification of a halide cobalt electrolyte with organic reagents immobilized on activated carbon

Purification of ammonium-chloride-bromide cobalt-containing electrolyte to remove ions of impurity metals with an adsorbent containing complexing organic reagents immobilized on the surface of synthetic activated carbon was studied.Translated from Zhurnal Prikladnoi Khimii, Vol. 77, No. 12, 2004, pp. 1990–1995.Original Russian Text Copyright © 2004 by Manilevich, Kozin, Bogdanova, Demchenko, Makovetskii.     

Double-layer capacitance of waste coffee ground activated carbons in an organic electrolyte

Using ZnCl₂ activation we prepared a series of carbon electrodes from waste coffee grounds to study the effect of mesopores on double-layer capacitance in a tetraethyl ammonium tetrafluoroborate/acetonitrile electrolyte. The activated carbon with the largest mesopore volume achieved an energy density of 34 Wh kg^?1 at low current loads, and significantly retained an energy density of 16.5 Wh kg^?1 and specific capacitance of more than 100 F g^?1 at fast charge–discharge rates (20 A g^?1). The effect of mesopores on capacitance at fast charge–discharge rates is discussed.     

Prediction of adsorption of organic component and water vapour mixture onto activated carbon

A simple isotherm equation is derived for the adsorption of an organic component onto activated carbon in presence of water vapour. The theoretical results are compared with experimental data for toluene-water vapour-activated carbon, which were published byRipperger andGermerdonk [10].

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Vorhersage der Adsorption einer organischen Komponente und Wasserdampf an Aktivkohle

Zusammenfassung Es wird eine einfache Adsorptionsisotherme abgeleitet, welche die gleichzeitige Adsorption eines organischen Stoffes und Wasser an Aktivkohle beschreibt. Die theoretischen Ergebnisse werden mit experimentellen Resultaten vonRipperger undGermerdonk [10] für Toluol-Wasser-Aktivkohle verglichen.

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Symbols a _i adsorbate concentration in adsorbent, kg/kg of carbon - a _0i monolayer capacity, kg/kg of carbon - b _i kinetic parameter of theLangmuir equation - E _j adsorption energy in thej-th layer - i i-th component (1 — water vapour, 2 — organic compound) - j j-th layer - m number of layers - n number of adsorbed components - p partial pressure, Pa - p* saturation partial pressure, Pa - p _C water vapour partial pressure at begining of capillary condensation, Pa - surface coverage     

有机质子溶剂和有机-水溶液中质子浓度的精确测定

用水标准溶液标定的玻璃电极可用来测定有机质子溶剂和有机-水溶液中质子的水标准活度pHm质子的浓度可用-og[H2S^ ]=pHm-(-logγ-D)来精确测定。(-logγ-D)是一个常数，可以通过对有机质子溶剂和有机-水溶液中强酸-强碱滴定曲线的数学模拟后求得。因此避免了玻璃电极在有机溶剂中标定的困难。     

Effect of partial oxidation and repolarization of TiC-derived nanoporous carbon electrodes on supercapacitor performance using a pH-neutral aqueous electrolyte

Journal of Solid State Electrochemistry - The present study considers TiC-derived carbon (CDC) and its partially oxidized derivative (ox-red-CDC) as potential electrode materials for pH-neutral...     

Preparation of activated carbon from polyaniline by zinc chloride activation as supercapacitor electrodes

Activated carbon for supercapacitor electrode was prepared from polyaniline using chemical activation with ZnCl₂. The morphology, surface chemical composition, and surface area of the as-prepared carbon materials were investigated by scanning electron microscope, atomic force microscopy, X-ray photoelectron spectroscopy, and Brunauer–Emmett–Teller measurement, respectively. Electrochemical characteristics were evaluated by cyclic voltammograms, galvanostatic charge/discharge, and electrochemical impedance spectroscopy tests in 6.0 mol L⁻¹ KOH aqueous solution. The electrochemical measurements showed that ZnCl₂ activation led to better capacitive performances. The activated carbon presented a high-specific gravimetric capacitance of 174 F g⁻¹, with rectangular cyclic voltammetry curves at a scan rate of 2 mV s⁻¹, and it remained 93% even at a high scan rate of 50 mV s⁻¹. These demonstrated that activated carbon would be a promising electrode material for supercapacitors.

     

Preparation of activated carbon from polyaniline by zinc chloride activation as supercapacitor electrodes

Activated carbon for supercapacitor electrode was prepared from polyaniline using chemical activation with ZnCl₂. The morphology, surface chemical composition, and surface area of the as-prepared carbon materials were investigated by scanning electron microscope, atomic force microscopy, X-ray photoelectron spectroscopy, and Brunauer–Emmett–Teller measurement, respectively. Electrochemical characteristics were evaluated by cyclic voltammograms, galvanostatic charge/discharge, and electrochemical impedance spectroscopy tests in 6.0?mol?L^?? KOH aqueous solution. The electrochemical measurements showed that ZnCl₂ activation led to better capacitive performances. The activated carbon presented a high-specific gravimetric capacitance of 174?F?g^??, with rectangular cyclic voltammetry curves at a scan rate of 2?mV?s^??, and it remained 93% even at a high scan rate of 50?mV?s^??. These demonstrated that activated carbon would be a promising electrode material for supercapacitors.     

Photoluminescent phenylated polyfluorenes synthesized in an organic solvent and supercritical carbon dioxide

A number of new phenylated polyfluorenes with blue emission are synthesized via the Diels-Alder reaction in chloronaphthalene and supercritical carbon dioxide. It is shown that these polymers are thermally stable. A comparative analysis of their properties shows that a ??green?? solvent is a suitable alternative to organic solvents for obtaining phenyl-substituted polyfluorenes via the Diels-Alder reaction.     

Separation of the alkali group by thin-layer chromatography using a binary solvent mixture

Summary The use of a binary solvent mixture (nitromethane/benzene) is shown to result in an improved separation of the polyiodides of the entire alkali group on thin-layers of air-most silica gel.

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Zusammenfassung Die Verwendung eines binären Lösungsmittelgemisches (Nitromethan-Benzol) führt zu einer verbesserten Trennung der Polyjodide der ganzen Alkaligruppe auf luftfeuchten Silikagel-Dünnschichten.

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Undergraduate Research Participant, State University of New York at Binghamton, 1966.     

Aerobic oxidative iodination of organic molecules activated by sodium nitrite

Aerobic oxidative iodination activated by sodium nitrite occurs effectively and selectively with 100% iodine atom economy with air as the oxidant. Silica-supported sulfuric acid was used for the activation of the catalyst and iodination. Thus, I₂/NaNO₂/air/silica-supported H₂SO₄ in acetonitrile iodinated aromatics, ketones and aldehydes effectively at ambient temperature.     

Preparation of activated carbon from cotton stalk and its application in supercapacitor

High specific capacitance and low cost are the critical requirements for a practical supercapacitor. In this paper, a new activated carbon with high specific capacitance and low cost was prepared, employing cotton stalk as the raw material, by using the phosphoric acid (H₃PO₄) chemical activation method. The optimized conditions were as follows: the cotton stalk and activating agent with a mass ratio of 1:4 at an activation temperature of 800 °C for 2 h. The samples were characterized by nitrogen adsorption isotherms at 77 K. The specific surface area and pore volume of activated carbon were calculated by Brunauer–Emmett–Teller (BET) and t-plot methods. With these experimental conditions, an activated carbon with a BET surface area of 1,481 cm²?g^?1 and micropore volume of 0.0377 cm³?g^?1 was obtained. The capacitance of the prepared activated carbon was as high as 114 F?g^?1.The results indicate that cotton stalk can produce activated carbon electrode materials with low cost and high performance for electric double-layer capacitor.     

有机质子和有机水溶剂中有机酸pKa值的测定与玻璃电极的标定

在非水质子溶剂和有机．水溶液中有机酸的酸碱平衡常数测定精度与质子浓度的测定精度密切相关。溶液中质子活度可以用水标准溶液标定的玻璃电极用电位法来测定。测得的以水为标准的质子活度pHm,可用-log[H2S^＋]=pHm-（-logγ-D）来转换成质子的浓度,（-logγ-D）是一个与该溶剂有关的常数。用非线性回归法对有机酸的质子交换数与质子溶度关系模拟可以进一步提高有机酸酸度测定的精度。     

High performance pliable supercapacitor fabricated using activated carbon nanospheres intercalated into boron nitride nanoplates by pulsed laser ablation technique

Pliable supercapacitor, yielding specific capacitance (C_s) and energy density as high as 348 F g⁻¹ and 48.3 Wh Kg⁻¹ respectively was fabricated using modified activated carbon electrodes. The nanospheres of activated carbon (AC) were anchored on the nanoplates of boron nitride (BN) by employing the facile technique of pulsed laser ablation in liquid (PLAL) using 532 nm focused laser beam. Four different variants of electrode materials were synthesized by varying the weight percentage (1%, 3%, 5% and 10%) of BN in AC in the PLAL precursor solution. The morphological characteristics, the elemental composition and the structural analysis of the synthesized electrode materials were studied respectively by FESEM, XPS and XRD. The morphological studies indicated that the PLAL synthesis of the electrode materials resulted in proper intercalation of carbon nanospheres into BN nanoplates, which resulted in the observed enhanced performance of the fabricated supercapacitor. Four supercapacitors in this work were fabricated using the four variants of synthesized electrode materials in conjunction with gel polymer electrolyte (GPE). GPE are well known for their non-corrosive nature and best sealing ability to avoid any leakage that results in increasing the cycle life of the device. The performance of the fabricated supercapacitors was evaluated using cyclic voltammetry (CV), galvanostatic charge discharge (GCD) measurement and electrochemical impedance spectroscopy (EIS). The results indicate that the supercapacitor fabricated using 3% BN in AC as electrode material manifested the best specific capacitance and energy density. Also it was found that the supercapacitor maintained 85% of its initial capacitance even after 5000 charge/discharge cycles.     

KOH activated carbon derived from biomass-banana fibers as an efficient negative electrode in high performance asymmetric supercapacitor

Here we demonstrate the fabrication, electrochemical performance and application of an asymmetric supercapacitor(AS) device constructed with β–Ni(OH)_2/MWCNTs as positive electrode and KOH activated honeycomb-like porous carbon(K-PC) derived from banana fibers as negative electrode. Initially,the electrochemical performance of hydrothermally synthesized β–Ni(OH)_2/MWCNTs nanocomposite and K-PC was studied in a three-electrode system using 1 M KOH. These materials exhibited a specific capacitance(Cs) of 1327 F/g and 324 F/g respectively at a scan rate of 10 m V/s. Further, the AS device i.e.,β–Ni(OH)_2/MWCNTs//K-PC in 1 M KOH solution, demonstrated a Cs of 156 F/g at scan rate of 10 m V/s in a broad cell voltage of 0–2.2 V. The device demonstrated a good rate capability by maintaining a Cs of 59 F/g even at high current density(25 A/g). The device also offered high energy density of 63 Wh/kg with maximum power density of 5.2 kW/kg. The AS device exhibited excellent cycle life with 100% capacitance retention at 5000 th cycle at a high current density of 25 A/g. Two AS devices connected in series were employed for powering a pair of LEDs of different colors and also a mini fan.     

活化玻碳电极直接测定全血中的尿酸

用阳极极化法在碱性溶液中活化玻碳电极, 研究了尿酸(UA)在活化玻碳电极(AGCE)上的电化学行为, 并提出一种利用微分脉冲伏安技术测定全血中尿酸的电化学分析方法. 在0.1 mol/L的乙酸缓冲溶液中(pH 5.0), 以0.1 mol/L KCl作为支持电解质, 尿酸在AGCE上于0.484 V 处产生一个灵敏的氧化峰. 微分脉冲伏安法测定其氧化峰电流与 UA 的浓度在5.0×10-6～2.0×10-4 mol/L范围内呈良好的线性关系, 相关系数为0.9989, 检出限为1.0×10-6 mol/L. 该方法操作简便, 重现性较好, 能在抗坏血酸存在下同时测定UA. 用于人血中UA的测定.     

Solid-state graphene-based supercapacitor with high-density energy storage using ionic liquid gel electrolyte: electrochemical properties and performance in storing solar electricity

Journal of Solid State Electrochemistry - The electrochemical properties and high-density energy storage performance of graphene nano-platelet-based solid-state electrical double-layer...