Papers by Keyword: Electrolyte

Abstract: An electrolyte, N,N′-1-ethyl-4-butyl, triethylene diamine hexafluorophosphate dissolved in glutaronitrile, was developed and investigated in a symmetrical supercapacitor using activated carbon as electrodes (active carbon/active carbon). The electrochemical erformance of the supercapacitor was examined using ac impedance and constant current charging/discharging tests. According to the results, its singleanode specific capacitance could reach 324.7 Fg−1. The supercapacitor also has better capacitance characteristics.

Abstract: Sulfonated poly (ethersulfone) s (S-PDHTPEs) were prepared from 4,4-(2,2-diphenylethenylidene) bisphenol (DHTPE), 4,4-sulfonyldiphenol, 4-fluorophenylsulfone using potassium carbonate, and followed sulfonation reaction with conc. sulfuric acid. DHTPE is a conjugated structure, which enables to form planar conformation between aromatic rings, and selectively sufonated on phenyl rings of polymer side chain. Composite membranes were prepared with copolymers and SiO₂ nanoparticles (20 nm, 4~10%wt). The composite membranes were cast from DMSO. A series of composite membranes structures and characteristic were evaluated by the ¹H-NMR spectroscopy, and thermal stabilities. The membranes were performed by ion exchange capacity (IEC), water uptake and proton conductivity as a function of degree of sulfonation.

Abstract: The perovskite-type Ba(Zr_0.63Ce_0.27)Y_0.1O_3-δ (BZCY) was synthesized by solid-state reaction. Sintering behavior and electrical conductivity of the electrolyte materials were improved through optimizing the content of ZnO as sintering aid. The obvious enhancement of density of sintered body was observed due to ZnO reacting with BZCY powder. Relative densities of the samples increased with ZnO content added. A conductivity of 9.27×10^-3 S/cm tested in humid hydrogen at 800°C was obtained when the ZnO content was 2 mol%. A peak power density of 12.4 mW/cm² was delivered based on a single fuel cell with electrolyte-supported configuration.

Abstract: Two oxides, Y₂O₃ and Nb₂O₅, were doped into Bi₂O₃-based electrolyte in a composition of (Bi _1-x-y,Nb _x,Y _y)₂O ₃, where (x+y)=0.12 to 0.2 and the x:y ratio 3:1 to 1:3. The delta-phase retention, the oxygen vacancy order-disorder transformation, the ionic and electric conductivity were investigated by various techniques. The long-term conductivity of the dense electrolytes was determined showing moderate degradation due to phase transformation possible triggered by surface evaporation of Bi-oxide. The best retention of the conductivity is about 60% after 300 hr test.

Abstract: Microarc oxidation (MAO) coatings were prepared on AZ91D magnesium alloy in a novel dual electrolyte containing various concentrations of sodium citrate (C₆H₅Na₃O₇). The surface and cross-sectional morphologies, coating thickness and surface roughness were characterized by scanning electron microscopy (SEM), layer thickness meter and digital microscope, respectively. The corrosion resistance of coatings was evaluated by electrochemical impedance spectroscopy (EIS). The results showed that both the striking voltage and final voltage decreased gradually with the increase of C₆H₅Na₃O₇ concentration. When the C₆H₅Na₃O₇ concentration increased, surface roughness increased gradually, while thickness of the coating increased at first and then decreased. The coating formed in the electrolyte containing 5g/L C₆H₅Na₃O₇ had a much more uniform and compact microstructure with less micropores and micro-cracks. EIS test showed that the concentration of C₆H₅Na₃O₇ mainly affected the corrosion resistance of inner dense layer, and the coating with best corrosion resistance was obtained in the electrolyte containing 5g/L C₆H₅Na₃O₇.

Abstract: The suitability of some different kinds of liquid electrolytes with a 1M solution of LiCF3SO3 was evaluated for discharging capacity and cycle performance of Li/S cells at room temperature. The liquid electrolyte component was found to have a profound influence on the discharging capacity and cycle property. The lithium–sulfur battery based on the alcohol-ether binary electrolyte shows two discernible voltage plateaus at around 2.4 and 2.1 V, which correspond to the formation of soluble polysulfides and of solid reduction products, respectively. However, the liquid electrolyte based on carbonate electrolyte shows a bad compatibility with sulfur cathode. The lithium sulfur battery can not deliver acceptable discharging capacity and cycle performances.

Abstract: Electrochemical machining （ECM）is a kind of special processing technology which is applied widely, it is particularly suitable for difficult to machine materials, Complex shape or thin-walled parts. The principle of ECM, machining process, the electrode reaction, electrolytic processing speed are analyzed; The electrolytic processing technology and its applications are researched in detail; Research and develop directions of ECM equipment are given; The develop tendency of ECM technology is prospected finally.

Abstract: Electropolishing is a surface finishing process of metals and alloys that enhances brilliant surface finishes with low surface roughness values. The most widely used electrolytes for the electropolishing of stainless steel are varying concentrations of phosphoric and sulphuric acid, and occasionally additives such as chromic acid. The objective of this study was to assess the performance of three commonly used industrial electrolytes in terms of the surface finish of electropolished stainless steel AISI 316L. Each electrolyte had varying sulphuric-phosphoric acid combinations with or without chromic acid. The following electropolishing conditions were assessed: current density, bath temperature, electropolishing time, and initial surface texture. The results revealed that adding chromic acid to the electrolyte did not significantly enhance surface finish, and electropolishing ranges were quite similar for all three electrolytes.

Abstract: A new type of electrolytes for low temperature operation of Li-ion batteries was formulated in this work. Instead of LiPF₆, LiBF₄ and LiODFB were used to form this new type of electrolytes, although LiPF₆ is the mostly chosen solute in the state-of-the-art Li-ion electrolytes. It was found although a LiBF₄-based electrolyte had a lower ionic conductivity than that of a LiODFB-based electrolyte, a LiODFB-based electrolyte demonstrated improved low temperature performance. In particular, at-30°C, a Li-ion cell with 1M LiODFB dissolved in a 1:2:5 (wt.) propylene carbonate (PC)/ethylene carbonate (EC)/ethyl methyl carbonate (EMC) mixed solvent delivered 86% of the capacity obtained at 20°C. Furthermore, the cells with a LiODFB-based electrolyte showed lower polarization at-30°C. The above results suggest that beside the ionic conductivity of an electrolyte as a limitation to the low temperature operation of Li-ion batteries, there was interface impedance having effect on it. Analysis of cell impedance revealed that reduced charge-transfer resistance by using LiODFB resulted in improved low temperature performance of Li-ion batteries.

Abstract: Perovskite oxides comprise large families among the structures of oxide compounds, and several perovskite-related structures are also known. Because of their diversity in chemical composition, properties and high chemical stability, perovskite oxides are widely used for preparing solid oxide fuel cell (SOFC) components. In this work a few examples of perovskite cathode and anode materials and their necessary modifications were shortly reviewed. In particular, nickel-substituted lanthanum ferrite and iron-substituted strontium titanate as cathode materials as well as niobium-doped strontium titanate, as anode material, are described. Electrodes based on the modified perovskite oxides are very promising SOFC components.