Nickel electrochemical cells

The electrochemical equivalent of iron (if only the first step is taken into account) is 960 Ah/kg and the open-circuit voltage of the nickel/iron cell is 1.4 V. 

For forced-convection studies, the cathodic reaction of copper deposition has been largely supplanted by the cathodic reduction of ferricyanide at a nickel or platinum surface. An alkaline-supported equimolar mixture of ferri- and ferrocyanide is normally used. If the anolyte and the catholyte in the electrochemical cell are not separated by a diaphragm, oxidation of ferrocyanide at the anode compensates for cathodic depletion of ferricyanide.3... 

Wu B. and White R. E., Modeling of a Nickel-Hydrogen Cell. Phase Reactions in Nickel Active Material. J. Electrochem Soc. 2001 148 A595-609. 

Hybinette A process for extracting nickel from sulfide ores. The nickel ore that occurs in Canada is a mixture of the sulfides of nickel, copper, and iron. Several methods have been used to separate these metals. In the Hybinette process, the ore is first smelted in a blast furnace, yielding a nickel-copper matte (i.e., a mixture of their lower sulfides). This is roasted to remove sulfur and leached with dilute sulfuric acid to remove copper. The resulting crude nickel oxide is used as the anode of an electrochemical cell. The nickel deposits on the cathode, which is contained in a cloth bag. Precious metals collect in the anode slime. The process was invented by N. V Hybinette in 1904 and operated at the Kristiansand refinery, Norway, from 1910. 

The reduction is usually made in a multi-compartment electrochemical cell, where the reference electrode is isolated from the reaction solution. The solvent can be water, alcohol or their mixture. As organic solvent A,A-dimethyl form amide or acetonitrile is used. Mercury is often used as a cathode, but graphite or low hydrogen overpotential electrically conducting catalysts (e.g. Raney nickel, platinum and palladium black on carbon rod, and Devarda copper) are also applicable. 

Mechanically robust materials are metals, for example, different chromium-nickel steels, or titanium. Their use in electrochemical cells is limited because they are conductive and may corrode. The corrosion is significantly influenced when the metal is insulated or connected to the anode or to the cathode (see Fig. 9). 

Cross coupling between an aryl halide and an activated alkyl halide, catalysed by the nickel system, is achieved by controlling the rate of addition of the alkyl halide to the reaction mixture. When the aryl halide is present in excess, it reacts preferentially with the Ni(o) intermediate whereas the Ni(l) intermediate reacts more rapidly with an activated alkyl halide. Thus continuous slow addition of the alkyl halide to the electrochemical cell already charged with the aryl halide ensures that the alkyl-aryl coupled compound becomes the major product. Activated alkyl halides include benzyl chloride, a-chloroketones, a-chloroesters and amides, a-chloro-nitriles and vinyl chlorides [202, 203, 204], Asymmetric induction during the coupling step occurs with over 90 % distereomeric excess from reactions with amides such as 62, derived from enantiomerically pure (-)-ephedrine, even when 62 is a mixture of diastereoisomcrs prepared from a racemic a-chloroacid. Metiha-nolysis of the amide product affords the chiral ester 63 and chiral ephedrine is recoverable [205]. 

In [53], oscillatory wave patterns observed during electrochemical dissolution of a nickel wire in acidic media was reported. It was shown that space-averaged potential or current oscillations are associated with the creation of an inhomogeneous current distribution, and that the selection of a specific spatial current pattern depends on the current control mode of the electrochemical cell. In the almost potentiostatic (fixed potential) mode of operation, a train of traveling pulses prevails, whereas antiphase oscillations occur in the galvanostatic (constant average current) mode. 

One-half of an electrochemical cell consists of a pure nickel electrode in a... 

Electroplating is achieved by passing an electric current through a solution containing dissolved metal ions as well as the metal object to be plated. The metal object acts as a cathode in an electrochemical cell, attracting metal ions from the solution. Ferrous and nonferrous metal objects are typically electroplated with aluminum, brass, bronze, cadmium, chromium, copper, iron, lead, nickel, tin, and zinc, as well as precious metals such as gold, platinum, and silver. Common electroplating bath solutions are listed in Table 7-1. 

The manufacture of secondary batteries based on aqueous electrolytes forms a major part of the world electrochemical industry. Of this sector, the lead-acid system (and in particular SLI power sources), as described in the last chapter, is by far the most important component, but secondary alkaline cells form a significant and distinct commercial market. They are more expensive, but are particularly suited for consumer products which have relatively low capacity requirements. They are also used where good low temperature characteristics, robustness and low maintenance are important, such as in aircraft applications. Until recently the secondary alkaline industry has been dominated by the cadmium-nickel oxide ( nickel-cadmium ) cell, but two new systems are making major inroads, and may eventually displace the cadmium-nickel oxide cell - at least in the sealed cell market. These are the so-called nickel-metal hydride cell and the rechargeable zinc-manganese dioxide cell. There are also a group of important but more specialized alkaline cell systems which are in use or are under further development for traction, submarine and other applications. 

Phthalonitrile, CeH CN) has been found to cyclize in an MeOH solution of NiS04 at the cathode of an electrochemical cell to give the nickel phthalocyaninato complex.1115 1116... 

A four-necked electrochemical cell (50 mL) Argon supply and inlet described previously, a magnetic stirring bar, a. Power supply cylindrical rod of zinc as the anode surrounded m pjef ux condenser by a nickel foam cathode... 

B) The nickel-metal hydride (NIMH) rechargeable secondary electrochemical cell, introduced by Beccu87 in 1967, has a nickel oxyhydroxide NiO(OH) electrode and a hydrogen-adsorbing alloy M (e.g., Ti2Ni) at the other electrode in the discharge mode the reaction is... 

An electrochemical cell consists of a nickel metal electrode immersed in a solution with [Ni2+] = 1.0 M separated by a porous disk from an aluminum metal electrode immersed in a solution with [Al3+] = 1.0 M. Sodium hydroxide is added to the aluminum compartment, causing AI(OH)3(s) to precipitate. After precipitation of Al(OH)3 has ceased, the concentration of OH- is 1.0 X 10-4 M and the measured cell potential is 1.82 V. Calculate the Ksp value for Al(OH)3. 

C. P. Milner and U. B. Thomas, The nickel/cadmium cell, in Adyances in Elecirochemislrv and Electrochemical Engineering, Vol. 5, P. Delahay, editor, Wiley-Interscience New York 1967, pp. 1-86. 

An important industrial process for the conversion of organic precursors to fully fluorinated derivatives (perfluo-rocarbon compounds) is the Simons Process. The Simons Process [1-9] uses an electrochemical cell to oxidize per-hydro-organic materials, at a nickel anode, to their perfluoro-relatives. The electrolyte for that process is liquid anhydrous hydrogen fluoride in which sodium fluoride, or other ionizing solutes, are dissolved (the latter, to provide for electrical conductance). 

It is known that nickel can serve as a catalyst for the subsequent CNTs growth. Ni nanoclusters were deposited electrochemically on the exposed silicon at the bottom of etched tracks. For this purpose the nanoporous samples have been inserted into an electrochemical cell with the nanoporous oxide facing solution of 0.5 mol/1 H3BO3 0.5 mol/l NiS04, and the backside being contacted as the cathode with application of-1.2 V DC [5]. 

The electrochemical cell consists of a Teflon block with three interconnected cylindrical wells (See Fig. 2.2). The counter electrode is a polycrystalline nickel disk (12.54 mm diameter) cast in Kel-F and then press fitted into an orifice bored on the Teflon block. The dynamic hydrogen reference electrode, is formed by inserting a platinum wire into... 

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