Precipitation, solid electrolytes

PP/PE/PP trilayer separators 556 practical batteries 19-61 precipitation, solid electrolytes 540 precursors... 

Figure 5.5. (a) Schematic diagram of cell for recording the dissolution potential of electrolytes A, B, platinum electrodes a, solid phase (electrolyte embedded on the electrode undergoing dissolution) 3, layer of solution in the immediate vicinity of the solid phase 8, solvent phase, (b) Schematic diagram of ceU for the measurement of precipitation potentials A, B, platinum electrodes a, precipitating solid electrolyte ss, super-saturated solution of electrolyte. 

The addition of MgO leads to the formation of a naiTow range of solid solutions at high temperamre, which decompose to precipitate inclusions of tetragonal Zr02 dispersed in cubic zirconia. The material, which functions as a solid electrolyte, has the added advantage that the inclusions stop the propagation of any cracks which may arise from rapid temperature change. 

The reaction mixture is transferred to a 2-L, round-bottomed flask with ethanol washing and the ethanol is removed by rotatory evaporation. Diethyl ether (1 L) is added to precipitate the electrolyte salt, which is collected by filtration and washed with ether. The crude electrolyte is obtained as a white solid (32-32.5 g, theory 34.1 g). The filtrate and washings were combined and evaporated to give a viscous brown oil, which was vacuum distilled through a short Vigreux column (15 x 2.5 cm). After a forerun of 70 mL of material boiling below 150°C (0.15 mm) the product (92-96 g, 53-56%), bp 150-155°C (0.1 mm), is collected (Notes 8 and 9). The forerun contained diethyl maleate, diethyl fumarate, diethyl succinate, and diethyl ethoxy succinate. The product is a mixture of diastereomers on standing some meso isomer, mp 74-75°C, crystallizes. 

The model predicts equilibrium concentrations for metals in concentrated electrolyte solutions which are in contact with a precipitated solid phase. An application of the model to a Great Salt Lake brine showed that predicted cadmium, zinc, and copper solubilities were in good agreement with measured dissolved cadmium, zinc, and copper levels in these same brines. Lead was supersaturated with respect to its basic carbonate in the Great Salt Lake brine according to the model prediction. 

Decreasing operation temperature of solid oxide fuel cells (SOFCs) and electrocatalytic reactors down to 800-1100 K requires developments of novel materials for electrodes and catalytic layers, applied onto the surface of solid electrolyte or mixed conducting membranes, with a high performance at reduced temperatures. Highly-dispersed active oxide powders can be prepared and deposited using various techniques, such as spray pyrolysis, sol-gel method, co-precipitation, electron beam deposition etc. However, most of these methods are relatively expensive or based on the use of complex equipment. This makes it necessary to search for alternative synthesis and porous-layer processing routes, enabling to decrease the costs of electrochemical cells. Recently, one synthesis technique based on the use... 

The solubilities of solid electrolytes in organic solvents are generally lower than they are in water. Thus the solubility of PbS04 or SrS04 can be decreased by the addition of ethanol to water, which thereby facilitates their quantitative precipitation. The solubility decreased effected by the organic solvent probably reflects the influence of the lower dielectric constant which increased the energy required to dissociate the ions. Just... 

While increasing intrinsic conductivity in anion exchange membranes is still focus of research, a major factor influencing effective conductivity is carbon dioxide (CO2). In contrast to alkaline fuel cells (AFCs) with liquid KOH electrolyte, in which carbonate precipitation occurs, in alkaline membrane fuel cells there is no place for salt precipitation, since in solid electrolytes there are no free cation species available for precipitation. However, CO2 still affects the alkaline membrane fuel cell general performance by decreasing the effective conductivity of the anion exchange membranes [15-18], as it is indicated below ... 

On the basis of these results, the Boudouard equilibrium was investigated with Tho.9Lao.1O1.95 as solid electrolyte in the cell CO,C.Fe/FeO.CO,C02, using only the reactive carbon precipitated out of CO iron in metallic or oxide form in the electrodes supported the establishment of the electrode potential catalytically. And with the Zr02 solid electrolyte in a C0,C02.Fe3O4/Pt,O2 cell, the CO2 dissociation equilibrium was investigated [43]. 

Precipitate A solid that forms when two solutions are mixed, 78 Precipitation diagram, 78 Precipitation reaction Formation of an insoluble solid when two electrolyte solutions are mixed, 78,95-96q diagram, 78... 

The great importance of the solubility product concept lies in its bearing upon precipitation from solution, which is, of course, one of the important operations of quantitative analysis. The solubility product is the ultimate value which is attained by the ionic concentration product when equilibrium has been established between the solid phase of a difficultly soluble salt and the solution. If the experimental conditions are such that the ionic concentration product is different from the solubility product, then the system will attempt to adjust itself in such a manner that the ionic and solubility products are equal in value. Thus if, for a given electrolyte, the product of the concentrations of the ions in solution is arbitrarily made to exceed the solubility product, as for example by the addition of a salt with a common ion, the adjustment of the system to equilibrium results in precipitation of the solid salt, provided supersaturation conditions are excluded. If the ionic concentration product is less than the solubility product or can arbitrarily be made so, as (for example) by complex salt formation or by the formation of weak electrolytes, then a further quantity of solute can pass into solution until the solubility product is attained, or, if this is not possible, until all the solute has dissolved. 

Discussion. The turbidity of a dilute barium sulphate suspension is difficult to reproduce it is therefore essential to adhere rigidly to the experimental procedure detailed below. The velocity of the precipitation, as well as the concentration of the reactants, must be controlled by adding (after all the other components are present) pure solid barium chloride of definite grain size. The rate of solution of the barium chloride controls the velocity of the reaction. Sodium chloride and hydrochloric acid are added before the precipitation in order to inhibit the growth of microcrystals of barium sulphate the optimum pH is maintained and minimises the effect of variable amounts of other electrolytes present in the sample upon the size of the suspended barium sulphate particles. A glycerol-ethanol solution helps to stabilise the turbidity. The reaction vessel is shaken gently in order to obtain a uniform particle size each vessel should be shaken at the same rate and the same number of times. The unknown must be treated exactly like the standard solution. The interval between the time of precipitation and measurement must be kept constant. 

Some ionic compounds are soluble, others are not. Consider what happens when we pour a solution of sodium chloride (a strong electrolyte) into a solution of silver nitrate (another strong electrolyte). A solution of sodium chloride contains Na+ cations and Cl anions. Similarly, a solution of silver nitrate, AgNO, contains Ag+ cations and NO, anions. When we mix these two aqueous solutions, a white precipitate, a cloudy, finely divided solid deposit, forms immediately. Analysis shows that the precipitate is silver chloride, AgCl, an insoluble white solid. The... 

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