Electrolytes In Galvanic Cells Research Articles

Кристаллофизическая модель ионного переноса в монокристаллах супериоников Ba-=SUB=-1-x-=/SUB=-La-=SUB=-x-=/SUB=-F-=SUB=-2+x-=/SUB=- и Ca-=SUB=-1-x-=/SUB=-Y-=SUB=-x-=/SUB=-F-=SUB=-2+x-=/SUB=-

Based on the electrophysical and structural data, a crystallophysical model of ion transfer in superionic conductors Ba1-xLaxF2 + x and Ca1-xYxF2 + x (space group Fm3m) is proposed, in which the charge carriers are mobile interstitial ions Fmob-, formed as a result of heterovalent substitutions of fluorite fragments [M14F64] (M = Ca, Ba) into structural clusters [M8R6F69] (R = La, Y). Single crystals of solid solutions Ca1-xYxF2 + x (0.02≤ x≤0.16) and Ba1-xLaxF2 + x (x = 0.31) were obtained by directional crystallization of the melt. The mobilities of ionic carriers in isostructural superionics Ba0.69La0.31F2.31, Ca0.84Y0.16F2.16, Pb0.67Cd0.33F2, and Pb0.9Sc0.1F2.1 are compared. Crystals Ba1-xLaxF2 + x and Ca1-xYxF2 + x with improved conductometric and mechanical characteristics are promising for replacing the traditional CaF2 electrolyte in galvanic cells for thermodynamic research of chemicals.

Solvent-Dependent Thermoelectric Performance of PC-=SUB=-70-=/SUB=-BM

Based on the electrophysical and structural data, a crystallophysical model of the ionic transport in superionic conductors Ba1-xLaxF2+x and Ca1-xYxF2+x (space group Fm¯3m), in which the charge carriers are mobile interstitial ions F− resulting from heterovalent substitutions of fluorite fragments of [M14F64] (M = Ca, Ba) by structural clusters of [M8R6F69] (R = La, Y). Single crystals of Ca1-xYxF2+x (0.02<x<0.16) and Ba1-xLaxF2+x (x = 0.31) solid solutions were obtained by directed crystallization of the melt. The mobility of ionic carriers in isostructural superionics Ba0.69La0.31F2.31, Ca0.84Y0.16F2.16, Pb0.67Cd0.33F2, and Pb0.9Sc0.1F2.1 are compared. Crystals of Ba1-xLaxF2+x and Ca1−xYxF2+x with improved conductometric and mechanical characteristics are promising active to replace the traditional CaF2 electrolyte in galvanic cells for thermodynamic research of chemicals.

Evaluation and Performance of Cobalt-Doped YSZ Electrolyte

Cobalt doped yttria-stabilized zirconia (YSZ) was evaluated in terms of sintering behavior, electrical conductivity and microstructure as well as performance in solid oxide fuel cells. Cobalt addition increased the total electrical conductivity of YSZ, unlike Mn addition which reduced the conductivity. YSZ doped with 1 at% Co has negligible electronic conductivity and is applicable as the electrolyte in galvanic cells. It is shown that cobalt doping reduces the sintering temperature of YSZ. Consequently, cell performance can be enhanced significantly due to the elimination of interface reaction by sintering at a lower temperature.

Electrical properties of A′Ca2Nb3O10 (A′=K, Rb, Cs) layered perovskite ceramics

The electrical conductivity properties of Dion-Jacobson type layered perovskites A′Ca2Nb3O10 (A′=K, Rb, Cs) was investigated under different gas atmospheres. An increase in the electrical conductivity by about 2–5 orders in magnitude in both ammonia and hydrogen atmospheres is observed compared to air. Among the members of the series, the compound with the smallest size of the alkali ion, i.e. KCa2Nb3O10, exhibits the highest conductivity. In air and hydrogen, a single activation energy value in the range 0.25 – 0.80 eV is observed, while in ammonia a sharp increase in the electrical conductivity is found at about 500 °C. The activation energy at low-temperatures (300–500 °C) is attributed to ionic motion and at higher temperatures (500–700 °C) to both defect formation and ionic motion. The unusual electrical conductivity behavior in ammonia is explained on the basis of the model developed for alkali halides. EMF measurements reveal that the layered perovskites are ionic (proton) conductors. The electrical conductivity changes as a function of the ammonia gas concentration; accordingly, layered perovskites appear to be useful solid electrolytes in galvanic cells for practical applications, e.g. for gas sensors.

Preparation and characterization of polycrystalline lead-exchanged sodium betaII-Alumina and its use as a Pb2+ ion-conducting electrolyte for galvanic cells

Sodium in Na+β″-alumina was partially exchanged with lead by ion exchange between polycrystalline Na+β″-alumina and a molten salt mixture containing lead cations. Examination of the exchanged material showed that it was free of cracks and porosity and that the lead was uniformly distributed. The bulk conductivity of the exchanged material was measured using molten lead electrodes and a two-probe alternating current technique. The electrochemical behavior of lead ions in the material was investigated using a concentration cell of the type W, Pb (1) |Pb-partially-exchanged Na+β″-alumina|Pb−Bi (1), W It was found that the lead ion behaved as Pb2+, and its mobility was high in the exchanged Na+β″-alumina over the range 723 to 1098 K. It is concluded that the prepared Pb2+−Na+βt″-alumina could-be used as Pb2+ ion-conducting solid electrolytes in galvanic cells for thermodynamic measurements on Pb-containing and Na-free metallic melts or Pb2+-containing and Na+-free slags or mattes.

Calciumβ″-alumina and Nasicon electrolytes in galvanic cells with solid reference electrodes for detection of sulphur oxides in gases

Calcium-β″-alumina and Nasicon were applied as solid electrolytes for SOx (x=2 or 3) gas detection. The following two galvanic cells with solid reference electrodes were assembled $$\begin{gathered} Pt|O_2 ,CaO||Ca - \beta '' - Al_2 O_3 ||CaSO_4 |SO_3 ,SO_2 ,O_2 |Pt \hfill \\ Pt|O_2 ,Na_2 O||Nasicon||Na_2 SO_4 |SO_3 ,SO_2 ,O_2 |Pt \hfill \\ \end{gathered} $$

Measurement of iodine vapour pressures in the range 10 4-10 0 Pa by use of γ-AgI as the solid electrolyte in galvanic cells

A galvanic cell is presented to measure equilibrium iodine partial pressures in the Te-I system. The cell arrangement allows the determination of rather low vapour pressures. The cell performance at higher iodine pressures was verified by measuring the e.m.f. of the formation reaction of AgI from the elements in the temperature range from 300 to 420 K, which is above the melting point of iodine. γ-AgI rather than β-AgI was the solid electrolyte used in these investigations. An attempt was made to estimate the lower limit of measurable iodine activities.

Fluoride‐Conducting Solid Electrolytes in Galvanic Cells

Concentrated fluoride‐excess solid solutions based on the alkaline earth fluorides and with and as dopants are suitable solid electrolytes for application in thin film galvanic cells. Galvanic cells were fabricated using Pb or Ca as the anode, the concentrated solid solutions as electrolytes, and either or as the cathode. Discharge characteristics were studied in air from 300° to 540°K. The cells are rechargeable. The electrical properties of were studied and compared with data reported for . Partly discharged cells contain anode passivation layers which consist mainly of when Pb is the anode, and of nominally pure in which fluoride interstitials carry the current if Ca is the anode

ChemInform Abstract: ELECTROMOTIVE FORCE MEASUREMENTS ON CELLS INVOLVING BETA‐ALUMINA SOLID ELECTROLYTE

Open circuit emf measurements have been made to demonstrate that a two-phase, polycrystalline mixture of beta- alumina and alpha-alumina could be used as a solid electrolyte in galvanic cells with reversible electrodes fixing oxygen or aluminum chemical potentials. These measurements indicate that such a two phase solid electrolyte can be used to monitor oxygen chemical potentials as low as that corresponding to Al, Al2O3 coexistence. The activity of Na2O in beta-alumina in coexistence with alpha-alumina was also determined by emf measurements.

Electromotive Force Measurements on Cells Involving Beta‐Alumina Solid Electrolyte

Open‐circuit emf measurements have been made to demonstrate that a two‐phase, polycrystalline mixture of β‐alumina and α‐alumina could be used as a solid electrolyte in galvanic cells with reversible electrodes fixing oxygen or aluminum chemical potentials. These masurements indicate that such a two‐phase solid electrolyte may be used to monitor oxygen chemical potentials as low as that corresponding to Al, coeistence . The activity of in β‐alumina in coexistence with α‐alumina was also determined by emf measurements.

Cuprous Halide and Cuprous Sulfide as Electrolytes in Galvanic Cells

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Glasses as Electrolytes in Galvanic Cells: Silver Glasses

The behavior of glass as an electrolyte in galvanic cells has been used as a means to study the constitution of glass. Potentials have been measured in cells made of alkali borate, silicate, and phosphate glasses containing heavy‐metal ions. The magnitude of the potentials is indicative of the forces between these heavy‐metal ions and the glass. Platinum electrodes were used. For Ag+ glasses, cells of the type Pt/Ag+ glass/Ag/‐ Pt were formed by reduction of the Ag+ ions in the vicinity of one electrode by hydrogen between 200° and 400°C. The e.m.f. of these cells were of the order of 1.0 volt for silicate glasses, 0.7 volt for borate glasses, and 0.3 volt for phosphate glasses. The interpretation of these potentials is based on the stability of the Ag+ ions in the different glasses.