Conductivity electronic transference number

Electronic conductivity of thin-film solid electrolytes. Besides having low electronic transference numbers, it is essential for thin films of the order of 1 jim that the magnitude of the electronic resistance is low in order to prevent self-discharge of the battery. For this reason, specific electronic resistances in the range of 1012-1014 Qcm are required for thin-film solid electrolytes. Often the color may be a valuable indication of the electronic conductivity. In this regard, solid electrolytes should preferably be transparent white [20]. 

According to Peled s model, the existence of an SEI constitutes the foundation on which lithium ion chemistry could operate reversibly. Therefore, an ideal SEI should meet the following requirements (1) electron transference number 4 = 0 (otherwise, electron tunneling would occur and enable continuous electrolyte decomposition), (2) high ion conductivity so that lithium ions can readily migrate to intercalate into or deintercalate from graphene layers, (3) uniform morphology and chemical composition for ho-... 

We begin our discussion by characterizing the electrical conduction in solid electrolytes. These are solids with predominantly ionic transference, at least over a certain range of their component activities. This means that the electronic transference number, defined as... 

Equations (4.94) and (4.95) provide examples of the fundamental equations which describe the electronic conduction in ionic solids. Figure 4-2 shows the electronic transference number tel as a function of the chemical potential of component X. 

The electrical transport properties of alkali metals dissolved in ammonia and primary amines in many ways resemble the properties of simple electrolytes except that the anionic species is apparently the solvated electron. The electrical conductance, the transference number, the temperature coefficient of conductance, and the thermoelectric effect all reflect the presence of the solvated electron species. Whenever possible the detailed nature of the interactions of the solvated electrons with solvent and solute species is interpreted by mass action expressions. 

In the derivation, the hopping conduction of the oxygen vacancies inside the interconnector [33], the conservation of the charge neutrality condition in the mixed conduction of the oxygen vacancies and the holes, and the unity of the electronic transference number are assumed. It has been reported [34] that Dv is experimentally given by... 

The overall permeation rate of a material is determined by both ambipolar conductivity in the bulk and interfacial exchange kinetics. For -> solid electrolytes where the electron - transference numbers are low (see -> electrolytic domain), the ambipolar diffusion and permeability are often limited by electronic transport. 

Provided that the electronic transference number is known, the ionic (and electronic) conductivity may be obtained by differentiation of experimental data. Assume that we have produced a data set for different Po -gradients, keeping the oxygen partial pressure Pq" at the permeate side fixed. Differentiating Eq. (10.10) with respect to the lower integration limit yields. 

A good solid electrolyte should have an ionic conductivity of at least 0.01 (fi cm)" with an electronic transference number that should not exceed 10 . At lOOOK, show that the minimum band gap for such a solid would have to be 4eV. Assume that the electronic and hole mobilities are equal and that each is 100 cm"/V s. State all other assumptions. 

A series of perovskite compositions were synthesized using oxides and carbonates of the cations by conventional ceramic process. The synthesized powders were characterized using powder x-ray diffraction technique to ensure phase purity. Conductivity measurements were made in H2-H2O atmosphere to determine proton conductity. As the perovskite compositions are inherently mixed conducting, the transference numbers for proton and electron conduction were also determined by varying the partial pressures of hydrogen and steam across the membrane. 

B) Electrical property information for the scaling compound, such as electrical conductivity, ionic and electronic transference numbers or the open circuit emf established over the growing scale. 

The correlation between the ionic and electronic conductivity components of orthorhomb-PbO, oxygen pressure and dopant concentration (e.g. K and Bi) has been studied [7]. The electronic component depends on the pressure of oxygen Bi addition creates n-type conductivity, whilst K dopant creates p-type conductivity. The transfer number of Pb is only 0.01 and the ionic conductivity is due entirely to oxygen [6,7]. The exchange of oxygen between the gas and the surface of the oxide proceeds at a slow rate. 

Figure 10.16 Electronic transference number for 1.8 mol% Al-doped BaTiOs, as calculated from thetotal conductivity in Figure 10.6b. The solid lines are calculated from Eq. (66). Data from Ref [13].

The authors also conducted their mechanism study using an RRDE technique and calculated the electron transfer number and the percentage of produced H2O2 according to Eqns (12.4) and (12.5) [2] ... 

Low ionic conductivity and high electronic conductivity. Hence, the electronic transference number should be high along with high electrical conductivily. 

For an ideal SEl for lithium ion batteries, the following requirements must be met (1) electron transference number, fe = 0 (2) high ionic conductivity (3) uniform morphology and chemical composition (4) good adhesion to the anode materials (C, Si, Sn,. ..) surface (5) Good mechanical strength and flexibility (6) low solubility in electrolytes. It should be pointed out that although SEl layers are of paramount importance on anodes, they do exist on cathodes also [51] in lithium ion batteries. Eurther details are available in the previous reviews [1,49,50]. 

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