Electrolytes ionic compounds defect concentration

The probability of formation of the local heat source greatly increases if the distribution of pore sizes in the material of the separator is highly nonuniform and the local defect of the film at lithium falls in an anomalously narrow pore (small S). This probability also highly increases in the case of nonuniform electrolyte and the defect falls in a pore, where the concentration of the ionic compound is decreased (small k). Thus, the appearance of local heat sources, capable of initiating CPS destruction during storage, is less probable the smaller the content of impurities (including mechanical ones) in lithium, the more uniform the pore sizes in the separator material and the more uniform the distribution of concentration of ionic compound (fluoroborate, lithium preparation, etc.) in the bulk separator. 

Figure 10.9. Schematic of the total electric conductivity at different oxygen pressures of an oxidic electrolyte [like case (a) in Figure 10.7]. At extremes in oxygen pressure the compound is an n-type or p-type semiconductor because the mobility of the electronic charge carriers is much higher than that of the ionic charges. When the concentrations of the electronic charge carriers drop below the ionic defect concentrations the compound becomes a mixed conductor. In the electrolytic domain there is no contribution of electrons to the conductivity. From 0. Johannesen and P. Kofstad. Electrical conductivity in binary metal oxides. Part 2. J. Mater. Educ. 7,969 (1985) with permission from the Journal of Materials Education.

Reactions (3) and (4) proceed in solid electrolytes, for instance, in solid solutions based on lanthanum gallate of the general formula Lai.xAxGai.yBy03.(x+yy2(A = Ca, Sr, Ba B = Mg, Zn). These systems have high ionic conductivity caused by high concentration of oxygen vacancies [14, 15] and they are wide gap semiconductors, hence, concentrations of intrinsic electronic defects in these compounds are very low. 

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