abstract
Modifications of the e.m.f, and faradaic efficiency techniques, taking into account electrode polarization in the measuring cells, in combination with the use of electrodes having sufficiently high polarization resistances enable a precise determination of minor electronic contributions to the conductivity of solid electrolytes. These methods were used to determine the p-type conductivity of compositions based on La(Sr)Ga(Mg)O(3-delta)(LSGM) and Ce(Gd)O(2-delta) (CGO) at 900-1270 K. The oxygen ion transference numbers of these materials under oxygen/air gradient vary in the range 0.999-0.970, increasing with decreasing temperature. Substitution of 2 % gadolinium in Ce(0.80)Gd(0.2)O(2-delta) with praseodymium was found to increase the electron-hole conduction by 2.5 - 4 times. At temperatures above 700 K, both the partial oxygen ionic and p-type electronic conductivities of LaGaO(3)-based phases are higher than those in CGO. The electron-hole transport in LSGM tends to increase with the magnesium concentration, while the activation energy is essentially independent of composition. Electronic conduction in CGO and LSGM electrolytes was also found to be influenced by the ceramic microstructure.
subject category
Chemistry; Electrochemistry; Physics
authors
Kharton, VV; Yaremchenko, AA; Viskup, AP; Figueiredo, FM; Shaulo, AL; Kovalevsky, AV; Naumovich, EN; Marques, FMB
our authors
Aleksey Yaremchenko
Principal Researcher
Andrei Kavaleuski
Principal Researcher
Fernando Manuel Bico Marques
Full professor
Filipe Miguel H Lebre R Figueiredo
Principal Researcher