Estimation of the surface potential in superionic ozide conductors using the Stern model
The surface potential ΨS and concentration of the surface defects in superionic oxides MIV1-cMeⅢcO2-c/2 were calculated using the Stern model from the given values of the adsorption energies of anion vacancy, ΔG+, and dopant cation, ΔG-. Gouy-Chapman and Mott-Schottky models were employed for taking into account the potential distribution in the space charge layer. The values of ΨS obtained using these two models strongly differ in the low temperature limit and are very close at high temperatures. Therefore, at high temperatures the surface potential does not practically depend on the particular form of the potential gradient and is determined mainly by the adsorption energies of the defects. The values of the surface potential obtained at ΔG+=-0.6 eV and ΔG-=0 eV agree with the experimental conductivity data reported. It was found that the concentration of the MeMs on the surface is elevated in spite of positive surface potential and zero value of the segregation energy, ΔG-. Despite the segregation of cations, the surface as a whole remains positively charged and the diffusion layer is depleted of anionic vacancies.
Space charge Surface potential Stern model Ozide solid electrolytes Segregation
N.F.Uvarov
Institute of Solid State Chemistry and Mechanochemistry SB RAS, Kutateladze 18, Novosibirsk, 630128, Russia
国际会议
The 16th International Conference on Solid State Ionics(第十六届国际固态离子学会议)
上海
英文
783-787
2007-07-01（万方平台首次上网日期，不代表论文的发表时间）