Conductivity Change during Replacement of Na(+) by Ag(+) in Polycrystalline Beta Alumina.
Abstract
The longitudal conductivity was determined by a four-probe technique during the replacement of Na(+) ions by Ag(+) ions from the inside of a closed-end tube. Similarly, the radial conductivity was measured during exchange starting from the outside. The conductivity-time curves display a minimum with a conductivity value below that of the Ag Beta alumina. The results also show that the change in conductivity with ion exchange time is steeper than that predicted by various models. The effects likely to produce additional resistances are presented. The experimental work clearly indicates that the distribution of the ion exchanged species is of central importance. As a result, a relatively small amount of ion exchange can exert a large influence on the conductivity. In radial measurements, the replacement of only 20% Na(+) is able to cause conductivity values representative of Ag(+) beta alumina. This behaviour is quite significant for battery applications where cell resistance is measured in the radial direction. The exchange effect is not nearly as dramatic for the longitudinal configuration. In this case parallel resistance paths are available and nearly as dramatic for the longitudinal configuration. In this case parallel resistance paths are available and nearly 50% exchange is necessary before the conductivity of Ag(+) beta alumina is attained.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 1985
- Accession Number
- ADA159528
Entities
People
- Bruce S. Dunn
- M. Breiter
- M. Maly-schreiber
Organizations
- University of California, Los Angeles