View source for Ionic conductivity (solid state)

[[File:Superionic ice conducting.svg|thumb|A [[proton conductor]] in a static [[electric field]].]]

'''Ionic conductivity''' (denoted by {{math|''λ''}}) is a measure of a substance's tendency towards '''ionic conduction'''. Ionic conduction is the movement of [[ion]]s.  The phenomenon is observed in solids and solutions. Ionic conduction is one mechanism of [[current (electricity)|current]].<ref>Richard Turton. (2000).The Physics of Solids. New York:: Oxford University Press. {{ISBN|0-19-850352-0}}.</ref> 

==In crystalline solids==
In most solids, ions rigidly occupy fixed positions, strongly embraced by neighboring atoms or ions.  In some solids, selected ions are highly mobile allowing ionic conduction. The mobility increases with temperature.  Materials exhibiting this property are used in batteries. A well-known ion conductive solid is [[Beta-alumina solid electrolyte|β<nowiki>''</nowiki>-alumina]] ("BASE"), a form of [[aluminium oxide]] that has channels through which sodium cations can hop. When this [[ceramic]] is complexed with a mobile [[ion]], such as [[Sodium|Na]]<sup>+</sup>, it behaves as so-called [[fast ion conductor]].  BASE is used as a [[semipermeable membrane|membrane]] in several types of [[molten salt]] [[electrochemical cell]].<ref name="Lu et al. 2010">{{cite journal |doi=10.1016/j.jpowsour.2009.11.120|title=Advanced materials for sodium-beta alumina batteries: Status, challenges and perspectives|year=2010|last1=Lu|first1=Xiaochuan|last2=Xia|first2=Guanguang|last3=Lemmon|first3=John P.|last4=Yang|first4=Zhenguo|journal=Journal of Power Sources|volume=195|issue=9|pages=2431–2442|bibcode=2010JPS...195.2431L}}</ref> 

===History===
Ionic conduction in solids has been a subject of interest since the beginning of the 19th century. [[Michael Faraday]] established in 1839 that the laws of [[electrolysis]] are also obeyed in ionic solids like [[lead(II) fluoride]] ({{chem2|PbF2}}) and [[silver sulfide]] ({{chem2|Ag2S}}). In 1921, solid [[silver iodide]] ({{chem2|AgI}}) was found to have had extraordinary high ionic conductivity at temperatures above 147&nbsp;°C, AgI changes into a phase that has an ionic conductivity of <!--number and units needs fixing-->~ 1 –1&nbsp;cm<sup>−1</sup>. This high temperature phase of AgI is an example of a [[superionic conductor]]. The disordered structure of this solid allows the Ag<sup>+</sup> ions to move easily. The present record holder for ionic conductivity is the related material Ag<sub>2</sub>HgI<sub>4</sub>.<ref>{{Greenwood&Earnshaw2nd|page=800}}</ref> β<nowiki>''</nowiki>-alumina was developed at the [[Ford Motor Company]] in the search for a storage device for [[electric vehicle]]s while developing the [[sodium–sulfur battery]].<ref name="Lu et al. 2010"/>

==See also==
* [[Lattice energy]]
* [[Fast ion conductor]]
* [[NASICON]]

==References==
<references/>

==External links==
* [http://scitation.aip.org/content/aip/journal/jcp/1/7/10.1063/1.1749319 J Chem Phys]

{{DEFAULTSORT:Ionic Conductivity}}
[[Category:Physical quantities]]
[[Category:Electrochemistry]]


{{electrochem-stub}}