Ionic conductivity (denoted by ) is a measure of a substance's tendency towards ionic conduction. Ionic conduction is the movement of

ion An ion () is an atom or molecule with a net electrical charge. The charge of an electron is considered to be negative by convention and this charge is equal and opposite to the charge of a proton, which is considered to be positive by convent ...

s. The phenomenon is observed in solids and solutions. Ionic conduction is one mechanism of

current Currents, Current or The Current may refer to: Science and technology * Current (fluid), the flow of a liquid or a gas ** Air current, a flow of air ** Ocean current, a current in the ocean *** Rip current, a kind of water current ** Current (hydr ...

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 β''-alumina ("BASE"), a form of

aluminium oxide Aluminium oxide (or aluminium(III) oxide) is a chemical compound of aluminium and oxygen with the chemical formula . It is the most commonly occurring of several Aluminium oxide (compounds), aluminium oxides, and specifically identified as alum ...

that has channels through which sodium cations can hop. When this

ceramic A ceramic is any of the various hard, brittle, heat-resistant, and corrosion-resistant materials made by shaping and then firing an inorganic, nonmetallic material, such as clay, at a high temperature. Common examples are earthenware, porcela ...

is complexed with a mobile

, such as Na⁺, it behaves as so-called

fast ion conductor In materials science, fast ion conductors are solid conductors with highly mobile ions. These materials are important in the area of solid state ionics, and are also known as solid electrolytes and superionic conductors. These materials are usefu ...

. BASE is used as a

membrane A membrane is a selective barrier; it allows some things to pass through but stops others. Such things may be molecules, ions, or other small particles. Membranes can be generally classified into synthetic membranes and biological membranes. Bi ...

in several types of

molten salt Molten salt is salt which is solid at standard temperature and pressure but liquified due to elevated temperature. A salt that is liquid even at standard temperature and pressure is usually called a room-temperature ionic liquid, and molten salts ...

electrochemical cell An electrochemical cell is a device that either generates electrical energy from chemical reactions in a so called galvanic cell, galvanic or voltaic cell, or induces chemical reactions (electrolysis) by applying external electrical energy in an ...

History

Ionic conduction in solids has been a subject of interest since the beginning of the 19th century.

Michael Faraday Michael Faraday (; 22 September 1791 – 25 August 1867) was an English chemist and physicist who contributed to the study of electrochemistry and electromagnetism. His main discoveries include the principles underlying electromagnetic inducti ...

established in 1839 that the laws of

electrolysis In chemistry and manufacturing, electrolysis is a technique that uses Direct current, direct electric current (DC) to drive an otherwise non-spontaneous chemical reaction. Electrolysis is commercially important as a stage in the separation of c ...

are also obeyed in ionic solids like

lead(II) fluoride Lead(II) fluoride is the inorganic compound with the formula Pb F2. It is a white solid. The compound is polymorphic, at ambient temperatures it exists in orthorhombic (PbCl2 type) form, while at high temperatures it is cubic ( Fluorite type). ...

() and

silver sulfide Silver sulfide is an inorganic compound with the formula . A dense black solid, it is the only sulfide of silver. It is useful as a photosensitizer in photography. It constitutes the tarnish that forms over time on silverware and other silver ob ...

(). In 1921, solid

silver iodide Silver iodide is an inorganic compound with the formula Ag I. The compound is a bright yellow solid, but samples almost always contain impurities of metallic silver that give a grey colouration. The silver contamination arises because some samp ...

() was found to have had extraordinary high ionic conductivity at temperatures above 147 °C, AgI changes into a phase that has an ionic conductivity of ~ 1 –1 cm⁻¹. This high temperature phase of AgI is an example of a superionic conductor. The disordered structure of this solid allows the Ag⁺ ions to move easily. The present record holder for ionic conductivity is the related material . β''-alumina was developed at the

Ford Motor Company Ford Motor Company (commonly known as Ford) is an American multinational corporation, multinational automobile manufacturer headquartered in Dearborn, Michigan, United States. It was founded by Henry Ford and incorporated on June 16, 1903. T ...

in the search for a storage device for

electric vehicle An electric vehicle (EV) is a motor vehicle whose propulsion is powered fully or mostly by electricity. EVs encompass a wide range of transportation modes, including road vehicle, road and rail vehicles, electric boats and Submersible, submer ...

s while developing the

sodium–sulfur battery A sodium–sulfur (NaS) battery is a type of molten-salt battery, molten-salt battery (electricity), battery that uses liquid sodium and liquid sulfur electrodes. This type of battery has a similar energy density to lithium-ion battery, lithium-i ...

References

External links

J Chem Phys
Physical quantities Electrochemistry {{electrochem-stub

In crystalline solids

History

See also

References

External links