Physicochemical Diagnostics and Structure of Molten Salt Electrolytes

 

 

V.A. Khokhlov

 

Institute of High-Temperature Electrochemistry

20 S.Kovalevskaya Str., Ekatherinburg, Russia

 

 

 

Several varieties of actual molten salt electrolytes are considered on the basis of the results of complex physicochemical investigation and a present view of their structure.

 

1. The most commonly encountered and extensively studied electrolytes are the molten salt-solvents with predominating Coulomb interaction between particles. These melts are the suitable subjects to test the various structural models. Processing conditions of the metals and alloys production as well as the electrochemical and thermochemical treatment of materials are controlled for the most part by the properties of salt solvent.

 

2. The ability of typical ionic melts to dissolve the salts of polyvalent metals and to ionize the typical molecular compounds is accompanied as a rule by the formation of the firm complex ions affecting substantially the electrode reactions. Many of these electrolytes are low-melting salt mixtures giving a possibility of performing the electrochemical process at relatively low temperatures.

 

3. The pronounced electronic conductivity is found on dissolving metal or metalloid in ionic melts, which decreases the electrolytic properties of medium but makes possible the carrying out other electrochemical reactions with the participation of the electrons dissolved in molten salt. The existing unusual valence states of polyvalent metal ions is the characteristic feature of such ion-electronic melts, which can change the direction of electrochemical reaction.

 

4. In specific cases, the high electronic conductivity of molten salt electrolyte results from electronic exchange between different valence ions of the same metal or metalloid. Such melts may exhibit a high electrocatalytic activity.  They can be used in the special-purpose chemical power sources.

 

5. As an example of the salt electrolytes known scantily, the ionic melts are considered, in which a manifestation of the hydrogen bond is found.