Solvent-free molten salts electrolyte

The use of solvent-free electrolytes, i.e., high temperature ionic liquids (molten salt) electrolytes, which only become ionically conductive upon melting when heated to high temperatures. Another variant is the use of low rate, room temperature solid electrolytes. 

Kubota, K. Matsumoto, H., Investigation of an Intermediate Temperature Molten Lithium Salt Based on Fluorosulfonyl(trifluoromethylsulfonyl)amide as a Solvent-Free Lithium Battery Electrolyte, /. Phys. Chem. C, 2013,117, 18829-18836. 

The electrolyte usually consists of a solution of salts, acids or bases in water or protic solvents, such as alcohols, carboxylic acids, etc. [1]. Pure solvents, too, can act as electrolytes if enough conductivity by autodissociation is produced (water, methanol, ethanol, etc.). Moreover, molten salts constitute electrolytes with sometimes extremely high conductivity. It is important to state that the electrolyte should be free from any electronic conductivity othervdse no electrochemical reaction will occur at the electrode/electrolyte interface. 

Electrolytes are distinguished from pure electronic conductors by the fact that the passage of an electric current is only insured by displacement of charged species called ions and hence accompanied by a transfer of matter. Therefore, electrolytes are entirely ionic electrical conductors without exhibiting any electronic conductivity (i.e., no free electrons). They can be found in the solid state (e.g., fluorite, beta-aluminas, yttria-stabilized zirconia, and silver iodide), liquid state (e.g., aqueous solutions, organic solvents, molten salts and ionic liquids), and gaseous state (e.g., ionized gases and plasmas). The ions (i.e., anions or cations)... 

Solvent-free electrochemical fluorination is an alternative method for preventing anode passivation and acetoamidation [18, 19]. As already mentioned, handling extremely corrosive and poisonous anhydrous HF in a laboratory setting is accompanied by serious hazards and experimental difficulties. Molten salts such as 70 % HF/pyridine (Olah s reagent) and commercially available EtaN-SHF [20] are often used to replace anhydrous HF. Other molten salts with the general formula R4NF-nHF (n > 3.5, R = Me, Et, and n-Pr) are useful in selective electrochemical fluorination. These electrolytes... 

Many think the future moves toward solvent free systems Scrosati presents a chapter on polymer electrolytes, most of which are solvent-containing gel-polymers in practical systems, and Nishi discusses gel-polymer battery properties and production. Webber and Blomgren give extensive treatment of ionic hquids (otherwise known as ambient-temperature molten salts) and their use in lithium-ion and other battery systems. 

However, in many situations, water is hardly the ideal solvent. Take the electrolytic production of sodium metal, for exanple. If an aqueous solution of a sodium salt is taken in an electrolytic cell and a current is passed between two electrodes, then all that will happen at the cathode is the liberation of hydrogen gas there will be no electrodeposition of sodium (see Chapter 7). Hence, sodium cannot be electrowon from aqueous solutions. This is why the electrolytic extraction of sodium has taken place from molten sodium hydroxide, i.e., from a medium free of hydrogen. This ... 

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