Recent Research on Electrolyte Solutions

Research on the electrolyte solution is generally focused on one of three areas functional electrolyte additives, flame-resistant or nonflammable electrolyte solutions, and new electrolyte salts. 

Functional electrolyte additives are included in the electrolyte solution to improve battery performance. This concept has been around for some time, tind the basic technology is well established. One early example is the addition of propane sultone to the nonaqueous electrolyte solution of a rechargeable battery using a metallic lithium anode. Although this technology was initially developed for metallic lithium batteries, the use of such additives for LIBs began around 1994. Since then a wide range of additives have been developed. So many different compounds have been used as additives that they are too numerous to mention, but notable examples include vinylene carbonate, propane sultone, phenylcyclohexane, and fluoroethylene carbonate. The selection of additives and determination of their appropriate formulations have become a key aspect of the proprietary know-how of each battery manufacturer, and the search for new additives continues apace. 

The second area of research is flame-resistant or nonflammable electrolyte solutions. The main approach is to employ phosphate compounds in some way, either by using cyclic phosphoric acid ester as solvent or by adding a phosphazene compound as flame retardant. The next most common approach is to use halogen compounds, especially fluorine compounds such as fluorocarbon ester and fluorinated ether, as solvent. There is also the concept of a new safety mechanism whereby a flame retardant is encased in microcapsules to be released in case of battery malfunction. 

Lithium bis(trifluoromethylsulfonyl) amide Lithium bis(pentafluoroethylsulfonyl) amide 

Lithium perfluorinated boric acid salt cluster 

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