Highly concentrated aqueous electrolytes, known as water-in-salt electrolytes, could be an alternative to the organic solvents used in car batteries and other electrochemical devices. Abundance and, hence, low cost are key factors in this application, alongside nontoxicity, according to the review article “Water-in-salt electrolytes for high voltage aqueous electrochemical energy storage devices” published in the journal Current Opinion in Electrochemistry by Vitor Leite Martins and Roberto Manuel Torresi, both of whom are affiliated with the University of São Paulo’s Chemistry Institute (IQ-USP) in Brazil.
The study was conducted as part of Martins’ postdoctoral research supervised by Torresi and part of the Thematic Project “Optimization of the physicochemical properties of nanostructured materials for applications in molecular recognition, catalysis and energy conversion/storage,” for which Torresi is principal investigator. Both projects are supported by FAPESP.
“The term ‘water-in-salt electrolytes’ refers to solutions constituting a very high concentration of salt in a very small amount of water. The amount of water is just sufficient to dissolve the ions to promote solvation. The system contains no free water, unlike conventional solutions,” Torresi told Agência FAPESP.
Read more at São Paulo Research Foundation
Image: The review article by researchers at the University of São Paulo shows the advantages of this technological alternative, which is nontoxic and much cheaper than other methods (transmission electronic microscopy image of sodium dititanium tris(phosphate) before (A e B) and after (C e D) 421 galvanostatic charge and discharge cycles at 0.2 C-rate (full charge/discharge in five hours) / Current Opinion in Electrochemistry). CREDIT: São Paulo Research Foundation