Professor Peter Hall, Department of Chemical & Biological Engineering invites you to attend a guest lecture from Roberto Torresi, Inst Chemistry, Sao Paulo on 'The Role of Ionic liquids in energy conversion.'
LT20, G Floor, Sir Robert Hadfield Building, Portobello Street, University of Sheffield S1 3JD
Please advise your attendance if you are not a student or staff member of the University of Sheffield by email to Sharon Brown at firstname.lastname@example.org
Physicochemical characterization of ionic liquids will be discussed regarding their potential applications as materials for energy conversion and storage applications. Properties as electrochemical window, density, viscosity and ionic conductivity will be presented. The diffusion coefficient was obtained by two different techniques, PGSE-NMR and Li electrodeposition with microelectrodes. In addition, the Li+ transport number was also calculated by the PGSE-NMR technique and by an electrochemical approach. Raman spectroscopy and molecular dynamics simulations were used to evaluate the short-range structure of the liquids. The results found suggest that these Li+ mixtures have promising properties for potential applications as electrolytes in batteries. The polarity and hidrophilicity or lipophilicity can be varied through a suitable choice of the anion. The phosphonium ionic liquids, are thermally stable and they are interesting for use in electrochemical systems. With the strongly electron-withdrawing phosphonium groups, the anion is expected to possess several desirable properties, such as resistance to oxidation and weak cation coordination. All liquids are stable till over 400°C and it is observed that adding the lithium salt, there is an increase in the viscosity and density, but surprisingly a slight increase in the ionic conductivity is observed. This result is unusual compared with other ILs derives from other anions and it shows that it is a promising result considering the application as electrolyte for lithium ion batteries. Finally, we will present some discussion about the scene of energy storage and conversion in Brazil.