A new family of anion receptors and their effect on ion pair dissociation and conductivity of lithium salts in non-aqueous solutions

Abstract

A new family of anion receptors based on aza-ether compounds have been synthesized. Since the anion complexation of these compounds is not based on either positively charged sites or hydrogen bonding, they have a potential to be used in lithium batteries as electrolyte additives. When these compounds are added to non-aqueous electrolytes with lithium salts, such as LiCl/THF or LiBr/THF, the ionic conductivity can be dramatically increased. Near edge X-ray absorption fine structure (NEXAFS) spectroscopy studies show that Cl− anions are complexed with the nitrogen groups in these compounds. The increase in ionic conductivity and the degree of complexation, are both related to the number of R = CF3SO2 groups that are used to substitute the amine hydrogen atoms in these aza-ether compounds.