Influence of the Anion on the Formation of Amorphous Ionically Conducting Lithium Salt Complexes with 18-C-6 and 2.2.2-Cryptand Macrocycles

Abstract

Complexes of lithium salts LiCF 3 SO 3, LiI, LiCH 3 CO 2, LiBF 4, LiSCN, and Li[R−NSO 2 CF 3 ] with the macrocyclic ligands 18-C-6 and 2.2.2-cryptand were examined by differential scanning calorimetry, infrared and Raman spectroscopy, and complex impedance. The formation of an amorphous phase appears to be facilitated by the presence of an unsymmetrical anion containing an ether oxygen of the type [R−NSO 2 CF 3 ] - . An X-ray crystal structure was determined for Li[CF 3 SO 2 N(CH 2 ) 2 OCH 3 ]; these data and that for the previously reported Li[CF 3 SO 2 N(CH 2 ) 3 OCH 3 ] structure was correlated with the physical properties of their 18-C-6 and 2.2.2-cryptand complexes.