A Lithium Salt of a Lewis Acid-Base Complex of Imidazolide for Lithium-Ion Batteries

We report the synthesis of a class of lithium salts in which the two strongly Lewis basic sites of lithium imidazolide are each complexed by the Lewis acid to yield lithium bis(trifluoroborane)imidazolide The anion has a high degree of charge delocalization over the aromatic ring and two four-coordinate boron centers and has only very weakly basic sites on the periphery which keep the coordinating ability to the lithium cation low. The salt has a conductivity of 5.06 mS/cm in 1:3 ethylene carbonate:ethylmethyl carbonate solution and has high oxidative stability. Lithium cells made with common anode and cathode materials using an electrolyte containing this salt had performance similar to cells using an electrolyte containing © 2003 The Electrochemical Society. All rights reserved.