Characterization of Different Conductive Salts in ACN‐Based Electrolytes for Electrochemical Double‐Layer Capacitors

Abstract

Abstract Herein we report a systematic investigation of the chemical and physical properties of acetonitrile‐based electrolytes that contained the salts tetraethylammonium tetrafluroroborate (Et 4 NBF 4 ), tetraethylammonium bis(trifluoromethanesulfonyl)‐ imide (Et 4 NTFSI), 1‐butyl‐1‐methylpyrrolidinium tetrafluoroborate (Pyr 14 BF 4 ), or 1‐butyl‐1‐methylpyrrolidinium bis(trifluoromethanesulfonyl)imide (Pyr 14 TFSI). The ionic conductivity, viscosity, density, and electrochemical stability windows of these electrolytic solutions have been considered in detail. From these results, the electrolyte Et 4 NTFSI (1 mol dm −3 ) in ACN appeared to display a promising set of properties that allow the realization of ACN‐based electrochemical double‐layer capacitors able to display stable behavior at 3.1 V.