Post‐Mortem Gas Chromatography‐Mass Spectrometry Analysis of Aging Processes in Acetonitrile‐based Supercapacitors

Abstract

An ongoing challenge in the field of supercapacitors revolves around comprehending their failure mechanisms. The aging processes occurring at the electrode/electrolyte interphase of these devices are complex. Thus far, much attention has been directed toward examining the aging of electrodes, while fewer studies have been dedicated to the electrolyte's aging. This study aims to address this point and to gain a deeper understanding of the importance of individual decomposition products on the overall decomposition of the electrolytic solution of electric double‐layer capacitors. Therefore, the decomposition of the state‐of‐the‐art electrolyte 1 m solution of tetraethylammonium‐tetrafluoroborate in acetonitrile and that of the same electrolyte doped with compounds known to form during its aging, such as acetamide, 2,4,6‐trimethyl‐1,3,5‐triazine, and triethylamine has been investigated post‐mortem. The results of this study show that GC‐MS is a useful technique to interpret and understand the degradation processes taking place in the electrolytes of supercapacitors.