Gas Characterization- and Mass Spectrometry-Tools for the Analysis of Aging in Electrical Double Layer Capacitors: State-of-the-Art and Future Challenges

Aging processes occurring in electrical double layer capacitors greatly influence the lifetime of these energy storage devices and an increasing attention has been directed toward their understanding. While most studies approach this topic based on the overall electrochemical performance of the cell (such as enhanced resistance) or the materials degradation, addressing its failure causes at the electrolyte level is of great importance. Doing so, more precise strategies to improve the lifetime and performance can be developed for a wide range of applications. This article provides an overview of the current state of separation tools regarding gas chromatography and detection tools in various combinations with mass spectrometry. The aim of this work is to present the present state of the current knowledge on aging processes, with a focus on gas chromatography and mass spectrometry. Then, an outlook onto the challenges as well as ideas of combining methods is given. Here, the work offers a judgement into future challenges.