So far, hydrogen compatibility of polymer materials was investigated, focusing on gaining insight in general degradation mechanisms. However, this is not yet sufficient for purposes of safety and performance requirements, for example, in the automotive industry and especially, the corresponding advanced material development, which needs meaningful and comprehensive data for prospective long time intervals. Therefore, herein, the applicability of forced aging regimes and the suitability of different analytical techniques for clarification of the underlying mechanisms are focused on. The study analyzes the behavior of polyether ether ketone, (thermoplastic) polyurethane and fluoroelastomer materials after prolonged aging in hydrogen atmosphere under pressure as it occurs in hydrogen fuel‐cell vehicles. Material changes are investigated by electron microscopy, thermogravimetry, differential scanning calorimetry, and gas sorption measurements. Especially thermogravimetry turns out to indicate subtle material changes that are important indications for material choice.

Polymeric materials are of crucial importance for the safety of fuel cell vehicles as they are applied for example as seals. The cover illustrates the analysis of polymers subjected to hydrogen aging treatments with the aim to determine the applicability of various characterization techniques and enable reliable and fast material quality control. More details can be found in article number http://doi.wiley.com/10.1002/ente.202200018, Svenja Morsbach, Alexander Börger and co‐workers.