elastolox - Elastomers for electrolysis and fuel cells

Identify materials, evaluate their durability and understand dependencies

Electrochemical converters (e.g. electrolyzers, fuel cells) play a crucial role in the hydrogen economy. The harsh (e.g. acidic or alkaline) operating conditions present in such systems pose a significant challenge for the materials used. Polymers and plastics can be found in both electrochemically active components (e.g. membranes, electrodes, bipolar plates, etc.) and structural elements (e.g. seals, housings, etc.). The fluoropolymers, applied because of their chemical, thermal and electro(chemical) resistance, are currently facing an uncertain future in light of the PFAS restriction proposal of the European Chemicals Agency (ECHA). In addition, the phase-out of fluoropolymers by manufacturers in the future is also expected to result in limited availability of classic fluoropolymers manufactured with fluorinated surfactants. Instead, fluoropolymers based on fluorine-free surfactants are being manufactured and brought to market. Alternative fluorine-free polymers, sometimes coated, are also currently being considered as potential substitute materials. Therefore, there is a need to identify alternative materials and evaluate them in terms of their resistance in an alkaline environment and oxygen atmosphere and their mechanical properties.

Project priorities & approach

• Definition of the individual requirements of the participants with regard to the materials and consolidation of the core requirements for the subsequent research phase
• Research and evaluation of the scientific literature, technical literature and the market, in particular with regard to the following questions:
  
  • What studies (methods/material behavior) on chemical and/or thermal resistance of elastomer samples in lye/O₂ exist? The focus is on material properties (in terms of resistance, service life properties) under different conditions (e.g. O₂ partial pressure/concentration, lye concentration and temperature).
  • Which possible materials are available on the market (e.g. fluoropolymers, manufactured without fluorine-containing surfactants, alternative fluorine-free elastomers)?
• Definition and production (mixing, vulcanization and pressing/punching) or procurement and/or provision of samples from the participants for the following experimental project phase; definition of the storage conditions depending on the medium (concentration of lye), O₂ pressure and temperature (max. 18 variations of possible storage constellations)
• Setup of the test environment under the specified conditions for an initial selected material (with a storage time of at least 500 h). Characterization of the properties (hardness, dimensional and mass change, compression set, tensile behavior) before and after storage to investigate possible method-related scattering of the test results
• Iteration of the storage tests (including characterization) under defined storage conditions and with defined materials (taking into account the knowledge gained) to determine the most suitable materials for the respective requirements