Simultaneous ionomer and iridium recycling

This topic aims at simultaneously recycling Ir and ionomers after catalyst-coated membrane (CCM) separation from the PEMWE stack at the EoL and/or from scraps and waste. The novelty and contribution of this topic is to understand the impact of the separation process of the waste stream on the ionomer and PGMs (possible impurities, degradation of the polymer’s molecular structure, change in physical/chemical properties, performance, etc.). This fundamental understanding of material degradation is crucial for optimising their quality before their re-use in PEMWE cells to ensure sustainable circularity. Recycling efforts are also being pursued in projects, such as SUSTAINCELL[[SUSTAINCELL's primary goal is to recycle ionomer and precious group metals (PGM) sourced from end-of-life cells, membrane electrode assemblies (MEAs), scraps, and waste. They are also focused on implementing eco-design principles and environmentally-friendly manufacturing methods to develop new materials and architectures. Additional information at https://cordis.europa.eu/project/id/101101479]] and BEST4Hy[[Best4Hy aimed at achieving a platinum recovery rate of ≥80% via a hydrometallurgical process and an ionomer recovery of ≥80% via an alcohol dissolution process. Additional information at https://cordis.europa.eu/project/id/101007216]]. The critical difference is that the BEST4Hy project targets fuel cell technologies and platinum only, while this topic focuses on PEMWE technology, specifically addressing the recycling of Ir and the ionomer. Further, the project funded by this call can contribute to and be complemented by EU-funded projects on sustainable hydrogen production, such as CLEANHYPRO[[The primary objective of the project is to develop and organise a sustainable Open Innovation Test Bed (OITB) for electrolysis materials and components, providing a network of facilities and services through a Single Entry Point (SEP). Additional information at https://cordis.europa.eu/project/id/101091777]] and H2SHIFT[[H2SHIFT’s primary focus is to create an innovation and excellence center for innovative hydrogen production technologies open to start-ups and small to medium-sized enterprises from Europe and around the world. Additional information at https://cordis.europa.eu/project/id/101137953]]. CLEANHYPRO could facilitate (partial) testing within the scope of the open innovation test bed whereas H2SHIFT could complement in the need of a techno-economic analysis.

The scope of the project should include:

• Development of new measurement technologies for characterising the degradation state of ionomer in both the PEM and the electrocatalytic layers;
• Assessment of physical-chemical properties of membranes from recycled ionomer and mesoscale morphology;
• Development of new methods to separate the ionomer;
• Manufacturing of CCMs with Ir and recycled ionomer from production waste, and assessment of their beginning-of-life performance and durability via accelerated stress tests (ASTs) in PEM water electrolysis single cell or short stacks (>1000 hrs cell test and comparison to a short stack comprising of a virgin ionomer membrane)[[EU harmonised accelerated stress testing protocols for low-temperature water electrolyser, https://publications.jrc.ec.europa.eu/repository/handle/JRC133726]];
• Evaluation and demonstration of the feasibility of the developed recycling processes through techno-economic analysis and life cycle assessment;
• Evaluation of the possibility of mixing different ionomers (e.g., recycled ionomer with virgin ionomer, different chemistries, etc.) for their application in catalyst layers, membranes, and alternative applications;
• Manufacturing and testing of membranes from a blend of fluoropolymers from different sources in PEMWE cells, focusing on hydrogen gas crossover, performance and tolerance to accelerated ageing;
• Evaluation of the performance of recycled ionomer in a laboratory scale environment (e.g. 0.5-10 grams of ionomer); in-situ cell testing and ex-situ testing (scanning electron microscopy, thermogravimetric analysis, tensile testing, swelling behaviour in water, equivalent weight (EW), study of the electrical response) compared to virgin ionomer;
• Evaluation of the quality of production waste and EoL ionomer batches (e.g. 50-500 g) by:
  • Using the recycled ionomer in the catalyst layer and membrane of PEMWE cells;
  • Analysing of ionomer performance both ex-situ and in cells with accelerated stress testing;
  • Developing new measuring methods for determining ionomer degradation state;
  • Enable short stack testing for at least 1000 h comprising of the recycled ionomer.
• Verifying the purity of the recycled Ir in collaboration with industrial partners. A purity for Ir of ≥99.9% should be achieved;
• Verifying the quality and performance of recycled iridium from new recycling methods
• Assessing alternative applications of the recycled ionomer;
• Development of pre-processing guidelines for the input materials (granulation, extraction, homogenisation etc.) to reduce the recycling time and enhance efficiency;
• Providing advice on stack design considerations to improve the recyclability of ionomer by allowing better separation of CCMs from the stack and ionomer from the CCM;
• Industrial methods for making membranes and CCMs of the EoL ionomer with the ability to run short stack testing.

For the success of the project funded by this call, the project consortium should have access to end-of-life PEMWE components (e.g., cells, MEAs, CCMs) to evaluate real industrial waste and ensure the practical applicability of the developed solutions.

Proposals are expected to build further on the findings and targets of previous projects and find synergies with running projects (namely the projects mentioned above), as well as with the recently established Innovative Materials for EU Partnership.

For additional elements applicable to all topics please refer to section 2.2.3.2.