Richard Hanke-Rauschenbach

Reducing capital costs is essential for improving the economic viability of proton exchange membrane (PEM) water electrolysis, with bipolar plates (BPPs) representing a significant cost factor. In this study, a novel titanium–polymer composite material is introduced as a cost-efficient candidate for the BPP. The composite consists of low-cost alloyed titanium powder and polyvinylidene fluoride (PVDF) as the polymer matrix and is designed for scalable manufacturing by injection molding. To enhance corrosion resistance and electrical contact under harsh anodic conditions, two Pt-based protective coatings were investigated: a single Pt coating and a Ti+Pt bilayer coating. Short-term electrochemical tests showed that uncoated composite plates exhibit a performance comparable to conventional titanium BPPs; however, long-term stability was limited by contamination originating from impurities of the alloyed powder. While the Pt coating reduced the contact resistance and thus the cell voltage, it did not sufficiently prevent contamination. In contrast, the Ti+Pt coating markedly suppressed contamination and allowed stable operation for 1000 h, although the average degradation rate of 27 µV/h remains relatively high. The results suggest that Ti+Pt‐coated titanium‐polymer composites could be a promising and cost-efficient alternative to full‐titanium BPPs, providing a basis for further coating optimization and the development of scalable manufacturing processes.

1. Hydrogen-powered aviation (henceforth called ‘HPA’) encompasses a set of technologies that enable aircraft to fly using hydrogen as a fuel. It is currently the most radical, technologically dema...

This study assesses the Europe-wide potential for multi-sector integration of water electroly-sis, wastewater treatment plants, and district heating networks, enabling by-product oxygen and waste heat utilization to improve energy efficiency and reduce system costs. Wastewater treatment plants (WWTP) can serve as geographically fixed anchor points for such integra-tion, requiring the consideration of land-use and infrastructure criteria to assess its feasibility. A hybrid methodology narrows the theoretical potential to geospatially and economically via-ble WWTP sites. First, a GIS-based analysis applying energy infrastructure access and land-use criteria (flood risks, protected zones, and space availability) identifies geospatially feasible WWTP sites. Second, an optimization model evaluates site-specific economic viability. Re-sults indicate that multi-sector integration is geospatially and economically viable at multiple European WWTP sites. Deployment is primarily limited by hydrogen pipeline infrastructure access, followed by nature reserves. These criteria reduce an initial set of 197 large-scale WWTPs of at least 500,000 population equivalents to 60 geospatially feasible WWTP sites (30.5%). Of these feasible sites, 35 offer strong district heating integration potential with con-nection distances below 5 km to existing district heating networks. Furthermore, by-product oxygen utilization achieves potential cost reductions between 0.05 and 0.20 EUR/kgH2. Nev-ertheless, overall hydrogen supply costs remain predominantly driven by renewable electricity potentials and financing conditions, with minimum costs achieved in Spain. Realizable poten-tial may be further limited by site-specific factors such as grid capacity, permitting, and land ownership, which are not captured at the European scale of this study.

Hydrogen crossover is a major challenge in anion exchange membrane water electrolysis (AEMWE), affecting both efficiency and operational safety. In this study, the combined effect of cathode feed configuration (wet vs dry cathode) and catalyst-coated substrate (CCS) properties on cell performance and hydrogen crossover are systematically investigated. Two cathode CCS types are evaluated, including a commercially available and an in-house manufactured variant prepared by hand-spraying (0.5 mg cm − 2 Pt), using identical anodic CCS. The in-house CCS delivers improved cell performance in wet cathode configuration (1.79 V at 3 A cm − 2 ) but leads to more than doubled hydrogen to oxygen (HTO) content compared to the commercial CCS (0.71 vs 0.29 vol%). Switching from wet to dry cathode configuration results in a significant reduction of HTO for both CCS types, while cell performance is only slightly affected. These findings highlight the importance of considering both cell voltage and hydrogen crossover when optimizing electrolyte feed strategy and cathodic catalyst layer design.