Robert Steinberger-Wilckens

A simple approach for PtNi–MWCNT hybrid nanostructures as high performance electrocatalysts for the oxygen reduction reaction

We report a simple one-pot synthesis of PtNi–MWCNT hybrid nanostructures as a high performance and durable electrocatalyst for the oxygen reduction reaction (ORR) in polymer electrolyte fuel cells (PEFCs). The whole approach was achieved in aqueous solution at room temperature, without using any organic solvents, templates or growth inducing catalysts. A single-crystal Pt nanoparticle was successfully grown on Ni nanoparticle surfaces using commercial Ni-coated MWCNTs as a support. PtNi–MWCNT hybrids possessed a high mass activity of 0.51 A mgPt−1, nearly double that of the state-of-the-art TKKs Pt/C catalyst. After an accelerated durability test by 2500 potential sweeping cycles, PtNi–MWCNTs still retained 89.6% of their initial mass activity, which is 0.46 A mgPt−1 and 4% higher than the DOE (Department of Energy) target of 0.44 A mgPt−1 for 2017–2020. The reported synergy between high performance and simple synthesis demonstrated that PtNi–MWCNTs could be effective cathode catalysts for high performance PEFCs.

Plasma nitriding induced growth of Pt-nanowire arrays as high performance electrocatalysts for fuel cells

In this work, we demonstrate an innovative approach, combing a novel active screen plasma (ASP) technique with green chemical synthesis, for a direct fabrication of uniform Pt nanowire arrays on large-area supports. The ASP treatment enables in-situ N-doping and surface modification to the support surface, significantly promoting the uniform growth of tiny Pt nuclei which directs the growth of ultrathin single-crystal Pt nanowire (2.5–3 nm in diameter) arrays, forming a three-dimensional (3D) nano-architecture. Pt nanowire arrays in-situ grown on the large-area gas diffusion layer (GDL) (5 cm2) can be directly used as the catalyst electrode in fuel cells. The unique design brings in an extremely thin electrocatalyst layer, facilitating the charge transfer and mass transfer properties, leading to over two times higher power density than the conventional Pt nanoparticle catalyst electrode in real fuel cell environment. Due to the similar challenges faced with other nanostructures and the high availability of ASP for other material surfaces, this work will provide valuable insights and guidance towards the development of other new nano-architectures for various practical applications.

Cathodic materials for intermediate-temperature solid oxide fuel cells based on praseodymium nickelates-cobaltites

A unique combination of methods (TPD of O2, thermogravimetry, isotopic heteroexchange of oxygen in different modes) was used to carry out detailed studies of oxygen mobility and reactivity in mixed praseodymium nickelates-cobaltites (PrNi1 − xCoxO3 + δ) and their composites with doped cerium dioxide (Ce0.9Y0.1O2 − δ) as promising cathodic materials stable towards the effect of CO2 in the intermediate-temperature region. It is shown that in the case of composites of PrNi1 − xCoxO3+δ-Ce0.9Y0.1O2 − δ synthesized using the Pechini method and ultrasonic treatment, stabilization of the disordered cubic perovskite phase due to redistribution of cations between the phases provides high oxygen mobility. Preliminary results on tests of cathodic materials of this type supported on planar NiO/YSZ anodes (H.C. Starck) with a thin layer of YSZ electrolyte and a buffer Ce0.9Y0.1O2 − δ layer showed that power density of up to 0.4 W/cm2 was reached in the region of medium (600–700°C) temperatures, which was close to typical values for fuel cells of this type with cathodes based on strontium-doped perovskites and their composites with electrolytes.

Innovations in fuel cell technologies

Introduction Micro-applications and -systems Temperature trends Novel fuels Heat utilisation and upscaling Modelling and lifetime prediction Hydrogen generation and reversible fuel cells Outlook

Real-SOFC - A Joint European Effort to Improve SOFC Durability

The Integrated Project Real-SOFC joined 26 partners from throughout Europe active in SOFC technology. The project was funded by the European Commission within the 6th Framework Programme and aimed at improving the durability of planar SOFC stacks to degradation rates of well below 1% per 1000 hours of operation. This is an essential requirement in gaining access to the market for stationary applications. The underlying idea was to improve materials and materials processing on the basis of extensive test results identifying degradation mechanisms, and then to supply industrial components of enhanced quality for repeated testing analysis. This ‘feedback loop’ resulted in ‘2 nd ’ and ‘3 rd ’ Generations of SOFC components. This paper summarises the project approach, shows examples of the major results and of longterm durability testing.

Not cost minimisation but added value maximisation

Fuel cells are on the verge of market entry aiming at replacing long established conventional electricity generation and propulsion technologies. Upon entrance to the first markets the necessarily higher costs will need to be offset by added value to the consumer. Examples, discussed here, indicate that generally speaking the highest additional cost margins will be achievable through lifestyle oriented issues, recreational applications and from remote power. Fuel cells potential environmental superiority results in a high acceptance in public opinion, but, needs to be clearly proven in all aspects from fuel supply to operation and recycling. Only if the added value and environmental performance are convincingly displayed will fuel cells be able to claim a substantial part of their potential market.

Real-SOFC – A Joint European Effort in Understanding SOFC Degradation

The Integrated Project Real-SOFC joins 26 partners from throughout Europe active in planar SOFC technology. The project is funded by the European Commission within the Sixth Framework Programme and aims at improving the understanding of degradation in SOFC stacks and extending the durability of planar SOFC devices such that they become viable for stationary applications. The project consortium comprises of universities, research institutions and industrial companies. The project concept is based on improving materials and materials processing by the provision of extensive test results allowing the identification of degradation mechanisms, and then to supply industrial components of enhanced quality for repeated testing analysis. An iterative programme of component development is employed resulting in the production of ‘2nd’ and ‘3rd’ generations of SOFC components/stacks. This paper offers some recent results on the degradation issues and covers selected aspects of other project-related output such as testing conditions, environmental impact assessment and educational activities.

Recent Results of Stack Development at Forschungszentrum Jülich

Since the mid-nineties several generations of SOFC stacks have been designed and tested incorporating the anode substrate-type cells developed in Julich. The 6th generation, the so-called F-design stacks, with metallic interconnect has been the ‘work horse’ used for testing materials, cells and manufacturing processes in cell and stack development since its introduction in the year 2001. Stacks with up to 60 layers have been operated in recent years, delivering up to 13 kW of electric power. The ferritic parts are made of the commercial steel type CroFer22APU.

European SOFC R&D - Status and Trends

The European Commission has across the past 20 years followed a stringent and sustained funding strategy for hydrogen and fuel cell technology (1). Scope and ambition have been steadily increased in order to drive technology and developers forward to the final goal of market entry and commercialisation. Albeit this commitment, the position of European fuel cell developers in comparison to world standards is not the strongest. Both Japan and the U.S. apparently pursue a more market and engineering oriented approach. Fuel cell technology was invented in Europe in the mid 19th century, but this has – of course – not resulted in a continued leading edge in fuel cell development. Rather, the space programme in the U.S. grasped the opportunities fuel cells offered and turned them into one of the vital elements of life support systems.

SOFC Worldwide — Technology Development Status and Early Applications

Solid Oxide Fuel Cells (SOFC) of various types and designs have been developed world wide through the last two decades. They offer interesting advantages over other fuel cell types, but also have inherent materials problems that have caused a slower development pace as, for instance, compared to the low temperature Polymer Electrolyte Fuel Cell (PEFC). Due to their high operating temperature in the range of 700 to 1000°C, SOFC can be used with a variety of fuels from hydrogen to hydrocarbons with a minimum of fuel processing, can be coupled with gas turbines for the highest electrical system efficiency known in power generation, deliver process heat in industrial applications or supply on-board electricity for vehicles, to name but some typical applications. This report summarizes the more prominent SOFC development strands and gives an overview of the achievements of the various R&D groups. The analysis includes a benchmark that attempts to compare cell and stack characteristics on a standardized basis.