Higher performance with electrolysis technology
The project LastEISy materials for catalysts and membranes, and so-called interconnectors to be interactively improved. Interconnectors connecting the anode and cathode of the fuel cell electrically and thermally and distribute the fuel gas and air in the system. Currently, researchers rely on a test stand , the test new catalysts and membranes. Thereafter, the structure and various materials are to be investigated ex situ.
|Project status||Project completed|
|Efficiency AC/VN H2||> 80 %|
|Project duration||June 2012 until December 2015|
The project is structured by an iterative improvement of materials for interconnectors, catalysts and membranes. So far, the focus was on the development of long-term stable, yet inexpensive interconnectors. Here, a great success was achieved due to the extensive replacement of titanium through cost-effective stainless steel. In the meantime, a test stand is being built that allows us to test new catalyst (mixtures) and membranes. In a first step, we will perform reference measurements with already commercially available catalysts with different loadings and membrane thicknesses. Based on this, different materials are then examined in operation and ex situ.
In this project, novel materials for use in PEM electrolysis systems are being developed and tested under realistic conditions in the frame of a partnership of industry and academia. The development areas include both MEAs and catalysts as well as the interconnectors. By measurements during operation and ex situ using imaging and spectroscopic methods, the influence of different, realistic operational profiles on performance and long term stability is to be analyzed. In addition, the influence of the BoP components will be tested. The experiments will be accompanied by modeling activities, in order to reproduce and explain the degradation observed in the experiments with the aim to optimize improvements in material selection and operation.
In connection with the increasing installed capacity of fluctuating renewable energy, storage technologies for electric power are increasingly becoming the focus of industrial and political interest. A promising possibility are chemical storage technologies, such as hydrogen storage, associated with the production of hydrogen from (preferably renewable) electricity using water electrolysis. This allows us to store large amounts of oversupply of electrical energy, e.g. from wind turbines, as hydrogen. The stored hydrogen can then either be re-converted back at a later time or be directly recycled as fuel for the transport sector, as a chemical feedstock or for household energy use by mixing it into the natural gas grid.
Compared to alcaline electrolysers, PEM electrolyzers promise economic advantages due to their size and rapid response rate if they achieve a similar durability as the alkaline electrolyzers. Currently, the drawback is that the catalyst layers in the electrodes of the PEM electrolysis cells degrade faster at varying load requirements than in the alkali electrolysis. Therefore, the goal of this project is to improve the catalyst layers in respect to their durability under changing load conditions and to better understand the processes involved in the degradation.
In this project, improvements in the performance and durability of electrolysis cells and stacks, as well as the overall system, will be sought in basic experiments. This includes both material development (interconnectors, membranes, catalysts) as well as improvements in procedural system operation. The optimizations that can be achieved in this project should then be transferred to large power plants as part of other projects.8 In this project, improvements in the performance and durability of electrolysis cells and stacks, as well as the overall system, will be sought in basic experiments. This includes both material development (interconnectors, membranes, catalysts) as well as improvements in procedural system operation. The optimizations that can be achieved in this project should then be transferred to large power plants as part of other projects.
- DLR - part 1a - Installation of an electrolyzer test system
First, a test stand for an electrolyzer is built up, in which further experimental work can be performed. The system is designed for a stack of cells that have an active area of about 100 cm2. So they do not correspond to the geometry of the MW system. However, qualitative statements about cell characteristics at varying material parameters can be made sufficiently. Also important in planning the test stand is the dimensioning of the BoP components, as they have a large influence on the performance and long term stability of the system.
- DLR - part 1b - Operation of an electrolyzer with different MEA configurations
In this part of the project, the stacks developed by Hydrogenics in sub-project 2 are investigated experimentally in operation and ex situ. Especially the latter method provides important conclusions about structural changes in the catalyst layers, as well as chemical changes. With this knowledge, conclusions about the behavior of the catalyst layers can be obtained, which can then lead to a reconfiguration of catalyst materials.
- DLR - part 1c - Dynamic degradation tests
First, realistic, intermittent renewable energy representing dynamic load profiles are being developed in partnership with Hydrogenics. Then, the electrolyzer is operated in accordance to these profiles. The goal of this part of the project is, beside findings on material development, the study of the influence of BoP components of the entire system on performance and durability of the electrolyzer.
- DLR - part 1d - Modeling of the degradation
The experimental investigations will be accompanied by the development of a numerical model that is able to reproduce the degradation mechanisms in the electrolysis cells. This model includes both findings of the operation and the ex situ studies. The aim is to keep the model as generic as possible in order to derive universal knowledge.
- Hydrogenics - part 2a - Build-up of a PEM electrolyzer stack
Based on material tests of DLR, Hydrogenics will develop stacks and perform basic tests for usability.
- Hydrogenics - part 2b - Definition and monitoring of the dynamic tests
In cooperation with DLR the conditions and test procedures for the dynamic tests of the electrolyzer are set.