Richard Hanke-Rauschenbach

Enhancing PEM water electrolysis efficiency by reducing the extent of Ti gas diffusion layer passivation

Proton exchange membrane water electrolysis (PEM WE) suffers from several issues, such as the high cost and low stability of the electrolyser unit components. This is especially evident for an anode polarised to a high potential and in contact with an acidic membrane. Such a combination is detrimental to the vast majority of electron-conducting materials. Nowadays Ti (possessing a protective passive layer on its surface) is used as the construction material of an anode gas diffusion layer. Since the passivation layer itself is non-/semiconducting, an excessive degree of passivation leads to high surface contact resistance and to energy losses during PEM WE operation. This problem is usually solved by coating the Ti surface with precious metals. This leads to a further increase of the already very high cell investment costs. In this work an alternative method based on appropriate Ti etching (in acid) is presented. The (surface) composition of the samples treated was investigated using SEM, X-ray fluorescence and diffraction and photoelectron spectroscopy. TiHx was found in the subsurface layer. This was responsible for preventing excessive passivation of the Ti metal. The superior performance of the etched Ti gas diffusion layer (compared to non-etched) in a PEM water electrolyser was confirmed during an (>u2009100xa0h) experiment with current densities of up to 1xa0A cm−u20092. Using the described treatment the surface contact resistance was substantially reduced and its increase during PEM WE operation was largely suppressed. As this method is very simple and cheap, it has tremendous potential for improving PEM WE process efficiency.Graphical Abstract

Effect of the MEA design on the performance of PEMWE single cells with different sizes

In the field of polymer electrolyte membrane water electrolysis (PEMWE), a significant amount of excellent scientific results has been generated during the past decades. However, the comparability and reproducibility of these results between different cell types and different laboratories is not always straightforward. In this contribution, an exemplary ring experiment on the single-cell level compares the performances of three cell types: the differential cell (

Diagnostic concept for dynamically operated biogas production plants

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Current density effect on hydrogen permeation in PEM water electrolyzers

4cm2) and two integral cells: an elongated cell (

Understanding PEM fuel cell dynamics: The reversal curve

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Modelling and Designing Cryogenic Hydrogen Tanks for Future Aircraft Applications

50.4cm×0.45cm) and a circular cell (