Doctorant H/F-Thin films generated by Atomic Layer Deposition and their integration in PEM (Proton...

The gas phase deposition technique that will be implemented is the so-called Atomic Layer Deposition (ALD) [3], which allows to generate thin film materials coatings of controlled tchickness, chemical nature and structural properties. Once the deposition process optimized, the thin films will be systematically characterized by spectroscopic ellipsometry, X-ray diffraction (XRD), electron microscopy (SEM/TEM) and X-ray photoelectron spectroscopy (XPS). The anti-corrosion properties of the resulting coatings will be evaluated by electrochemical techniques (cyclic voltammetry, electrochemical impedance spectroscopy, Tafel analyses,…). The thin films will be subsequently deposited on structural elements (BPP and PTL) of PEM electrolyzers and implemented in small electrolysis cell (5 cm2) as well as in large devices (25 à 250 cm2) [4].

References :

[1] S. Lædre et al., Int. J. Hydrogen Energy. 42 (2017) 2713–2723.
[2] S. Stiber et al., Energy Environ. Sci. 15 (2022) 109
[3] M. Bechelany et al., Chem. Mater. 30 (2018) 7368–7390.
[4] L. Assaud et al., Renew. Sustain. Energy Rev. 133 (2020) 110286.

Proton Exchange Membrane (PEM) electrolysis is a low temperature technology that produces decarbonized hydrogen from water at low temperature (< 100°C). In addition to better yields compared to the competing technologies, namely alkaline electrolysis (AE), It is one of the only technologies that can be directly coupled to renewable energy sources (solar, wind) which present frequent and high amplitude variations of the delivered power. The current limitations of PEMs concern the porous transport layers (PTL) and the bipolar plates (BPP) which are most often made of titanium because of its resistance against corrosion under the operating conditions of electrolysis [1,2]. However, the highly oxidizing environment of the anode generates a thick oxide layer that develops on the surface of the titanium, resulting in a significant increase of the contact resistance between the elements and affecting the overall efficiency of the electrolysis process, while accounting for more than 50% of the cell costs. Thanks to a multidisciplinary and innovative approach, this project aims at removing one of the main technological barriers of PEM water electrolysis, i.e. the replacement of expensive titanium by stainless steels (316L) - more cost-effective and more easily machinable - for BPPs and PTLs that will be coated with innovative protective layers produced by industry-scalable techniques.