Protective coatings on stainless steel bipolar plates for proton exchange membrane (PEM) electrolysers

Kolb

Sata

et al. 2017

Energy Environ. Sci.

Self Cite

159

148

Section: Introductionmentioning

confidence: 99%

Comprehensive investigation of novel pore-graded gas diffusion layers for high-performance and cost-effective proton exchange membrane electrolyzers

Kolb

Sata

et al. 2017

Energy Environ. Sci.

Self Cite

159

148

“…For example, BPPs are manufactured on titanium thanks to its corrosion stability in oxidative environments, but machining this metal is complicate and expensive [16,17]. Recently, coated stainless steel has proven to be an alternative base material for BPPs, showing similar durability than the titanium ones [18,19].…”

Section: Introductionmentioning

confidence: 99%

Durable Membrane Electrode Assemblies for Proton Exchange Membrane Electrolyzer Systems Operating at High Current Densities

Wang

Abouatallah

et al. 2016

Electrochimica Acta

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127

High efficiencies, wide operation range and rapid response time have motivated the recent interest in proton exchange membrane (PEM) electrolysis for hydrogen generation with surplus electricity. However, degradation at high current densities and the associated mechanism has not been thoroughly explored so far. In this work, membrane electrode assemblies (MEA) from different suppliers are aged in a commercial PEM electrolyzer (2.5 N m 3 H 2 h -1 ), operating up to 4 A cm -2 for more than 750 h. In all cases, the cell voltage (E cell ) decreases during the testing period. Interestingly, the cells with Ir-black anodes exhibit the highest performance with the lowest precious metal loading (1 mg cm -2 ). Electrochemical impedance spectroscopy (EIS) shows a progressive decrease in the specific exchange current, while the ohmic resistance decreases when doubling the nominal current density. This effect translates into an enhancement of cell efficiency at high current densities. However, Ir concurrently leaches out and diffuses into the membrane. No decrease in membrane thickness is observed at the end of the tests. High current densities do not lead to lowering the performance of the PEM electrolyzer over time, although MEA components degrade, in particular the anode.

“…These BPPs are expected to have much lower cost than the state-of-the-art Ti-based ones coated with Pt or Au, which are the most expensive component of the stack14. Successive steps of VPS (Ti, 50 μm) and PVD magnetron sputtering (Nb, 1 μm) were employed to deposit Nb/Ti layers on stainless steel substrates.…”

Section: Discussionmentioning

confidence: 99%

Low-Cost and Durable Bipolar Plates for Proton Exchange Membrane Electrolyzers

Wang

Abouatallah

et al. 2017

Sci Rep

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Cost reduction and high efficiency are the mayor challenges for sustainable H2 production via proton exchange membrane (PEM) electrolysis. Titanium-based components such as bipolar plates (BPP) have the largest contribution to the capital cost. This work proposes the use of stainless steel BPPs coated with Nb and Ti by magnetron sputtering physical vapor deposition (PVD) and vacuum plasma spraying (VPS), respectively. The physical properties of the coatings are thoroughly characterized by scanning electron, atomic force microscopies (SEM, AFM); and X-ray diffraction, photoelectron spectroscopies (XRD, XPS). The Ti coating (50 μm) protects the stainless steel substrate against corrosion, while a 50-fold thinner layer of Nb decreases the contact resistance by almost one order of magnitude. The Nb/Ti-coated stainless steel bipolar BPPs endure the harsh environment of the anode for more than 1000 h of operation under nominal conditions, showing a potential use in PEM electrolyzers for large-scale H2 production from renewables.