The effects of cationic impurities on the performance of proton exchange membrane water electrolyzer

Li, Na; Araya, Samuel Simon; Cui, Xiaoti; Kær, Søren Knudsen

doi:10.1016/j.jpowsour.2020.228617

Cited by 31 publications

(25 citation statements)

References 43 publications

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“…25 Moreover, in addition to general thermal activation, metal impurities in the catalyst layers, which were found to be higher in cell 2, promote radical formation and therefore membrane degradation. 22 It has been reported that fluoride ions in the ppm range can destroy titanium oxide and release Ti ions. [71][72][73] The Ti ions are Fenton active, promoting radical formation which would constitute an autocatalytic degradation mechanism that agrees well with high Ti dissolution rates at elevated temperature operation observed in this work.…”

Section: T [°C]mentioning

confidence: 99%

Understanding Degradation Effects of Elevated Temperature Operating Conditions in Polymer Electrolyte Water Electrolyzers

Garbe

Futter

Agarwal

et al. 2021

J. Electrochem. Soc.

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The cost of polymer electrolyte water electrolysis (PEWE) is dominated by the price of electricity used to power the water splitting reaction. We present a liquid water fed polymer electrolyte water electrolyzer cell operated at a cell temperature of 100°C in comparison to a cell operated at state-of-the-art operation temperature of 60°C over a 300 h constant current period. The hydrogen conversion efficiency increases by up to 5% at elevated temperature and makes green hydrogen cheaper. However, temperature is a stress factor that accelerates degradation causes in the cell. The PEWE cell operated at a cell temperature of 100°C shows a 5 times increased cell voltage loss rate compared to the PEWE cell at 60°C. The initial performance gain was found to be consumed after a projected operation time of 3,500 h. Elevated temperature operation is only viable if a voltage loss rate of less than 5.8 μV h −1 can be attained. The major degradation phenomena that impact performance loss at 100°C are ohmic (49%) and anode kinetic losses (45%). Damage to components was identified by post-test electron-microscopic analysis of the catalyst coated membrane and measurement of cation content in the drag water. The chemical decomposition of the ionomer increases by a factor of 10 at 100°C vs 60°C. Failure by short circuit formation was estimated to be a failure mode after a projected lifetime 3,700 h. At elevated temperature and differential pressure operation hydrogen gas cross-over is limiting since a content of 4% hydrogen in oxygen represents the lower explosion limit.

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Section: T [°C]mentioning

confidence: 99%

Understanding Degradation Effects of Elevated Temperature Operating Conditions in Polymer Electrolyte Water Electrolyzers

Garbe

Futter

Agarwal

et al. 2021

J. Electrochem. Soc.

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show abstract

“…However, its utilization in an electrochemical device that has such an aggressive environment, full of water, with high oxygen content and traces of fluoride ions, low pH, and temperatures of 80 °C or above, is unthinkable. It has been shown that 5 ppm Cu 2+ causes significant performance decay without a subsequent recovery, as Cu 2+ tends to adsorb and remain in the membrane [ 35 ].…”

Section: Introductionmentioning

confidence: 99%

Towards Replacing Titanium with Copper in the Bipolar Plates for Proton Exchange Membrane Water Electrolysis

et al. 2022

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For proton exchange membrane water electrolysis (PEMWE) to become competitive, the cost of stack components, such as bipolar plates (BPP), needs to be reduced. This can be achieved by using coated low-cost materials, such as copper as alternative to titanium. Herein we report on highly corrosion-resistant copper BPP coated with niobium. All investigated samples showed excellent corrosion resistance properties, with corrosion currents lower than 0.1 µA cm−2 in a simulated PEM electrolyzer environment at two different pH values. The physico-chemical properties of the Nb coatings are thoroughly characterized by scanning electron microscopy (SEM), electrochemical impedance spectroscopy (EIS), X-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM). A 30 µm thick Nb coating fully protects the Cu against corrosion due to the formation of a passive oxide layer on its surface, predominantly composed of Nb2O5. The thickness of the passive oxide layer determined by both EIS and XPS is in the range of 10 nm. The results reported here demonstrate the effectiveness of Nb for protecting Cu against corrosion, opening the possibility to use it for the manufacturing of BPP for PEMWE. The latter was confirmed by its successful implementation in a single cell PEMWE based on hydraulic compression technology.

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“…Cationic Contamination. The accumulation of metallic cations like Fe 3+ [96], Cu 2+ and Al 3+ [97], Ca 2+ [98], and Na + [99] in the MEA can range from being a contributing factor to being the dominating mechanism in PEM electrolysis performance degradation. The foreign cationic impurities may originate from impurities in stack component materials, impurities of feed water, and other sources [96,100].…”

Section: Load Cycling and Constant Currentmentioning

confidence: 99%

“…The distribution of dissolved contaminants is promoted by the over stoichiometric feed rate (λ > 4) of liquid water [101] in PEMWE. Cationic contamination from Fe 3+ , Cu 2+ , and Al 3+ has been reported as a result from degradation of materials and corrosion of pipes in the system [96,97]. Li et al [102] investigated the effect of long-term Adapted from [93] with permission from Elsevier.…”

Section: Load Cycling and Constant Currentmentioning

confidence: 99%

“…The researchers observed a significant performance decay in which the degradation rate reached to 128.9 μV h −1 after the 829 h contamination test [102]. In a more recent publication, Li et al [97] investigated the effect of further cationic impurities (Fe 3+ , Cu 2+ , and Al 3+ ions) in single PEMWE cells and found that all impurity ions have a severe impact on the cell performance. Cell poisoning and associated performance breakdown can already occur at low concentrations of 3 ppm Al 3+ on the cathode side [97].…”

Section: Load Cycling and Constant Currentmentioning

confidence: 99%

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A Review of Accelerated Stress Tests for Enhancing MEA Durability in PEM Water Electrolysis Cells

Kuhnert

Hacker

Bodner

2023

International Journal of Energy Research

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During the past decades, a significant amount of excellent scientific results has been generated in the field of polymer electrolyte membrane water electrolysis (PEMWE). Compared to current state-of-the-art technologies, PEMWE offers the opportunity to produce green hydrogen with zero carbon emissions. However, the membrane electrode assembly (MEA), whose price is still high for a rather limited lifetime, needs further improvement in terms of performance, cost, and durability. In order to efficiently process novel materials, accelerated stress tests (ASTs) can be implemented to provoke and investigate cell ageing processes and assess failure modes under real-life conditions. In this review, the different accelerated stressors of the main components of the MEA are discussed, and recent publications of ASTs in the study of PEMWE cell durability are summarized. Furthermore, a concise review of the degradation mechanisms for the individual MEA components depicted in recent publications is presented. The different aspects identified in this review serve as a roadmap to further advance the durability of novel stack materials.

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The effects of cationic impurities on the performance of proton exchange membrane water electrolyzer

Cited by 31 publications

References 43 publications

Understanding Degradation Effects of Elevated Temperature Operating Conditions in Polymer Electrolyte Water Electrolyzers

Understanding Degradation Effects of Elevated Temperature Operating Conditions in Polymer Electrolyte Water Electrolyzers

Towards Replacing Titanium with Copper in the Bipolar Plates for Proton Exchange Membrane Water Electrolysis

A Review of Accelerated Stress Tests for Enhancing MEA Durability in PEM Water Electrolysis Cells

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