@article {1069,
	title = {Performance enhancement of PEM electrolyzers through iridium-coated titanium porous transport layers},
	journal = {Electrochemistry Communications},
	volume = {97},
	year = {2018},
	month = {12/2018},
	pages = {96-99},
	abstract = {<p><span style="color: $\#$111111; font-family: -apple-system, system-ui, {\textquoteright}Segoe UI{\textquoteright}, {\textquoteright}Helvetica Neue{\textquoteright}, Helvetica, Arial, sans-serif; font-size: 13px; white-space: pre-wrap; background-color: $\#$fafafa;">Published on December 1st, 2018. Titanium-based porous transport layers (PTL) used in polymer electrolyte membrane (PEM) water electrolyzers suffer from surface passivation (titanium oxidation), which increases the interface resistance between the PTL and electrode. For long-term operation, PTLs are typically coated with considerable amounts of platinum or gold to ensure reasonable performance profiles over time. Moreover, it is well known that the oxide forms of platinum and gold are not stable under electrolysis conditions. In this study, an easy and scalable method is introduced to protect the titanium PTL from passivation by sputtering very thin layers of iridium onto commercially-available titanium PTLs. The iridium layer reduces the overall ohmic resistance of the PTL/catalyst layer interface and improves the cell{\textquoteright}s performance to that achieved with carbon-based PTLs. The coating process homogeneously deposited iridium throughout the inner structure of the PTL. The findings of this study may lead to the use of iridium as a protective layer for titanium PTLs, potentially enable operation at increased cell voltages and lead to increased electrolyzer durability.</span></p>},
	issn = {1388-2481},
	doi = {10.1016/j.elecom.2018.10.021},
	url = {http://www.sciencedirect.com/science/article/pii/S1388248118302741},
	author = {Chang Liu and Marcelo Carmo and Guido Bender and Andreas Everwand and Thomas Lickert and James L. Young and Tom Smolinka and Detlef Stolten and Werner Lehnert}
}
@article {991,
	title = {Acidic or Alkaline? Towards a New Perspective on the Efficiency of Water Electrolysis},
	journal = {Journal of The Electrochemical Society},
	volume = {163},
	year = {2016},
	note = {{\textquoteright}doi: 10.1021/acsenergylett.0c01132\n - I.Am.Hydrogen{\textquoteright}
{\textquoteright}\n - jyoungstrom{\textquoteright}
{\textquoteright}Jason thinks this is great.\n~\n - jyoungstrom{\textquoteright}
{\textquoteright}\n - estechel{\textquoteright}
},
	pages = {F3197-F3208},
	abstract = {Published on January 1st, 2016.
Water electrolysis is a promising technology for enabling the storage of surplus electricity produced by intermittent renewable power sources in the form of hydrogen. At the core of this technology is the electrolyte, and whether this is acidic or alkaline affects the reaction mechanisms, gas purities and is of significant importance for the stability and activity of the electrocatalysts. This article presents a simple but precise physical model to describe the voltage-current characteristic, heat balance, gas crossover and cell efficiency of water electrolyzers. State-of-the-art water electrolysis cells with acidic and alkaline electrolyte are experimentally characterized in order to parameterize the model. A rigorous comparison shows that alkaline water electrolyzers with Ni-based catalysts but thinner separators than those typically used is expected be more efficient than acidic water electrolysis with Ir and Pt based catalysts. This performance difference was attributed mainly to a similar conductivity but approximately 38-fold higher diffusivities of hydrogen and oxygen in the acidic polymer electrolyte membrane (Nafion) than those in the alkaline separator (Zirfon filled with a 30 wt} KOH solution). With reference to the detailed analysis of the cell characteristics, perspectives for the improvement of the efficiency of water electrolyzers are discussed.},
	issn = {0013-4651, 1945-7111},
	doi = {10.1149/2.0271611jes},
	url = {http://jes.ecsdl.org/content/163/11/F3197},
	author = {Maximilian Schalenbach and Geert Tjarks and Marcelo Carmo and Wiebke Lueke and Martin Mueller and Detlef Stolten}
}
@article {1011,
	title = {An analysis of degradation phenomena in polymer electrolyte membrane water electrolysis},
	journal = {Journal of Power Sources},
	volume = {326},
	year = {2016},
	note = {{\textquoteright}doi: 10.1021/acsenergylett.0c01132\n - I.Am.Hydrogen{\textquoteright}
{\textquoteright}\n - jyoungstrom{\textquoteright}
{\textquoteright}Jason thinks this is great.\n~\n - jyoungstrom{\textquoteright}
{\textquoteright}\n - estechel{\textquoteright}
},
	pages = {120-128},
	abstract = {Published on September 15th, 2016.
The durability of a polymer electrolyte membrane (PEM) water electrolysis single cell, assembled with regular porous transport layers (PTLs) is investigated for just over 1000~h. We observe a significant degradation rate of 194~μV~h-1 and conclude that 78\% of the detectable degradation can be explained by an increase in ohmic resistance, arising from the anodic Ti-PTL. Analysis of the polarization curves also indicates a decrease in the anodic exchange current density, j0, that results from the over-time contamination of the anode with Ti species. Furthermore, the average Pt-cathode particle size increases during the test, but we do not believe this phenomenon makes a significant contribution to increased cell voltages. To validate the anode Ti-PTL as a crucial source of increasing resistance, a second cell is assembled using Pt-coated Ti-PTLs. This yields a substantially reduced degradation rate of only 12~μV~h-1, indicating that a non-corroding anode PTL is vital for PEM electrolyzers. It is our hope that forthcoming tailored PTLs will not only contribute to fast progress on cost-efficient stacks, but also to its long-term application of PEM electrolyzers involved in industrial processes.},
	issn = {0378-7753},
	doi = {10.1016/j.jpowsour.2016.06.082},
	url = {http://www.sciencedirect.com/science/article/pii/S0378775316307844},
	author = {Christoph Rakousky and Uwe Reimer and Klaus Wippermann and Marcelo Carmo and Wiebke Lueke and Detlef Stolten}
}
@article {1012,
	title = {Validation and characterization of suitable materials for bipolar plates in PEM water electrolysis},
	journal = {International Journal of Hydrogen Energy},
	volume = {40},
	note = {{\textquoteright}doi: 10.1021/acsenergylett.0c01132\n - I.Am.Hydrogen{\textquoteright}
{\textquoteright}\n - jyoungstrom{\textquoteright}
{\textquoteright}Jason thinks this is great.\n~\n - jyoungstrom{\textquoteright}
{\textquoteright}\n - estechel{\textquoteright}
},
	pages = {11385-11391},
	abstract = {The polymer electrolyte membrane (PEM) electrolysis cell is a promising prospect for the production of clean hydrogen by energy of renewable wind and solar sources. One component of the PEM electrolyzer is the bipolar plate (BPP), which serves as a multi-function component during PEM water electrolysis. Titanium is typically regarded as the state-of-the-art material. Mechanically it could potentially be replace by lower-cost materials such as stainless steel, but under the harsh environmental conditions present in PEM water electrolysis, stainless steel is not corrosion-resistant and metal ions can dissolve. In this case metal ions would poison the catalyst and membrane, which leads to a reduction in the cell performance [1]. We have tested several coatings such as Au and TiN in PEM water electrolysis environments of varying severity for the application as a protective layer of bipolar plates. In order to determine possible candidates for a long-term test under real simulated PEM water electrolysis conditions, an experiment to determine pH value in PEM water electrolysis operation was developed to obtain the required pH value for the ex-situ testing of various coating materials.},
	issn = {0360-3199},
	doi = {10.1016/j.ijhydene.2015.04.155},
	url = {http://www.sciencedirect.com/science/article/pii/S0360319915010939},
	author = {Manuel Langemann and David L. Fritz and Martin M{\"u}ller and Detlef Stolten}
}
