bluuebunny/crossref_metadata_2025_split huggingface dataset:
Stochastic Generation of Electrolyzer Catalyst Layers
Authors: Seip Tess , Lee Keonhag Keonhag , Shaigan Nima , Dinu Marius , Fatih Khalid , Bazylak Aimy 
Published: November 2022

Developing clean energy technologies, such as polymer electrolyte membrane electrolysis (PEMWE), is essential to mitigate the negative impacts of climate change. However, one persistent barrier to PEMWE uptake is high catalyst costs, which can account for up to 47% of total stack costs [1]. This makes the catalyst a key target for cost savings via material optimization, as the mechanisms linking structure, mass transport, and charge transport remain relatively ambiguous in the literature [2], [3]. Previous studies have explored stochastic material generation and pore network modelling in the porous transport layer (PTL), but such analysis has yet to be performed for the bulk catalyst layer [4].
In this study, we introduced a method for replicating the complex pore structure observed in commercially available catalyst materials using stochastic generation techniques. This method creates catalyst structures by using a desired pore size distribution (PSD) as an input, identifying and generating the macro- and microporous regions of the PSD, and then combining the two regions using a custom divider. Statistical analysis (two sample t-test and two sample K-S test) was used to determine the similarity of generated structures to previously imaged commercial catalyst materials. Moreover, pore network modelling techniques were applied to the generated structures to evaluate electrical and mass transport properties. Through these methods, we show that both transport properties and PSD characteristics of generated materials were within experimentally measured ranges, and altering elements of the PSD can result in order of magnitude changes in electrical conductivity, proton conductivity, and through plane permeability.
The methodology presented in this work can be used to evaluate transport properties of various catalyst and catalyst-layer designs with novel pore size distributions. The local transport properties obtained can provide estimates for catalyst properties seldom reported in the literature, facilitating the design and informing the fabrication of next generation, ultra low loading catalyst materials.
[1] A. Mayyas, M. Ruth, et al., Manufacturing Cost Analysis for Proton Exchange Membrane Water Electrolyzers, United States (2019).
[2] Z. Taie, X. Peng, et al., ACS Appl. Mater. Interfaces, 12, 47, 52701–52712 (2020).
[3] J. Lopata, Z. Kang, et al., J. Electrochem. Soc., 167. 064507 (2020).
[4] J. K. Lee, C. H. Lee, and A. Bazylak, J. Power Sources, 437, 226910 (2019).
The Impacts of Membrane Pinholes on Performance and Hydrogen Crossover in PEM Water Electrolysis
Authors: Liu Chang , Wrubel Jacob A , Padgett Elliot , Bender Guido 
Published: November 2022

Polymer electrolyte membrane (PEM) water electrolysis is a promising energy storage technology to produce highly pure hydrogen with high efficiency 1. However, to implement it on a larger scale, it is essential to understand the effects of defects and the required tolerances and quality controls during manufacturing or subsequent handling. Inhomogeneities in membrane electrode assembly (MEA) component materials caused by the manufacturing process or subsequent handling can lead to performance loss and failure 2. Defects such as membrane pinholes, cuts, tears, abrasions, or perforations can all potentially impact MEA performance. In terms of impact, a loss of integrity of the membrane can allow bulk gas transport (crossover) and/or electrical shorting 3.
In particular, hydrogen crossover is a crucial issue for PEM water electrolysis in terms of safe operation and efficiency losses, especially at increased hydrogen pressures. Crossover reduces the overall efficiency of the system and poses flammability hazards under certain conditions 4. Pinholes that form during the manufacturing process or during operation through degradation of the membrane lead to dramatically increased hydrogen crossover.
In this study, the impacts of membrane pinholes on the performance and hydrogen crossover of PEM water electrolyzer cells are studied. Pinholes with different sizes are artificially introduced to the MEA to investigate the effects on the initial cell performance and hydrogen crossover rate under various backpressure and current density conditions.

Reference

Liu, C.; Shviro, M.; Gago, A. S.; Zaccarine, S. F.; Bender, G.; Gazdzicki, P.; Morawietz, T.; Biswas, I.; Rasinski, M.; Everwand, A., Exploring the Interface of Skin‐Layered Titanium Fibers for Electrochemical Water Splitting. Adv Energy Mater
2021,
11 (8), 2002926.

Ulsh, M.; DeBari, A.; Berliner, J. M.; Zenyuk, I. V.; Rupnowski, P.; Matvichuk, L.; Weber, A. Z.; Bender, G., The development of a through-plane reactive excitation technique for detection of pinholes in membrane-containing MEA sub-assemblies. Int J Hydrogen Energ
2019,
44 (16), 8533-8547.

Phillips, A.; Ulsh, M.; Mackay, J.; Harris, T.; Shrivastava, N.; Chatterjee, A.; Porter, J.; Bender, G. J. F. C., The effect of membrane casting irregularities on initial fuel cell performance. 2020,
20 (1), 60-69.

Martin, A.; Trinke, P.; Stähler, M.; Stähler, A.; Scheepers, F.; Bensmann, B.; Carmo, M.; Lehnert, W.; Hanke-Rauschenbach, R. J. J. o. T. E. S., The Effect of Cell Compression and Cathode Pressure on Hydrogen Crossover in PEM Water Electrolysis. 2022,
169 (1), 014502.
Para-polybenzimidazole Membranes for HCl Electrolysis at High (T < 160 oC) Temperatures
Authors: Likit-anurak Kris , Mukhin Nikolai Yurii , Brannon Jamie Katherine , Hepstall Aubrey Madelleine , Murdock Laura , Benicewicz Brian , Shimpalee Sirivatch , Meekins Benjamin 
Published: November 2022

Chlorine (Cl2) is a fundamental feedstock material for the chemical industry, and chlorine-derived products contribute more than $46 billion to the US economy annually. Chlorine plays a major role in many applications such as clean drinking water, pharmaceuticals, and crop protection chemicals. Most chlorine is produced from electrolysis of brine1. Chlorine can also be produced from hydrochloric acid by electrolysis. There are two primary techniques to recycle HCl to Cl2 via electrolysis--a diaphragm cell, which has the advantage of generating H2 as the product, and Proton Exchange Membrane (PEM) electrolyzer, which has the benefit of a higher conversion rate and lower energy consumption2,3. PEM electrolyzers are limited by the Nafion membrane separator, which requires hydration to conduct protons efficiently and is limited to temperatures of ≤ 120 °C. para-Polybenzimidazole (PBI; brand name Celtec-P) membranes are known as high temperature (T ≤ 230 °C) polymer separators that do not require hydration to maintain efficient proton conductivity and can operate in strong acid conditions4–6.
In this work, we demonstrate a completely anhydrous HCl electrolysis system using a Celtec-P membrane that operates at temperatures up to 160 °C and has apparent conversion efficiencies up to 93% at 1.8V. We also discuss the results of an experimentally validated computational fluid dynamics (CFD) model and how this model can be used to elucidate and overcome potential electrolyzer limitations.

Reference

Pamphlet 1 Chlorine Basic, 8th ed., p. 62, The Chlorine Institute, (2014).

Industrial Solutions HCl Electrolysis Chlorine Recovery for Greater Sustainability. Thyssenkrupp AG. Accessed December 20, 2021. https://ucpcdn.thyssenkrupp.com/_legacy/UCPthyssenkruppBAISUhdeChlorineEngineers/assets.files/products/hydrochloric_acid_recycling/thyssenkrupp_hcl_electrolysis_brochure_web_1.pdf.

“Industrial Technologies Program: Advance Chlor-Alkali Technology.” Office of Energy Efficiency and Renewable Energy,U.S. Department of Energy, January 2006. https://www1.eere.energy.gov/manufacturing/industries_technologies/imf/pdfs/1797_advanced_chlor-alkali.pdf.

T. R. Garrick et al., J. Electrochem. Soc., 164, F1591–F1595 (2017).

L. Xiao et al., Chem. Mater., 17, 5328–5333 (2005).

J. A. Mader and B. C. Benicewicz, Macromolecules, 43, 6706–6715 (2010).
Internal Mass Transport Induced Voltage Losses during Water Electrolysis on Interconnected Nickel Nanowire Mesh Electrodes
Authors: Blom Martijn J.W. , Steegstra Patrick , Vereecken Philippe M. 
Published: November 2022

Nickel nanowire mesh electrodes offer great potential for water electrolysis in alkaline environment, given their high internal surface area, mechanical strength, and alkaline resistance. Here we use a nickel nanowire mesh with a specific area of 26 m2/cm3, resulting in ~100-fold area enhancement for a 4µm thick nanowire mesh, compared to planar nickel. This highly benefits geometric current density, potentially into a regime where mass transport is the main limiting factor. Therefore, we performed a systematic study of electrode behaviour under various mass transport conditions to decouple kinetic and mass transfer related contributions to electrode voltage losses.
An electrochemical flow cell was designed to measure the nanowire mesh electrode performance under optimal mass transport conditions. The cell provided electrolyte flow through the nanomesh, enabling convective supply of reagent into the nanopores as well as convective removal of reaction products. Facilitated by the inherent strength of the nanowire mesh, superficial flow velocities up to 1 cm/s could be obtained, with which geometric current densities as high as 320 mA/cm2 could be measured in the kinetically limited (flowrate independent) regime.
Internal mass transport limitations were isolated by use of an inverted rotating disk electrode (iRDE). Koutecky-Levich analysis was performed to compensate for external mass transfer contributions on both nanowire mesh electrodes and planar electrodes. The nanowire mesh as iRDE resembles operating conditions in an electrolyzer, whereas the planar electrode provides a well-defined benchmark area for the electrode surface activity.
For both the oxygen evolution reaction as the hydrogen evolution reaction, mass transport limitations were studies as function of current density and electrolyte (NaOH) concentration. Nanowire mesh electrode operation in the presence of internal mass transport limitations was compared to the non-limited condition and planar benchmark, from which the electrode effectiveness factor could be calculated. A 1-d simplified model of the electrode was used to explain the observed phenomena and to provide guidance for design optimization.
Electronic Structure Modulation of Sulfur-Retaining Nickel-Based Electrocatalyst to Improve the Oxygen Evolution Reaction
Authors: Han Man Ho , Oh Hyung-Suk 
Published: November 2022

Water electrolysis is considered as a key energy source to produce hydrogen for achieving a clean and sustainable society. Improving the sluggish kinetics of the oxygen evolution reaction (OER) is focused to overcome the limit efficiency of water electrolysis. Transition metals, especially Ni, are one of the most promising materials for the alkaline OER because of good catalytic activities, stabilities and cost efficiency. Ni based materials, such as Ni oxyhydroxides, hydroxides, phosphides and sulfides, are intensively developed for use as OER catalysts. Recently, the sulfurization of transition metals is introduced as an effective method to improve the intrinsic electrocatalytic activities. The role of S has been summarized in 2 ways. S accelerates the regeneration of transition metals in alkaline media that S is dissolved and exchanged with O species. Mullins et al. reported Nickel oxide derived from Ni-S. It exhibits amorphous and large active surface morphology which is favorable OER. The other role is that remaining S modulates the electronic structures of Ni catalysts reducing the energy barrier for the OER. Wu et al. developed ultrathin Fe-doped Ni3S2 for overall water splitting. Based on density functional theory calculations, the Fe-doped Ni3S2 surface exhibits an optimized energy for water adsorption and dissociation, which enhances the intrinsic activity for the OER. However, in-situ/operando experimental studies regarding the effects of residual S are rare.
Herein, we report the role of the remaining S in Ni catalysts that exhibit longer Ni-O bonding in the NiOOH phase produced in-situ. C-supported Fe- and Co-doped nickel sulfide catalysts (NiFeCo-S/C) is prepared using a simple impregnation method with heating under an H2S atmosphere. We tested the electrochemical properties of the NiFeCo-S/C in alkaline media of 1 M KOH. It achieved current density of 10 mA cm-2 with only overpotential of 267.2 mV. Also, it maintained the OER activities for 24 h at current densities of 10 and 50 mA cm-2, respectively. Moreover, the prepared catalyst was analyzed the change of electronic structure and bonding group using in-situ/operando X-ray absorption spectroscopy (XAFS) and surface-enhanced Raman spectroscopy (SERS) under OER condition. Based on these results, we could elucidate the effects of the remaining S during the OER.

Figure 1
3D Metal-Organic Framework Based Layered Double Hydroxide Core Shell Structure for Enhanced Oxygen Evolution Reaction
Authors: Liu Ziqi , Lee Min Hwan , Garcia ThomasJae 
Published: November 2022

Electrochemical water splitting, an effective approach of generating high purity hydrogen in a clean way, is composed of two half reactions: hydrogen evolution reaction (HER) and oxygen evolution reaction (OER).[1] OER is the main rate-limiting half reaction for water splitting due to its sluggish four-electron transfer process.[2]
,
[3] An efficient electrocatalyst is indispensable to minimize the activation barrier for the reaction and achieve a high efficiency.
Recently, two-dimensional (2D) layered double hydroxides (LDHs) have shown promises as one of the most effective electrocatalysts towards OER. However, the confined nanostructure with poor electronic conductivity inhibits their further enhanced catalytic performance towards OER. Herein, a 3D core-shell LDH structure is synthesized through a facile one-step reaction strategy, in which the terephthalic acid and urea is employed as the organic ligand for the metal organic framework (MOF) precursor and surface coordination buffer between LDH and MOF. Benefiting from the hierarchical 3D microstructure with uniformly nanosheets grown on the surface, the as prepared electrocatalyst exhibits rich edge active sites and enormous electrochemical surface area. The representative sample (namely, CoNi-LDH@BDC) achieves an excellent OER activity with a low overpotential of 280 mV at 100 mA cm-2 and robust cyclic stability. In addition, quasi-operando studies using X-ray absorption and X-ray photoelectron spectroscopy further elucidate that the Co-Ni dual metal sites act as the main active site while Ni of high valence state is a favorable site to oxygen for the O-O bond formation. The prominent OER performance is also attributed to the synergistic effect between different transition metal atoms.

References

[1] L. Yu, H. Zhou, J. Sun, F. Qin, F. Yu, J. Bao, Y. Yu, S. Chen, Z. Ren, Energy Environ. Sci.
2017, 10, 1820.
[2] Y. Wang, C. Xie, Z. Zhang, D. Liu, R. Chen, S. Wang, Adv. Funct. Mater.
2018, 28, 1703363.
[3] L. Zhuang, L. Ge, Y. Yang, M. Li, Y. Jia, X. Yao, Z. Zhu, Adv. Mater.
2017, 29, 1606793.
[4] R. Frydendal, E. A. Paoli, B. P. Knudsen, B. Wickman, P. Malacrida, I. E. L. Stephens, I. Chorkendorff, ChemElectroChem
2014, 1, 2075.
[5] Y. Lee, J. Suntivich, K. J. May, E. E. Perry, Y. Shao-Horn, Synthesis and activities of rutile IrO 2 and RuO 2 nanoparticles for oxygen evolution in acid and alkaline solutions, Vol. 3, American Chemical Society, 2012, pp. 399–404.
[6] M. Gao, W. Sheng, Z. Zhuang, Q. Fang, S. Gu, J. Jiang, Y. Yan, J. Am. Chem. Soc.
2014, 136, 7077.
Lithium Metal Polymer Batteries: Towards Operation at Ambient Temperature
Authors: Pinchart Camille , Zanotti Jean-Marc , Berrod Quentin , Judeinstein Patrick , Ramos Raphael , Modesto Nino 
Published: November 2022

A canonical electrolyte for lithium metal polymer batteries is PEO (Polyethylene Oxide) doped with lithium salts1. Its ionic conductivity is closely related to the local dynamics (Å, ps) of the polymer chains acting as a solid solvent. For good conductive performances, these batteries must be maintained above the melting point of the bulk PEO (TM
=60°C).
In order to lower this operating temperature, we propose to use one-dimensional nanoscale confinement to downshift the melting point of the confined electrolyte according to ΔTM ≈ 1/d where d is the pore diameter (Gibbs-Thomson effect)².
Porous polymer composite membranes based on vertically aligned Carbon NanoTubes (VA-CNTs)3
,4 seem to be able to meet this ambitious target. The pores are cylindrical (diameter 4nm, length 100µm) and have the particularity of being all macroscopically oriented and parallel.
The effect we are seeking is driven by the curvature of the confining pore. It is then critical to ensure that only the interior of the CNTs is the permeable part of the membrane. We have followed by neutron imaging the time dependence of the penetration of the electrolyte within the membrane. We evidence a critical feature we target: only the interior of the CNTs are the permeable moieties of the membrane.
As for the PEO dynamics under confinement, the electrolyte’s multiscale transport properties and ionic conductivity are characterized by PFG-NMR at the micrometer scale and Electrochemical Impedance Spectroscopy (EIS) at the macroscopic scale. We report a conductivity gain of one order of magnitude under VA-CNT confinement.
Nevertheless, on a multitude of non-connected CNT pores, conductivity fluctuations are not in phase: by such classical spectroscopic techniques, only an averaged conductivity is measured. To complement the spectroscopic approach, we also probe the system by the Voltage Clamp (also called Single Pore) technique. The analysis of the conductivity noise going through a single CNT pore can indeed reveal whether the conductivity under confinement5 is due to an anomalous mobility and/or charge fluctuations.
(1) Xue, Z. et al., Poly(Ethylene Oxide)-Based Electrolytes for Lithium-Ion Batteries. J. Mater. Chem. A
2015, 3 (38), 19218–19253.
(2) Alba-Simionesco, C. et al., M. Effects of Confinement on Freezing and Melting. J. Phys.: Condens. Matter
2006, 18 (6), R15–R68.
(3) Berrod, Q. et al., Enhanced Ionic Liquid Mobility Induced by Confinement in 1D CNT Membranes. Nanoscale
2016, 8 (15), 7845–7848.
(4) Zanotti, J.-M. et al., Nanocomposite membranes for electrochemical devices. Patent WO2016151142 A1.(2016)
(5) Tasserit, C. et al., Pink Noise of Ionic Conductance through Single Artificial Nanopores Revisited. Phys. Rev. Lett.
2010, 105 (26), 260602.

Figure 1
Effect of Carbon Nanotubes on the Electrochemical Performance of Li Powder Composite Anodes
Authors: Dzakpasu Cyril Bubu , Ryou Myung-Hyun , Lee Yong Min 
Published: November 2022

To achieve the high energy density of lithium secondary batteries, the Li metal anode with a high theoretical capacity (3860 mAh g-1) and the lowest electrochemical potential (-3.04 vs. SHE) has attracted attention. However, Li metal is plagued with challenges such as irregular dendritic growth during cycling and low Coulombic efficiency (CE), which hinder its commercialization as an anode. Li metal powder (LMP) offers a solution to these problems by enlarging the surface area resulting in a lower effective current density. However, the commercial LMP passivated by Li2CO3 layer on the surface could hinder the electrical contact between individual LMPs as well as LMP and Cu current collector. Consequently, a series of LMP particle contact failures result in dead regions within the LMP electrode where the Li source cannot be fully activated.
Herein, we report the effect of multiwalled CNTs on the electrochemical performance of Li metal powder-based anodes for Li metal batteries. The CNT-LMP anode exhibits a remarkable improvement in the electrochemical performance of coin cells compared to the bare LMP system. This improvement is attributed to the enhanced electrical connection between individual LMP particles, activation of full Li utilization, and the seeding effect of CNTs. Electrochemical properties were investigated using postmortem scanning electron microscopy and galvanostatic cycling techniques.
Multi-Functional AgNO3 Preplanted in Li Metal Powder Electrodes
Authors: Kang Dongyoon , Jin Dahee , Dzakpasu Cyril Bubu , Han Jiwon , Ryou Myung-Hyun , Lee Yong Min 
Published: November 2022

Li metal powder (LMP) is very promising in practically fabricating thin Li electrodes for high-energy-density Li metal batteries (LMBs), because it allows not only conventional slurry coating but also co-use of functional additives. Also, the LMP has several times higher surface area than that of the Li foil with tens of micrometers, which reduces the local current density and suppresses Li dendritic growth. However, the uneven and resistive protection layer on the LMP surface could lead to the non-uniform composition in solid electrolyte interphase (SEI), thereby resulting in the localized Li nucleation and growth. Thus, the introduction of stabilizing additives for LMP is one of the most promising solutions to control the Li stripping/plating behavior.
Herein, we report a AgNO3-preplanted LMP electrode having stable long-term cycle performance. The AgNO3 in the slurry mixing and coating process can chemically form lithiophilic Ag particles on the LMP surface, which act as nucleation sites. In addition, since the metallic Ag particle is embedded within the LMP electrodes, it continuously contributes as the seeding points even under extreme volume expansion during cycling. Additionally, nitrates can help form Li3N-rich SEI with higher ionic conductivity and Young’s modulus. Finally, AgNO3-preplanted LMP electrode of 40 μm survives up to 500 cycles with 86.8% capacity retention at 1C/3C charging/discharging condition. Therefore, this superior cycle performance enables AgNO3-preplanted LMP electrodes to be an attractive anode candidate for LMBs.