bluuebunny/crossref_metadata_2025_split huggingface dataset:
Engineering and Testing of CCM Modifications for Improved Operational Flexibility, Durability and Performance of Fuel Cells and Electrolyzers
Authors: Wilkinson David P. , Bonakdarpour Arman , Kwan Jason T.H. , Daniel Lius 
Published: July 2022

The performance, durability and cost of PEM fuel cell and electrolyzer systems still requires further improvements before they can be widely adopted. Along with improved electrocatalysts, low cost interface modifications and intermediate layers are important to improve the operation of catalyst coated membranes (CCMs) and meet commercial requirements. In this presentation we present some examples of the modification of conventional commercial CCM and MEA modifications with performance benefits. This would include for example the effect of improving the microporous layer (MPL) / catalyst layer (CL) interface by reducing the gaps to improve power density1, the improvement of cross-over and operational flexibility with a thin electrolessly deposited catalyst layer at the membrane surface 2, and modification of the porous transport layer (PTL) / catalyst interface3.
A new testing method for the evaluation of commercial CCMs was used in this work which can accelerate design and testing of these new and modified CCMs. This new method uses a Modified Rotating Disk Electrode (MRDE)4 which allows electrodes and CCMs to be tested up to high current densities, e.g., 2 A/cm2, and eliminates the variability and issues associated with thin film RDE testing. Figure 1 shows an example of testing the oxygen evolution reaction (OER) performance for different PTLs with a commercial CCM using the MRDE. The MRDE testing is also useful for carrying out accelerated degradation (ADT) testing of CCMs for fuel cell or electrolyzer applications5 and has the potential to be used as a quality control tool for CCM manufacturing lines.

References:

L. Daniel, A. Bonakdarpour and D.P. Wilkinson, Fuel Cells, 20(2), F1-F7 (2020)

L.Daniel, A. Bonakdarpour and D.P. Wilkinson, ACS Applied Nano Materials, 2, 3127-3137 (2019); J. of Power Sources, 471, 228418 (2020)

M. Kroschel, A. Bonakdarpour, J.T.H. Kwan, P. Strasser and D.P. Wilkinson, Electrochim.
Acta, 317, 722-736 (2019)

J. T. H. Kwan, A. Bonakdarpour, G. Afonso, and D. P. Wilkinson, Electrochim. Acta, 258, 208–219 (2017).

P.J. Petzold, J.T.H. Kwan, A. Bonakdarpour, and D.P. Wilkinson, J. Electrochem. Soc., 168(2), 026507 (2021)

Figure 1: The effect of different titanium current collector meshes on OER performance using a commercial IrO2-based CCM obtained by the MRDE tool. Inset shows the pictures of different Ti meshes examined.

Figure 1
Understanding Key Factors during Dod Inkjet Printing Towards Precise Fabrication of Micro Energy Systems
Authors: Huang Hong , Hill Theresa 
Published: July 2022

There is an ever-increasing need for micro energy systems that can power miniature, unmanned, or remotely-located devices. Drop-on-Demand (DOD) inkjet fabrication is uniquely positioned for this demand due to its low-cost processing with microscale resolution, high throughput, reproducibility, and ease in shape design. This study seeks to capitalize on the advantages of DOD inkjet printing for application to manufacturing micro energy conversion/storage systems, by defining the fundamental jet kinematics and key factors underpinning the inkjet printing process.
The ink used in this study was a dilute colloidal ink suspension composed of a common solid oxide fuel cell (SOFC) cathode material [La0.6Sr0.4Fe0.8Co0.2O3 (LSFC)] and organic solvent α-terpineol. The results were evaluated systematically in terms os final deposition quality, resolution, and microstructure. Favorable fluid kinematics were identified that attained uniform, well-shaped, circular 0-D dots about 0.1 µm thick and 60 µm in diameter. To increases the microfeature thickness and x/y plane dimensions , multiple and/or sequential ink passes were employed. For printing 1-D lines, the spacing between droplets was imperative to fabricating quality micro features. Using appropriate conditions, 1-D lines with x/y dimensions < 100 µm and controllable z axis dimensions at 0.1 µm per printing pass with dense, open or networked microstructures were demonstrated. 2-D planes at the dimensions as small as 100 µm by 100 µm were also achieved with smooth surface and continuous intra-planar ceramic coverage. In the course of post-processing the inkjetted cathodes, it was observed that the submicron cathode films printed at optimal conditions, after being sintered at controlled conditions, were uniform, smooth and free of cracks or delamination.
This research demonstrated through fundamental understanding and control of the inkjet fabrication process, cathode features can be printed with controlled dimension and quality towards producing a functioning micro SOFC operable at low temperatures. The knowledge gained from this research will be appliable to other micro energy conversion and storage systems.
Spatially Resolved Deconvolution of Loss Processes in PEM Fuel Cells
Authors: Oppek Philipp , Geörg Mischa , Goosmann Tobias , Reshetenko Tatyana V. , Weber Andre , Krewer Ulrike 
Published: July 2022

The complex operating behaviour of PEM Fuel Cells is heavily influenced by different non-linear loss processes, which limit the cell performance. Depending on the operating conditions, the different losses change in magnitude and characteristic time constants [1]. During technical operation of large-sized PEM Fuel Cells, gradients in operating conditions occur along the gas channels, resulting in an inhomogeneous current density distribution. This is caused by the locally varying electrochemical activity due to in-plane gradients in concentrations of reactants and reaction products, gas pressure and temperature. Consequently, each loss process occurs locally distributed to a varying degree. Therefore, a profound knowledge about the spatial distribution of losses is essential for optimizing the operating strategy as well as the cell and stack components.
The commonly measured I/V characteristics provide only integral information about the overall performance. Thus, the data obtained represent merely the sum of all loss processes averaged over the entire cell area and do not allow detailed conclusions about the respective spatial distribution along the channel.
Inevitably, in order to deconvolute the loss processes in the entire area of large sized cells, an approach is required that provides deeper insight in the processes and their interdependencies. For this purpose, an impedance-based methodology is developed that enables a spatially resolved deconvolution of loss processes. It is based on electrochemical impedance spectroscopy (EIS) and an impedance data analysis by the distribution of relaxation times (DRT) [2,3] that is applied to a segmented cell [4] with almost gradient-free segments. By systematically varying operating conditions the different loss processes are identified, quantified and separated with respect to their characteristic frequencies.
In this contribution the design of the test bench and the segmented cell will be presented. Furthermore, first results regarding the electrochemical characterization and the impedance-based deconvolution of loss processes in a segmented cell will be discussed.

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T. Reshetenko et al., J. Electrochem. Soc. 163, pp. F1100-F1106 (2016)
Oxygen Reduction Reaction Catalyzed By Silicon and Nitrogen Co-Doped Carbon
Authors: Kruusenberg Ivar , Kaare Kätlin , Palgrave Robert , Tsujimoto Masahiko , Kuzmin Anton , Shainyan Bagrat 
Published: July 2022

Finding an alternative catalysts for the oxygen reduction reaction (ORR) has been a key issue in modern
electrocatalysis. Traditional platinum-based catalysts are not viable in the long term and thus much effort
has been focused on non-precious metal catalysts. Heteroatom doped and metal-heteroatom co-doped
carbon materials have emerged as the main candidate for replacing the platinum-based catalysts.
Different MN4 macrocycles, such as metal phthalocyanines and porphyrins, have been studied as
promising materials to prepare electrocatalysts for ORR in alkaline media [1]. While the development of
non-precious metal and non-metal carbon catalysts has gained a lot of attention recently, non-metal
phthalocyanines are a less studied topic [2].
In this work a novel catalyst material including multi-walled carbon nanotubes (MWCNT) and silicon
phthalocyanine dichloride (SiPcCl2) was synthesized and the electrochemical activity towards the oxygen
reduction reaction (ORR) in alkaline media was studied. Different ratios of phthalocyanine-to-nanotubes
were pyrolyzed at 800 °C. After optimizing the ratio of phthalocyanine-to-nanotubes, the pyrolysis process
was also carried out at different temperatures, but the results showed that the best temperature for
pyrolysis is still 800 °C. ORR activity on SiPc/MWCNT catalyst was studied in 0.1 M KOH by employing
rotating disc electrode method. Physical characterization was carried out with X-ray photoelectron
spectroscopy and transmission electron microscopy. The results showed successful incorporation of
silicon and nitrogen into the carbon framework. We show that doping MWCNTs with a non-metal
phthalocyanine creates a highly active ORR catalyst rivaling the activity of metal-based catalysts in
alkaline conditions. This work clearly demonstrates that non-metal macrocyclic compound modified
carbons, similar to the the SiPc/MWCNT can be used as alternative cathode catalysts for the metal-air
batteries and alkaline membrane fuel cells.
[1] Y. Liu, X. Yue, K. Li, J. Qiao, D.P. Wilkinson, J. Zhang, PEM fuel cell electrocatalysts based on
transition metal macrocyclic compounds, Coord Chem Rev. 315 (2016) 153-177.
[2] K.-K. Türk, K. Kaare, I. Kruusenberg, M. Merisalu, U. Joost, L. Matisen, V. Sammelselg, J.H. Zagal, K.
Tammeveski, Oxygen electroreduction on zinc and dilithium phthalocyanine modified multiwalled carbon
nanotubes in alkaline media, J. Electrochem. Soc. 164 (2017) H338-H344.
Synthesis of Platinum-Rare Earth Metal Alloy Catalysts for Proton Exchange Membrane Fuel Cells
Authors: Zhou Quan , Hu Yang , Brandes Benedikt Axel , Cleemann Lars , Jensen Jens Oluf , Li Qingfeng 
Published: July 2022

Electrocatalysts for low temperature fuel cells are based on noble metals and can be promoted by development of alloys of platinum with e.g. late transition metals such as Ni and Co.[1,2] It has been reported that Pt alloys with rare earth (RE) metals exhibit remarkable activity and high stability towards the oxygen reduction reaction.[3] Due to the very low standard reduction potentials and high oxophilicity of rare earth metals, preparation platinum alloys in form of nanoparticles meets great challenges for chemical routes of co-reduction. A one-step method is recently developed to prepare Pt−RE nanoalloys from a mixture of solid state precursors consisting of metal halides in their hydrate forms, a suitable nitrogen-rich compound and a carbon support.[4,5] The synthesis involves in situ formation of a carbon-nitrogen network, onto which the two metals are atomically dispersed. The coordination with nitrogen sites stabilizes the metals, which, upon thermal decomposition under a mild reducing atmosphere, leads to the formation of Pt-RE nanoalloys. The carbon support is introduced either as carbon blacks or carbon supported platinum powder. The pre-formed, either in or ex situ, platinum nanoparticles, facilitates the reduction of rare earth metals thermodynamically driven by the negative alloying free energy. A series of pure crystal phases such as Pt5RE (e.g. La, Ce, Nd), and Pt3RE (e.g. Y, Gd, Tb) have been synthesized in form of carbon supported nanoparticles with tunable metal loadings and alloy particle sizes. One of the typical catalysts is the Pt5Ce/C in a metal to carbon ratio of 30 wt% and an average alloy particle size of ca. 5.5 nm which exhibits an area specific activity of 3.7 times and a mass activity of 1.9 times higher than those of the Pt/C analogue. Further understanding and improvement of the process are in progress and the updated results will be presented in this talk.
[1]. J. K. Norskov et al., Nature Chemistry 1, 37-46 (2009)
[2]. X. Q. Huang et al., Science 348, 1230-1234 (2015)
[3]. M. Escudero-Escribano et al., Science 352, 73-76 (2016)
[4]. Y. Hu et al., J. Am. Chem. Soc. 142, 953–961 (2020)
[5]. Y. Hu et al., Chem. Mater. 33, 2, 535–546 (2021)
Sacrificial Template-Assisted Mechanochemical Production of Highly Active Bifunctional Fe-N-C Catalysts
Authors: Alimbekova Amina , Kosimov Akmal , Yusibova Gulnara , Aruväli Jaan , Käärik Maike , Leis Jaan , Kongi Nadezda 
Published: July 2022

Bifunctional catalyst materials development for energy storage and conversion technologies is notoriously demanding in terms of electrochemistry (low stability, sluggish kinetics and high total overpotential (∆E)) and logistics (environmental safety, production methodologies and cost).
Noble metal electrocatalysts are proven to be good bifunctional catalysts and as a result are being used as benchmark catalysts. However, the environmental and economic sustainability is severely compromised due to the scarcity of these metals. The alternative option is based on first-row transition metal heteroatom-doped carbon materials. Low cost, high availability, great electrocatalytic activity and stability promise to be a suitable noble metal free catalyst for oxygen evolution reaction (OER) and oxygen reduction reaction (ORR).
This work showcases a high performance Fe-N-C type material with sustainable synthesis and efficient activity towards ORR and OER. Unlike various classical methods for electrocatalyst synthesis, the developed methodology combines mechanochemistry and application of sacrificial template, which yields materials with superior bifunctional oxygen electrocatalytic performance.
(Digital Presentation) ORR/OER Activity and Rechargeable Zinc-Air Battery Performance of B Site Doped Double Perovskite NdBaCoXO5+δ (X= Fe, Ni, Mn)
Authors: Özgür Çağla , Toparli Cigdem 
Published: July 2022

Renewable energy systems and designing economically viable electrochemical energy storage systems is essential to decrease environmental pollution concerns while meeting the growing energy demand. Among the various energy storage devices, rechargeable zinc-air batteries (RZAB) have attracted great attention due to their relatively high specific energy (1218 W.h/kg), and volumetric energy density (6136 W.h/L) cost-effectiveness, and environmental friendliness, comparable to that of lithium–air batteries [1]. However, the sluggish kinetics of the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) during the discharge and recharge process of the air cathode on RZAB prevents large-scale application. So far noble metals (Pt, Ru, Ir) and their alloys (Pt-Ru/C) are used as bifuctional oxygen electrocatalysts in commercial rechargeable RZAB, yet they are too expensive to be viable for large-scale commercial applications. Therefore, designing robust and cost-effective bifunctional oxygen electrocatalysts is prime of importance for RZAB to be commercialized [2]. One of the most promising oxygen bifunctional catalyst are perovskite oxides due to their structural and compositional flexibility [3]. Moreover, the electronic structure of perovskite oxides can be tuned by varying the transition metals at the B site and thus their electrocatalytic performance [4-5].
In this work, first we will demonstrate phase pure fabrication of double perovskite oxide series of NdBaCoXO5+δ (X= Fe, Ni, Mn). Second, OER and ORR performances of the series of NdBaCoXO5+δ (X= Fe, Ni, Mn) will be explained in relation with their electronic structure and work function. Here, we applied NdBaCoMnO6 on a home-made RZAB as air cathode, according to its bifunctional index. Therefore, we will finally present charge-discharge performance of RZAB with NdBaCoMnO6 as air cathode.

J. Fu, Z. P. Cano, M.G. Park, A. Yu, M. Fowler, Z. Chen, Advanced Materials, 29, 1604685 (2016).

Y. Tong, J. Wu, P. Chen, H. Liu, W. Chu, C. Wu, Y. Xie, Journal of the American Chemical Society, 140, 11165-11169 (2018).

W. Yin, B. Weng, J. Ge, Q. Sun, Z. Li, Y. Yan, Energy & Environmental Science, 12, 442-462 (2019).

J. Ahmed, N. Alhokbany, M. Ubaidullah, S. Mutehri, M. M. Khan, S. M. Alshehri, Ceramics International, 46, 20038-20044 (2020).

A. Mulder, N. Benedek, J. Rondinelli and C. Fennie, Advanced Functional Materials, n/a-n/a (2013).
3D Printed Carbon Aerogels for Polymer-Electrolyte Fuel Cells
Authors: Santamaria Anthony D. , Chandrasekaran Swetha , Philbrick Oliver , Worsley Marcus Andre 
Published: July 2022

Carbon aerogels (CA) are known for ultra-low density, very high surface area, fine porous structure, and excellent electrical conductivity. Recent advances in high resolution 3D printing at LLNL enable the manufacturing of complex CA structures which have been demonstrated for electrolysis, flow battery, and supercapacitor applications. Polymer-electrolyte fuel cells (PEFC) may be an excellent candidate for these materials/methods as designers seek to optimize membrane-electrode assemblies to achieve higher power densities. A major challenge to PEFC design is two-phase flow due to water production which causes pore flooding and leads to cell instability. To mitigate these effects, groups have investigated the creation of liquid specific pathways in the porous layers to alleviate liquid buildup and enhance gas diffusion. Methods employed include the addition of small holes to the gas-diffusion layer (GDL) for liquid drainage as well as porosity gradients to exploit capillary effects. While some progress has been made, traditionally manufactured GDLs, which consist of randomly distributed carbon fibers, are limiting. 3D printed CAs are a promising solution as complex macroporous electrode structures can be manufactured out of microporous filaments with a high level of control. Additionally, the process may allow for the consolidation of multiple layers (MPL, GDL, & flow channels) into a single printed architecture. In this work various CA lattice structures were printed using a direct ink write (DIW) method and breakthrough pressures were measured to demonstrate the ability to tune the liquid pathways to achieve specific pressure thresholds. A discussion of the prospects for printed CA electrodes in PEFC will focus on material properties, synthesis techniques, and current challenges.
*anthony.santamaria@wne.edu
(Invited) Bulk Heterojunction Organic Semiconductor Photoelectrodes and Photocatalysts for Solar-Driven Water Splitting
Authors: Sivula Kevin 
Published: July 2022

The bulk heterojunction (BHJ) concept, which has been successfully developed for organic semiconductor-based photovoltaic devices, offers a promising route to high-performance and inexpensive photocatalyst nanoparticles for solar hydrogen production. However, the suitability organic semiconductors (OSs) towards robust and high efficiency photocatalytic water splitting remains an open question. Herein, efforts to understand the stability of OS-based BHJ photoelectrodes for both solar driven water reduction [1] and oxidation [2] are discussed. The integration of a BHJ photoanode and photocathode into a bias-free solar-driven water splitting device is also reported. Finally, the important aspects needed for translating these systems into nanoparticle photocatalysts are examined.

______________

References:

[1]L. Yao, N. Guijarro, F. Boudoire, Y. Liu, A. Rahmanudin, R. A. Wells, A. Sekar, H.-H. Cho, J.-H. Yum, F. Le Formal, K. Sivula, J. Am. Chem. Soc.
2020, 142, 7795.
[2] H.-H. Cho, L. Yao, J.-H. Yum, Y. Liu, F. Boudoire, R. A. Wells, N. Guijarro, A. Sekar, K. Sivula, Nat. Catal.
2021, 4, 431.
Non-Adiabatic Dynamics Simulation of Plasmon-Mediated Chemistry
Authors: Zhang Yu 
Published: July 2022

Localized surface plasmon resonances (LSPRs) have attracted much recent attention for their potential in promoting chemical reactions with light. However, the mechanism of LSPR-induced chemical reactions is still not clear and suffers from many controversies. This presentation will discuss the atomic-scale mechanism of plasmonic hot-carrier mediated chemical reaction exampled by H2 dissociation by employing time-dependent density functional calculations theory and non-adiabatic molecular dynamics. The key observation is that there are nested excited states corresponding to both hot-electron excitation and charge transfer [1]. These nested states cross, facilitating the transitions depicted in the desorption induced by the electronic transitions model and the surface hopping model. I believe this is the first time that such a connection has been made based on a first-principles calculation. Diabatization of these states shows that the charge transfer states are responsible for H2 dissociation, while the hot electron states do not. Previous works only identified the hot electron states, thus were unable to explain the dissociation in a convincing way. Moreover, we also found chemical reaction is tunable if the molecule is placed in the center of the plasmonic dimer [2]. The reaction rate can be either suppressed or enhanced depending on the geometry.
[1] Q. Wu, L. Zhou, G. C. Schatz, Y. Zhang*, H. Guo*, J. Am. Chem. Soc. 2020, 142, 13090–13101.
[2] Y. Zhang*, T. Nelson, S. Tretiak, H. Guo, G. C. Schatz. ACS Nano,
2018, 12, 8415-8422.
Recent Advancements in Morphologies of TiO2 Nanotube Layers and Their Photocatalytic Performance
Authors: Sepúlveda Sepúlveda Lina Marcela , Saldan Ivan , Sopha Hanna , Macak Jan M. 
Published: July 2022

Self-organized TiO2 nanotubes arrays, formed by electrochemical anodization of Ti, have attracted tremendous scientific and technological attention, due to their remarkable properties such as the tunability of dimensions, their directionality, high surface area, low density, and ability to absorb significant amount of incident light [1,2].
The most widely used electrolyte for the synthesis of TiO2 nanotube layers is based on ethylene glycol containing small amounts of water and fluoride ions. However, nanotubes prepared in these electrolytes present a double-walled structure, with the outer wall consisting of almost pure TiO2 and the inner wall consisting of TiO2 contaminated with carbon and fluoride species [3,4]. In the recent years, the selective etching of the inner nanotube wall on Ti layer enabled synthesis of single-wall nanotubes that showed a superior photo-electrochemical performance compared to their double-walled counterparts [5]. An extensive etching enabled also the synthesis of single tube powders, which could be effectively decorated with Fe3O4 nanoparticles to act as magnetically guidable photocatalyst [6,7].
The presentation will focus on the influence of all these nanotube morphologies on the photocatalytic degradation in the liquid phase. In particular, we will discuss, how the annealing temperature of single nanotubes influences their photocatalytic performance [7] and how the wall thickness of the single wall nanotubes can be optimized for the best performance [8]. Experimental details and photocatalytic results will be presented and discussed.
References:
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