bluuebunny/crossref_metadata_2025_split huggingface dataset:
Lithium Dendrite Suppression through Controlled Mass Transfer
Authors: Ryan Emily , Tan Jinwang 
Published: February 2020

Lithium dendrite formation is a critical challenge that limits the lifetime of lithium (Li) metal batteries including lithium oxygen, and lithium sulfur systems. Dendrite growth occurs at the interface between the electrolyte and the Li metal anode. The formation of dendrites affects the local transport properties, the scale of the critical physics of the anode, leads to increased Joule heating and eventual breakage of the dendrites, which can cause short circuits leading to overheating and possible fires. Dendrite formation also decreases the Li available for the electrochemical reactions of the battery, which causes a decrease in cell capacity. In addition to Li metal batteries, dendrite growth is also a problem for other battery chemistries, such as Li-ion, NaS and NiCd. Among previous experimental studies, it has been shown that the dendrites in Li batteries can form one of two structures depending on the operating conditions. Under high current conditions, dendrite formation is typically dense and considered mossy or bush-like in structure; while under low current conditions dendrites form dense needle-like structures. In addition to charging current, many other factors are reported to influence dendrite growth. A close relation between Li ion mass transfer and dendrite growth rate have been shown; while other groups have found a strong influence between convection effects and the morphology of the dendritic structure.
Measuring dendrite growth in situ is challenging, and examining the dendrites post mortem is difficult as they can fall apart during disassembly. To better understand dendrite growth and morphology, computational modeling can be used to investigate the electrode-electrolyte interface and how operating conditions and battery design effect dendrite growth and morphology. In this work, we use a Lagrangian particle based method known as smoothed particle hydrodynamics (SPH) to simulate the reactive transport in the interfacial region to understand Li ion transport effects on dendrite growth. This includes investigation of material properties and battery design, including the use of hybrid electrolytes and separators to restrict Li ion transport. Further studies are conducted to consider how operation and charging rates effect growth.
Results of these computational studies show that restricted Li ion transport can suppress dendrite growth without sacrificing battery performance. This can be accomplished by changing the materials of electrolyte or using hybrid electrolyte designs. Additionally the charging profile can also be used to effectively suppress dendrites.
Neutron Tomographic Investigation of the Effect of Hydrophobicity Gradients within MPL and MEA on the Spatial Distribution and Transport of Liquid Water in Pemfcs
Authors: Kartouzian Dena , Mohseninia Arezou , Markötter Henning , Scholta Joachim , Manke Ingo 
Published: February 2020

Neutron tomography is used to visualize the effect of hydrophobicity variations within the micro porous layer (MPL) and membrane electrode assembly (MEA) of a low-temperature polymer electrolyte fuel cell (PEMFC) on the detailed distribution of water in an operating cell. MEAs and MPLs manufactured in-house with different degrees of wettability are implemented in miniature fuel cells featuring an active area of 8 cm², which are specifically designed for neutron imaging experiments. The tomographies are obtained with a pixel size of 13 µm while maintaining the same operating conditions for all cells for comparability.
The quantitative analysis of the water content in two of these cells next to the lands and the channels of the flow field is shown in Figure 1. It can be clearly observed that the implementation of a hydrophobic MEA significantly changes the overall water distribution within the cell. In contrast to the reference MEA, where more water is found in the catalyst layers compared to the membrane, the hydrophobic MEA has a higher water content inside its membrane.
Implementing a GDL with a more hydrophobic MPL on the cathode side shows a higher water content inside the GDL substrate under the lands compared to the channels. This information can significantly help the optimization of material designs and can also provide valuable data for modeling and simulations of water distributions inside PEMFCs. We will show a detailed analysis of hydrophobicity changes on the water distribution inside the cell components, characterization results of various MPLs and MEAs regarding wettability and porosity analysis as well as performance results at different operating conditions

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Metal Phosphides As Electrocatalyst and Supports for PEM Fuel Cells
Authors: Parra Puerto Andres , Fahy Kieran F. , Goode Angela E , Ryan Mary P , Kucernak Anthony R. J. , NG Kai Ling 
Published: February 2020

One of the main bottle neck for the complete introduction of the fuel cells technology in the market, is their dependency on precious metals as catalyst. Focusing on the electrochemical reactions involved, the most sluggish is the Oxygen Reduction Reaction (ORR). Many techniques and research were done to reach the high optimization for the amount of the precious metal used, keeping the same activity. In the other hand, many investigations were carried on to find non-precious metal catalyst with the same performance for the different reactions (ORR, HER, OER and HOR)[1]. One of those candidates are the metal phosphides [2], however, this catalysts nowadays only are active for ORR, HER, OER and they have very poor activity related to HOR [3]. Here we present the work done related to the really simple synthesis of CoP catalyst with a very interesting ORR catalytic behaviour and peroxide generation under acid and alkaline conditions. Some TEM characterization was done to understand the changes in the morphology before and after the ORR reaction. Another application of these materials is to use thezzm as support, due to their chemical resistance and low cost. As well, depositing platinum on them gives the possibility to obtain an interesting synergistically effect improving the activity with lower loadings of Pt deposited [4].
[1] M. S. Faber and S. Jin, “Earth-abundant inorganic electrocatalysts and their nanostructures for energy conversion applications,” Energy Environ. Sci., vol. 7, no. 11, pp. 3519–3542, Oct. 2014.
[2] A.-M. Alexander et al., “Alternative catalytic materials: carbides, nitrides, phosphides and amorphous boron alloys,” Chem. Soc. Rev., vol. 39, no. 11, p. 4388, Oct. 2010.
[3] R. Prins and M. E. Bussell, “Metal Phosphides: Preparation, Characterization and Catalytic Reactivity,” Catal. Letters, vol. 142, no. 12, pp. 1413–1436, Dec. 2012.
[4] H.-Y. Park et al., “Pd nanocrystals on WC as a synergistic electrocatalyst for hydrogen oxidation reactions.,” Phys. Chem. Chem. Phys., vol. 15, no. 6, pp. 2125–30, 2013.
Bimetallic Nano Electrocatalyst for HER in Alkaline Polymer Electrolysis
Authors: Faid Alaa Y , Manikandan Maidhily , Seland Frode , Barnett Alejandro Oyarce , Sunde Svein 
Published: February 2020

Recent developments in alkaline membrane technology have led to the possibility of using anion-exchange membranes containing alkaline ions in water electrolysis. This technology has the potential of combining the advantage of non-precious catalysts of alkaline process, with the advantages of PEM electrolysis, e.g. fast power-up/power-down rates, low parasitic energy losses and low energy consumption, in other words consolidating the best of both technologies.
Although the HER is a well-studied reaction, it continues to attract the attention of researchers for both practical applications and fundamental understanding. Ni and alloys of Ni (with Fe,Co,Mo) still represent the most suitable electrodes for HER un alkaline media , the differences in the kinetic rates for the HER on various electrode materials in alkaline environments have linked to variations in the hydrogen adsorption energy. Although this supposition is Kinetically viable, it is still puzzling as to why the HER activity on Pt and other catalysts shows a hundred-fold decrease in activity or why the reaction is more sensitive to the catalysts’ surface structure in alkaline media than in acids.
In this study, bimetallic nano particles of NiFe and NiCo were fabricated by oleylamine polyol and co precipitation process , The process of oleylamine involves synthesis of metal-containing compounds in oleylamine. The oleylamine acts as both the solvent and reducing agent. While co precipitation method involves precipitation agent like NaoH to precipitate the metal based nitrates, Different synthesis conditions in terms of concentration, time and heating rate were studied. Structural characterization of produced nanoparticles was carried out using X-ray diffraction, transmission electron microscopy, Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. Electrochemical behavior of nanoparticles investigated using rotating disk electrode. the electrochemical characterization investigated the effect of catalyst composition on electrochemical behavior of the catalyst.

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(Invited) ARPA-E Refuel Program: Electrochemical Synthesis and Utilization of Sustainable Fuels
Authors: Soloveichik Grigorii L. 
Published: February 2020

The Advanced Research Projects Agency (ARPA-E) funds high risk, high reward transformational research to reduce energy related emissions, reduce imports of energy from foreign sources, improve energy efficiency across all economic sectors, and ensure US technological lead in advanced energy technologies, including electrochemical technologies for energy transformation and storage for distributed, grid scale and automotive applications.
Electrochemical technologies have a great potential for increasing efficiency of synthesis of sustainable fuels and their utilization for power generation for different applications. Switching from gaseous fuels (H2, CH4) as an energy vector to liquid fuels has numerous advantages including higher energy density, available infrastructure and increased safety. Low footprint and cost of storage and transportation of carbon-neutral liquid fuels (CNLFs) enables vehicle electrification (directly or as hydrogen carrier), long-time energy storage and effective long-distance energy transportation. Easily liquefied ammonia (4.25 kWh/L) is one of the most promising CNLFs. It can be used directly in fuel cells or as hydrogen carrier for PEM fuel cells thus enabling the infrastructure of hydrogen fueling stations for public transportation. The Renewable Electricity to Fuels through Utilization of Energy-dense Liquids (REFUEL) program funds the development of transformational technologies to reduce the barriers to widespread adoption of intermittent renewable energy sources by enabling the conversion of energy from these sources, water and air to energy-dense CNLFs, mostly ammonia, (Category 1) and their conversion back to electricity using fuel cells (Category 2). The program objective is to demonstrate delivery of source-to-use electricity (including production, transportation, storage, and conversion) at the cost below $0.30/kWh to be competitive with other carbon-free delivery methods.
Development of novel synthetic methods for CNLFs and regenerative fuel cells for energy storage is also being funded via OPEN program. Possible future ARPA-E program targeting the use of CNLFs for transportation (in hybrids, range extenders, APUs) will be also discussed.
(Invited) Electrochemical Ammonia Synthesis - Facts or Dreams?
Authors: Chorkendorff Ib 
Published: February 2020

Producing ammonia from sustainable energy sources is a new and interesting route for decentralized production. Ammonia is an essential chemical for mainly fertilizer production but also an essential compound for the chemical industry. Normally ammonia is produced by large scale production – several thousand tons/day - by the Fritz-Haber process at 150-200 bar and 400 °C. Nature can, however, produce ammonia at ambient conditions using ATP as the energy source. This is done by bacteria living in symbiosis with plants who in exchange of sugar synthesize ammonia by the nitrogenase enzyme. In this presentation, the progress of synthesizing ammonia in a decentralized manner using an electrochemical process shall be discussed and in particular highlight some of the challenges.
There is a substantial very recent body of literature claiming ammonia synthesis by electrochemical routes and some of these data and their validity shall be critically reviewed. Often the ammonia is detected by the indo-phenol method which is an extremely sensitive method allowing for detection down to the ppb level. It is therefore mandatory that the amount of ammonia reported is quantified both in terms of turn over frequencies, but also in measured concentrations since contamination on the ppm level easily occurs leading to erroneous conclusions. Therefore, the experiments must also be followed up by proving that the nitrogen is coming from N2 and not by activation of some nitrogen compounds being present either in the catalysts or in the electrolyte. This is extremely important since the most difficult step in this process is the activation of the nitrogen molecule that is the second most stable molecule in nature. It shall be demonstrated that this can convincingly be done by using isotopically labelled 15N2. The ammonia synthesized can then subsequently be quantified using mass-spectroscopy, NMR or IR spectroscopy to prove that the source was indeed molecular nitrogen and not some other erroneous source of activated nitrogen. The advantage of using NMR or mass-spectroscopy shall be discussed and some of the tricks for measuring small amounts of ammonia in the presence of water shall be demonstrated. Examples of ammonia synthesis or lack of same for a number of catalysts tested shall be demonstrated.
(Invited) Atmospheric Ammonia Synthesis – Mechanism, Materials and Processes
Authors: Liu Bin 
Published: February 2020

Ammonia is a critical chemical that sustains the global food chain by feeding approximately 40% of world’s population. Ammonia can also be utilized as a clean fuel or energy carrier to power efficient energy conversion devices. However, ammonia production based on Haber-Bosch process is increasingly challenged by scalability and energy intensity (consuming almost 2% of the world’s energy). Ideally, feasible ammonia synthesis processes enabling intermittent operations at milder conditions and smaller scale, as well as the integration with renewable energy sources, will bring the technological breakthrough in order to better suit current societal needs.
In this talk, theoretical density functional theory (DFT) will be used to evaluate a class of novel alternative materials for N2 activation, ammonia formation and decomposition. Specifically, our recent work on transition metal or alloy-based nitrides (TMNs) will be discussed to show that the knowledge of molecular mechanism from theory is necessary and can lead to the formulation of guidelines to help identify appropriate materials and their optimizations. TMNs have been successfully demonstrated in stepwise, atmospheric ammonia synthesis in a nitridation cycle. Recent studies have also suggested that TMNs are also promising materials to catalyze N2, via electroreduction, to ammonia under ambient conditions. By following a Mars-van Krevelan mechanism, we identified that the nitride formation thermodynamics and nitrogen species diffusion kinetics under relevant process condition are both the key and will invoke the consideration of both aspects simultaneously in the nitridation-reduction cycle. To improve the TMN performance, the simple strategy to modify the electronic structures of TMN by alloying with other transition metals, targeting both bond formation and nitrogen transport within TMN, will be presented. Derived from our computational findings, bifunctional materials that are capable of efficient N2 activation and ammonia synthesis in synergy may hold the ultimate solution. Potential candidate materials that can be deployed for electrochemical or thermal ammonia production will be presented.
Electrosynthesis of Bio-Based Dicarboxylic Acids
Authors: Rauen Anna Lisa , Waldvogel Siegfried R. 
Published: February 2020

Currently, oil and gas are dominating feedstocks for bulk and fine chemicals. However, limited fossil resources and growing awareness for the environment requires sustainable alternatives [1]. One potential source for renewable raw materials is wood. In the pulping process of wood to cellulose, large amounts of lignin and also turpentine accumulate as a by-product. With the holistic use of waste streams in mind, lignin and the components of the turpentine fraction represent promising sources for carbon building blocks.

α-Pinene, the major compound of the turpentine fraction, can be oxidized to a biogenic dicarboxylic acid which finds a potential application as a hardener in bio-based thermosets. For a fully sustainable application, the necessity for renewable resources goes hand in hand with the demand for green chemical processes, such as electrosynthesis [2].
The key step of a possible oxidation sequence of α-pinene to bio-based dicarboxylic acids is successfully performed by electrocatalytical conversion of pinanediol to pinonic acid. To establish this transformation as a green method, we developed a simple, high-yielding protocol for the anodic oxidation of pinanediol, while maintaining of the intrinsic stereogenic information, at nickel oxidehydroxide anodes in water, the least hazardous of all solvents.
[1] C. Brandt,
Chem. Unserer Zeit
2002, 36, 214–224.
[2] A. Frontana-Uribe, R. D. Little, J. G. Ibanez, A. Palma, R. Vasquez-Medrano, Green Chem. 2010, 12, 2099–2199.

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Electrosynthesis of 2,1-Benzisoxazole from o-Nitrobenzaldehyde
Authors: Hosseini Seyyedamirhossein , Peters Dennis G 
Published: February 2020

Chemical synthesis of organic compounds is often a complex process that requires toxic catalysts, long reaction times, and many reagents. One example is the conventional synthesis of 2,1-benzisoxazole (BNZ). This compound has great importance for both pharmaceutical applications and as a starting material in the total synthesis of natural products.1 Chemical synthesis of this compound requires use of ruthenium and palladium catalysts, high pressure of carbon monoxide, and long reaction times.2 Also, the yield for the conventional chemical reaction is low, and there are no reports of yields higher than 50%.3

On the other hand, electrochemistry offers a clean and fast method for the synthesis of organic compounds. However, the electrosynthesis of BNZ has previously involved the use of a mercury pool cathode over a long reaction time, which makes the synthesis unfavorable.4 In the present work, the electrochemical behavior of o-nitrobenzaldehyde was studied in different solvent systems with the aid of cyclic voltammetry. Subsequently, the electrosynthesis of BNZ was accomplished with bulk electrolysis at a carbon cathode. Upon optimization, the yield of the BNZ reached 80% within a 1-hour electrolysis without any catalyst to facilitate the process.
References

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Electrochemical Functionalization of Methylarenes Initiated By Hydrogen Atom Transfer and Comparison to Electron-Transfer-Initiated Functionalization
Authors: Rafiee Mohammad , Stahl Shannon S. 
Published: February 2020

Aerobic oxidations catalyzed by N-hydroxyphthalimide (NHPI) are commonly utilized for the oxygenation of activated C–H bonds (allylic, benzylic, adjacent to heteroatoms).[i] NHPI undergoes proton-coupled oxidation to afford phthalimido-N-oxyl (PINO), which then mediates HAT from weak C–H bonds. In 1983, prior to the development of aerobic methods to generate PINO, Masui and co-workers demonstrated the ability to access PINO from NHPI under electrochemical conditions [ii] and site-selective oxygenation of the electrochemically generated radical using O2 as radical trap.[iii] Electrochemical PINO generation was utilized recently for scalable oxidation of terpenes[iv] and benzylic oxygenation of heterocyclic compounds.[v] In the latter reactions, metal-free electrochemical oxygenation overcomes the challenges encountered with chelating substrates that inhibit Co/NHPI-catalyzed aerobic oxidation reactions. Electrochemical oxidation of NHPI to PINO additionally presents the opportunity to trap organic radicals with reagents other than O-atom sources. This presentation will describe the first example of this concept, showing that iodine (I2) is an effective radical trap for electrochemical NHPI-mediated oxidation of methyl­arenes to benzyl iodides.
The method provides the basis for direct (in situ) or sequential benzylation of diverse nucleophiles using methylarenes as the alkylating agent. Voltammetric studies demonstrate that this mediated HAT mechanism for C–H iodination allows C–H oxidation to proceed with minimal dependence on the substrate electronic properties, contrasting benzylic C–H functionalization methods that proceed via direct electron transfer. The operating potential of the NPHI-mediated process is 0.5 – 1.2 V lower than that of direct electrochemical C–H oxidation.
[i]. Recupero, F.; Punta, C. Chem. Rev.
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[ii]. Masui, M; Hara, S.; Ueshima, T.; Kawaguchi, T.; Ozaki, S. Chem. Pharm. Bull. 1983, 31, 4209.
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[iv]. Horn, E. J.; Rosen, B. R.; Chen, Y.; Tang, J.; Chen, K.; Eastgate, M. D.; Baran, P. S. Nature
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[v]. Hruszkewycz, D. P.; Miles, K. C.; Thiel, O. R.; Stahl, S. S. Chem. Sci. 2017, 8, 1282.

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