bluuebunny/crossref_metadata_2025_split huggingface dataset:
New Membranes for Redox Flow Batteries Based on Heteropoly Acid-Polymer Composites
Authors: Kushner Douglas I. , Motz Andrew R , Kuo Mei-Chen , Kusoglu Ahmet , Herring Andrew M. , Weber Adam Z. 
Published: February 2020

Redox flow batteries (RFBs) remain one of the most promising technologies that are actively explored for grid-scale energy storage from discontinuous power sources such as wind and solar.[1] Proliferation of RFB technology has resulted in a need for continued development and understanding of new redox couples and improved separator membranes for RFB operation, while reducing cost. Membranes employed in RFB technology are largely comprised of the perfluorosulfonic acid (PFSA) family (e.g. Nafion, Aquivion, and 3M PFSA) which own their functionality to the phase separated structure composed of ionically conductive hydrophilic domains distributed within an inert and mechanically stable hydrophobic matrix.[2] PFSA membranes are also susceptible to high crossover of redox active species, leading to parasitic losses in capacity that can only be solved by the development of highly selective separator membranes.
In this work, we report our progress in developing membranes that exhibit high selectivity by employing heteropoly acid (HPA) ion conductors that have been covalently tethered to the backbone of a polymer support. HPA-loaded membranes are promising due to the highly mobile protons associated with the HPA molecule[3] alongside the hydrophobic polymer that provides mechanical strength that is capable of preventing crossover. PFSA membranes were used as a baseline to access the quality of the newly developed HPA-loaded membranes by measuring the selectivity which involves measurement of the membrane conductivity and permeability. The HPA-loading was varied on a mass base in order to evaluate the trade-offs between increased membrane conductivity, which tends to occur with increased permeability of redox active species. Selected membranes were subjected to cell testing in a RFB based on the iron-hydrogen to gauge cell performance.
References:

Perry, M.L. and A.Z. Weber, Advanced Redox-Flow Batteries: A Perspective. Journal of the Electrochemical Society, 2016. 163(1): p. A5064-A5067.

Kusoglu, A. and A.Z. Weber, New Insights into Perfluorinated Sulfonic-Acid Ionomers. Chemical Reviews, 2017. 117(3): p. 987-1104.

Motz, A.R., et al., Heteropoly acid functionalized fluoroelastomer with outstanding chemical durability and performance for vehicular fuel cells. Energy & Environmental Science, 2018. 11(6): p. 1499-1509.

Acknowledgements:
This study was funded with support of the U.S. Department of Energy under contract number DE-AC02-05CH11231 as sub-contract under Colorado School of Mines and United Technologies Research Center.
Innate Voids of Halloysite Enabling High-Volumetric Density Anodes for Silicon/Graphite Composites
Authors: Yeom Su Jeong , Lee Cheol Min , Kang Sujin , Ryu Jungki , Lee Hyun-Wook 
Published: February 2020

Silicon (Si) has been considered as a prospective anode material in lithium-ion batteries (LIBs) due to its exceptional high capacity and energy density than the commercialized carbon-based materials. However, volume expansion (~380%) caused by alloying chemistry of silicon affects the deterioration of electrodes and battery performance. To minimize these drawbacks, the fabrication of Si/graphite composite electrodes has emerged as a promising anode since graphite anodes possess less volume expansion (~10%) with a porous structure that contributes to the accommodation of the electrode level for Si expansion. It is well known that the specific capacity and cyclability would conflict in the composite anode as increasing silicon contents. With this interpretation, previous studies reported that the theoretical limit of Si contents in the composites was approximately calculated as 15% with a numerical optimization considering electrode porosity, expansion of active materials, and so on.
Considering aforementioned issues, we propose a novel method to enhance the energy density of the composite electrode by increasing the portion of Si by use of halloysite containing native voids in the structure, resulting in less volume expansion. As the production cost should be considered for practical application, we selected silicon nanotubes (SiNT) that derived from natural halloysite clay which is widely distributed in the earth crust. With facile and cost-effective synthesis process, the synthesized SiNT has less volume expansion (~200%). From the careful investigation via in-situ transmission electron microscopy, we found the optimal composition of SiNT in the silicon/graphite composites to overcome the limited volumetric density of the anodes. The physical and chemical properties, and battery performances will be discussed in detail in this presentation.
Electro-Oxidation of New Feedstocks to Value Added Chemicals
Authors: Boyd Michael James , Hahn Christopher , Jaramillo Thomas F. 
Published: February 2020

Today a large fraction of plastics and other material products come from the refinement of fossil fuels. With the potential volatility in fossil fuel availability in the future there is a need for alternative sustainable means of producing the products we use on a daily basis. Electrochemical oxidation of biomass/biomass-derivatives to value-added products is one such alternative, and can be coupled with renewable energy to reduce its carbon footprint.
In the present work we explore the electro oxidation of several unconventional electrochemical feedstocks: benzyl alcohol, glycerol, and methane. The activity of ionic materials (e.g. transition metal oxides, sulfides, phosphides) for the previously mentioned reactions is investigated and compared to that of platinum and gold. XPS and XRD are used to determine the phase and oxidation state of these ionic materials to elucidate the active site for said reactions. Meanwhile NMR is used for the detection and quantification of liquid phase products as a function of electrolyte pH, applied potential, and time to determine catalyst activity and selectivity.
Electro-Oxidation of Furans to Value-Added Chemicals
Authors: Roman Alex , Hasse Joseph , Medlin Will , Holewinski Adam 
Published: February 2020

Aqueous electrochemistry presents a unique platform for the valorization of biomass-derived oxygenates through rearrangements involving H or O atoms under ambient conditions. In addition, the electrochemical environment can alter product distributions and efficiencies in comparison to analogous thermochemical routes. For example, oxidation product selectivities can vary with potential by changing the surface coverage of hydroxyl groups and/or through the stabilization of products requiring electron transfer as opposed to neutral atom transfer steps.
This study focuses on characterizing the partial electro-oxidation of furfural and HMF under acidic conditions on various noble metal catalysts. These biomass-derived model compounds are derived from the acid-catalyzed conversion of lignocellulosic feedstocks and can yield value-added products such as furoic acid,maleic acid, and furan-dicarboxylic acid. A differential “flow-through” electrochemical reactor was paired with membrane-inlet mass spectrometry (MIMS) and LC-MS. We analyze the partial electro-oxidation of furans under a variety of conditions and discuss trends in product distributions as they pertain to possible reaction pathways. Ongoing work involves investigation of the reaction mechanisms through isotopic labeling experiments and electrochemical ATR-FTIR.
Tailoring Color and Surface Morphology of Electrodeposited Chromium By Application of Pulsed Current
Authors: Leimbach Martin , Tschaar Christoph , Zapf David , Kurniawan Mario , Schmidt Udo , Bund Andreas 
Published: February 2020

The electrodeposition of chromium layers for decorative purposes plays an important role in the surface finishing industry, especially for applications in sanitary, automotive, plating on plastics and similar fields. As the use of conventional hexavalent chromium based electrolytes is strongly restricted in several countries,1 the demand for alternative plating systems increased during the last years. The most promising alternative is the electrodeposition from trivalent chromium based electrolytes considering environmental safety, quality of the deposits and cost issues.2 Commercially applicable processes are already known since several decades.3 However, trivalent chromium based processes cannot fully meet the requirements on surface appearance of the layers.4 This is crucial for the above mentioned applications as slight differences in color can have a high impact on final implementation of the plated parts.
In this work chromium layers plated from different electrolytes were characterized by colorimetry, SEM and AFM. A relation between optical appearance and surface morphology was found and supported by a model based on the theory of light scattering on rough surfaces.5 In case of chromium(III) sulfate based electrolytes, grain size and roughness increase with increasing layer thickness, leading to a color shift from blueish to yellowish. To achieve a blueish appearance while having sufficient resistance against corrosion and wear, a fine-grained surface structure has to be obtained at high layer thickness. By application of pulsed cathodic current, grain growth is suppressed and nucleation is re-initiated at each current pulse, giving a surface grain size of 60 to 100 nm. Up to a chromium thickness of 200 nm, the color value still in the blueish range (b* < 0 in the L*a*b* color system). However, special characteristics of chromium electrodeposition from trivalent solutions have to be considered for choosing suitable pulse parameters in large scale applications.

European Chemicals Agency, Authorisation List, EC No. 215-607-8, 231-801-5, 231-889-5, 231-906-6, 232-140-5, 232-143-1, 234-190-3, 236-881-5.

Z. X. Zeng, A. M. Liang, and J. Y. Zhang, Recent Pat. Mater. Sci.,
2 (1), 50 (2009).

S. L. Handy, C. F. Oduoza, and T. Pearson, Trans. IMF,
84 (6), 300 (2006).

D. L. Snyder, Plat. Surf. Finish.,
90 (11), 34 (2003).

M. Leimbach, C. Tschaar, D. Zapf, M. Kurniawan, U. Schmidt, and A. Bund, J. Electrochem.
Soc.,
166 (6), D205 (2019).
Segregation in Aluminum-Zirconium Alloys, Electrodeposited from Ionic Liquids, and Its Modification By Pulse Plating
Authors: Freydina Evgeniya 
Published: February 2020

It is quite typical for aluminum-zirconium alloys, obtained by electrodeposition in chloroaluminate ionic liquids, to have two or more distinct phases with different Zr concentrations. The Zr content in one phase can be several times higher than in the other. In the present work we have studied this segregation in [EMIM]Cl*AlCl3 ionic liquid. Factors like temperature, current density, agitation, and concentrations of both zirconium and aluminum in the electrolyte were investigated.
A proposed mechanism for this phenomenon is based on a possibility of two different pathways of zirconium reduction. One pathway is a 4-electron process, taking Zr4+ directly to metal. Another way is a 2-electron reaction via intermediate Zr2+ ions formed in the solution. The difference between these pathways includes variations in chloride ions concentration in the vicinity of the electrode surface, as well as variations in charge and structure of the double layer.
The above variations exist only near the cathode surface, and have a limited life time. One approach to eliminating the segregation in the alloy is to utilize pulsed electrodeposition methods, allowing re-mixing and equilibration of the electrolyte during the off periods. As expected, shorter pulses and longer off times lead to more compositionally uniform deposits.
Figure 1. Backscatter SEM image of a cross section of Al-Zr deposit. Light areas are zirconium-rich.

Figure 1
Direct Electrocatalytic Conversion of CO2 to Chemicals over Single Atom Catalysts
Authors: Liu Di-Jia 
Published: February 2020

Carbon dioxide emission from fossil fuel combustion has generated an on-going debate on its impact to the global environmental and ecological systems. New carbon capture, sequestration and conversion technologies are widely pursued as potential solutions to mitigate the concerns. The electrochemical CO2 reduction reaction (CO2RR) to hydrocarbon fuels and chemicals using renewable electricity offers an attractive “carbon-neutral” or even “carbon-negative” mitigation strategy. CO2 is an inexpensive carbon source and can be used as a feedstock for producing high value chemicals. Key challenges facing the current CO2RR electrocatalysis include: a) how to improve energy efficiency by reducing the overpotentials; b) how to increase the process selectivity by enhancing a single-product Faradaic efficiency (FE); and c) how to lower the system operating cost by prolonging the catalyst stability.
Argonne National Laboratory through collaboration with Northern Illinois University recently developed a series of highly active and durable single atom catalysts (SACs) for CO2RR prepared using a robust synthesis method over the commercial carbon support. The new electrocatalysts offer the several advantages including: a) direct conversion to C2 (C2H5OH and CH3CO2H) and C3 (C3H6O) chemicals in one-step electro-catalytic reaction without secondary upgrading; b) higher than 90% FE by suppressing the byproduct formation; c) high energy efficiency with the onset potential as low as 0.4 V observed for ethanol conversion; and d) good stability with no sign of activity loss during extended hours of chronoamperometry measurement.
In this presentation, we will discuss the structure-function relationship of the new SACs with particular emphasis on CO2 to ethanol conversion. We will also share the mechanistic insight on catalysis as the catalyst transitioning from SAC to metal cluster. The catalyst performance in terms of FE, onset potential and durability will also be reported, combined with the catalyst structural properties obtained from various conventional and advanced characterization tools.

Acknowledgement: The work performed at Argonne National Laboratory is supported by Office of Science, U.S. Department of Energy under Contract DE-AC02-06CH11357.
Ion-Implanted Photoresist Stripping by Using Organic Solvents
Authors: Oh Eunseok , Lim Sangwoo 
Published: February 2020

In the ion implantation process, accelerated ions attack not only target materials but also photoresist, causing deformation of the molecular structure of the photoresist. It is difficult to remove crust layer formed by ion implantation in the standard photoresist removal methods. A typical method of removing high-dose ion-implanted photoresist is to use plasma ashing followed by the treatment in the mixture of hot sulfuric acid and hydrogen peroxide [1]. However, this process etches III-V semiconductors and dielectric materials [2]. Therefore, in this study, organic solvent-based mixtures were developed to remove high-dose ion-implanted photoresist without damaging the substrate.
Trench-patterned GaAs was used as a substrate and KrF photoresist was coated on trench patterned GaAs. Then, P+ ion implantation with a dose of 5×1015 ions/cm2 was conducted on the photoresist. A mixed solution of dimethyl sulfoxide (DMSO) and acetonitrile (AcN) (DMSO: AcN = 6: 4) was used to remove the ion-implanted photoresist and 1 vol% HCl or HF was used as an additive. Photoresist removal was measured using an optical microscope and in-situ MIR-FTIR.
When a mixed solvent of DMSO and AcN was used to remove ion-implanted photoresist, the photoresist was not completely removed and the residue and crust remained on the trench-pattern (Fig. 1). In order to improve the removal efficiency of ion-implanted photoresist, 1 % HCl or HF was added to DMSO+AcN solution. When 1 % HCl was added to the DMSO+AcN solution, the ion-implanted photoresist with an implantation energy of 30 and 50 keV was completely removed without residue. However, when the ion implantation energy was 70 keV, the photoresist crust was not removed in DMSO+AcN+HCl solution. When 1 % HF was added to DMSO+AcN solution, the ion-implanted photoresists was completely removed regardless of the ion implantation energy. Removal performance was quantitatively analyzed by in-situ MIR-FTIR as shown in Fig. 2. First, the ion-implanted photoresist was not removed more than 40 % for 10 min in DMSO. In DMSO+AcN solution, most of the photoresist was removed in 6 min, and all photoresist was removed in 4 min when DMSO+AcN+HCl was used. In the case of DMSO+AcN+HF, all of the ion-implanted photoresists were completely removed in 2 min and 30 s. Therefore, it is confirmed that DMSO+AcN+HF solution removes ion-implanted photoresist more quickly and effectively than other solutions used in this study. In addition, it is suggested that the largest interaction energy between DMSO+AcN+HF and the ion-implanted photoresist resulted in improvement of the removal efficiency of the photoresist.
References
[1] K. Kinoshita and P. Engesser, ECS J. Solid. State. Sc., 2, Q34 (2013).
[2] O. Louveau, D. Louis, M. Assous, R. Blanc, P. Brun, S. Lamy and E. Lajoinie, Microelectron. Eng., 61–62, 867 (2002).

Figure 1
(Invited) Challenges and Opportunities for Selective Area Processing in High Volume Manufacturing (HVM)
Authors: Sharma Kashish , Lemaire Paul , Nardi Katie , Hausmann Dennis 
Published: February 2020

In the recent years scaling approach to Moore’s law has slowed, there is longing for innovations in processes, design, tools, and materials. Selective deposition is one of them which has been used in various forms, most communally, metals on metals in the semiconductor industry. More advanced forms of selective area process such as metals on dielectrics, dielectrics on metals and dielectrics on dielectrics are making some progress at the industrial level for integration at HVM level. Since it has the potential to reduce the number of lithographic and etch steps in the manufacturing flow, it has been pursued actively at academic as well as at an industrial level.
In this talk, we will explore the selective processing applications which are driving the driving the semiconductor industry to look beyond conventional top-down processing. Applications where selective deposition are needed will be discussed. We will then look at the bottlenecks which needs to be addressed for selective processing technique to become a high volume manufacturable (HVM) process. The challenges and opportunities for HVM will be presented with an emphasis on the need for low defectivity, low cost, high throughput, repeatable, processes that can be applied across a 300 mm wafer without the loss of unit film properties. We will discuss some approaches that Lam Research is taking to meet these requirements, and also where innovation is still needed. Through this presentation, we hope to bring synergy and accelerate innovation in HVM-compatible selective processing.
Growth Kinetics of Magnesium Silicide Formation Via Reaction of Mg Gas and Si Substrates
Authors: Li Jiaqi , Sandhage Kenneth 
Published: February 2020

The thermal, electrical, optical, and chemical properties of magnesium silicide (Mg2Si) have led to consideration of this semiconducting material for use in thermoelectric, optical, sensor, corrosion mitigation, and other applications. The relative non-toxicity and earth-abundant nature of the constituent elements of this silicide are also attractive characteristics. One approach for generating patterned magnesium silicide structures for use in devices is the direct conformal reaction of patterned silicon structures with magnesium gas. The kinetic mechanism controlling such conformal gas/solid reaction will be discussed in this presentation.
The rate of thickening of magnesium silicide films, via the reaction of magnesium gas with planar silicon single crystal substrates, has been examined via measurements of mass change (∆m/A) and film thickness (∆X from SEM analyses of reacted cross-sections) as a function of time at 600oC. To avoid oxidation during such reaction, experiments were conducted within metal ampoules that had been carefully sealed in an argon atmosphere. Upon heating of the sealed ampoules to 600oC within an argon atmosphere tube furnace, magnesium gas (generated from solid magnesium within the ampoule) migrated to, and underwent reaction with, the planar silicon substrate. Measurements of ∆m/A vs. time and ∆X vs. time were both consistent with a parabolic rate law for the thickening of the Mg2Si layer, with the rate constants from both types of measurements in good agreement. Variations in the magnesium gas diffusion distance, and in the orientation of the starting silicon single crystal, were found to have negligible influence on the reaction kinetics. Such kinetic data were consistent with Mg2Si formation controlled by solid-state diffusion through the Mg2Si product layer. Inert marker experiments (using MgO particles) were used to determine the dominant interface at which new Mg2Si formed, and to evaluate the associated diffusing species controlling such formation. Kinetic analyses from this solid/gas reaction study will be compared to prior work on the formation of Mg2Si via solid-state reaction of magnesium with silicon.

Figure 1
Electrochemical Studies of One-Pot Synthesized Tetragonal Hausmannite Manganese Oxide/ Nitrogen-Doped Reduced Graphene Oxide Nanohybrid for Supercapacitor Applications
Authors: Makgopa Katlego , Ratsoma Mpho Sofnee 
Published: February 2020

The increasing consumption of fossils fuel accompanied by related carbon emissions and complex set of issues associated with the generation and use of electricity has raised an urgent need for reliable, renewable and sustainable energy alternatives [1]. Remarkable progress made in nanoscience and nanotechnology brought inspiration for further development of new technologies in electrochemical energy storage. Supercapacitors (SCs) have emerged as a fast-rising class of energy storage technology and have received tremendous attention for potential applications in high-power sources [1,2]. Thus, manipulation of nanostructured materials became an important approach for the improvement of energy storage properties in SCs. Up to now, various synthetic methods have been established to improve the electrode materials for SC applications. Carbon nanomaterials such as carbon nanotubes (CNTs), graphene and graphene oxide (GO) have been widely used and modified to enhance their energy storage performance in SCs. Recently, much interest has been devoted to the doping of carbon materials to improve the performance of SC devices. Manganese oxide-based electrode materials characterized by their high theoretical specific surface area (1370 m2 g-1), high theoretical specific capacitance (1100 to 1300 F g-1), low-cost, abundance and environmentally friendly in nature, have attracted significant interest as active electrode materials for SCs. Although intensive study has been done on the MnO2-based pseudocapacitor, tetragonal hausmannite manganese oxide, Mn3O4, has received limited attention in SCs application [3]. Among various synthetic methods of synthesizing carbon/metal oxides nanohybrids, hydrothermal reduction of metal salts in the presence of carbon material is widely used, due to the simple operation and the low cost.
This work present, one-pot synthesis of nitrogen-doped reduced graphene oxide decorated with hausmannite manganese oxide (N-rGO/Mn3O4 nanohybrid) and the study of its electrochemical energy storage performance for supercapacitor application. The microscopic and spectroscopic characterization of N-rGO/Mn3O4 nanohybrid and its precursor materials were acquired using SEM, EDX, Raman and XRD whereas the electrochemical characterization were acquired using cyclic voltammetry (CV), galvanostatic charge-discharge (GCD) and electrochemical impedance spectroscopy (EIS).