bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electrochemical Performance and Stability of Perovskite Structured Anode Materials for Intermediate Temperature-Solid Oxide Fuel Cells
Authors: Jo Su Yeon , Park Jun-Young 
Published: February 2020

Solid oxide fuel cells (SOFCs) are highly promising energy conversion devices that can directly convert chemical energy in a fuel to electrical energy. Because they have numerous advantages, such as high conversion efficiency, low pollutant output, and great fuel flexibility, SOFCs have been considered as next-generation clean energy generators.
Currently the state of the art anode material for SOFCs is Ni-YSZ cermet. This materials show excellent catalytic activity and stability for the H2 oxidation of hydrogen fuel at SOFC operation conditions. However, Ni-YSZ based anode cermets have a number of drawbacks in system where hydrocarbon fuel is used, such as carbon deposition and sulfur poisoning. In addition, Ni-based anodes suffer from instability upon redox cycling due to the volume expansion of the anode by the Ni oxidation to NiO. This drawbacks of Ni-YSZ cermet significantly may reduces the SOFC lifetime.
To overcome these drawbacks of Ni-YSZ based anode, we investigate Ni-free ceramic oxide material as alternative anodes. Developments of Ni-free anode, such as ceria, titanate and lanthanum chromite-based oxides, are required to meet various properties such as high electrochemical performances, tolerance to formation of carbon coking, thermal and redox stability. Among these materials, perovskite-structured materials have been explored to replace Ni-based cermet for SOFCs because they have high tolerance against the carbon deposition and sulfur poisoning with good electrocatalytic performances.
In this work, hence we investigate the performance and durability of Ni-free ceramic-based anode during redox cycles of IT-SOFCs. In addition, various transition metals are doped to cramic-based oxide materials to improve electrocatalytic activity, thus resulting in improving the SOFC performance. After the durability testing of SOFCs, electrochemical properties and physicochemical properties of Ni-free ceramic anode cells are investigate by using various analytic techniques such as EIS, SEM, TEM, and XRD.

References
[1] K.T. Lee, E.D. Wachsman, Science 334 (2011) 935.
[2] S. Park, J.M. Vohs, R.J. Gorte, Nature 404 (2000) 265.
[3] S. Tao, J.T.S. Irvine, Nat. Mater. 2 (2003) 320.
[4] K.B. Yoo, B.H. Park, G.M. Choi, Sol. St. Ionics, 225 (2012) 104.
[5] Ahmed D. Aljaberi and John T. S. Irvine. J. Mater. Chem. A. 1 (2013) 5868.
[6] Azra Yaqub, Cristian Savaniu, Naveed K. Janjuab and John T. S. Irvine, J. Mater. Chem. A, 1 (2013) 14189

Keywords: anode-supported solid oxide fuel cells, degradation mechanism, Ni-free anode material, redox cycling.
Modification of Carbon Electrodes with Electrochemically-Formed Dendrimer-Encapsulated Palladium Nanoparticles from Tributylmethylammonium Bis((trifluoromethyl)Sulfonyl)Imide Ionic Liquid
Authors: Lo Nai-Chang , Chen Po-Yu , Sun I-Wen 
Published: February 2020

In this study, the polyamidoamine (PAMAM) dendrimer-encapsulated metal nanoparticles-modified electrodes were prepared in a two-step electrochemical approach. First, dendrimer molecules were grafted onto carbon surfaces by electrochemical oxidation of the terminal amine groups of PAMAM dendrimer in aqueous solution[1]. Then the dendrimer-grafted electrodes were moved inside a oxygen- and moisture-free glove box and immersed in tributylmethylammonium bis((trifluoromethyl)sulfonyl)imide ionic liquid (Bu3MeN-TFSI IL)[2] containing Pd(II) ions. In the second step, the adsorbed metal ions (Pd(II)) were electrochemically reduced in a neat IL to form nanoparticles which were encapsulated by the PAMAM dendrimers grafted on the electrodes.
The modified electrodes were characterized using atomic force microscope (AFM), scanning electron microscope (SEM), transmission electron microscope (TEM) and energy-dispersive spectrometer (EDS). The stability and activity of the modified electrodes were studied in aqueous solution.

[1] 1. Kim, T. H.; Choi, H. S.; Go, B. R.; Kim, J. Electrochem. Commun.
2010,
12 (Copyright (C) 2015 American Chemical Society (ACS). All Rights Reserved.), 788-791.
[2] 2. Chen, P.-Y.; Hussey, C. L. Electrochim. Acta
2004,
49 (Copyright (C) 2015 American Chemical Society (ACS). All Rights Reserved.), 5125-5138.
The Effect of Catalyst Layer Deposition Thickness on DMFC Performance Via the Drawdown Method
Authors: Glass Dean , Prakash G. K. Surya , Olah George A. 
Published: February 2020

Catalyst deposition control is one of the overlooked areas of fuel cell fabrication and research that can affect the overall performance and cost of the fuel cell manufacturing. One such method that is seldom utilized in research is the drawdown method, a form of spreading. The effect of the different individual catalyst layer thicknesses and loadings on both the anode and cathode compartments of a direct methanol fuel cell (DMFC) was investigated separately. The drawdown method was performed at thicknesses varying from 1 mil to 8 mils with Pt/Ru loadings on the anode ranging from 0.25 mg cm-2 to 2.0 mg cm-2 and platinum loadings in the same ranges on the cathode. The membrane electrode assemblies (MEAs) with thicker individual layers (8 mil and 4 mil) performed better than the ones prepared with thinner individual layers (1 mil) in both the anode and cathode. The power density maxima for the different loading levels followed an exponential decrease of platinum utilization at the higher loading levels. The painted MEAs tended to display similar performance characteristics as the drawdown MEA layers closest to the thickness at the respective loadings, showing an effect on the overall fuel cell performance with respect to the individual layer thicknesses.
(Invited) All-Optical Measurement of Quantum Efficiency in Luminescent Materials and Its Application to Silicon Nanocrystals
Authors: Crowe Iain F , Halsall Matthew P , Gwilliam Russell M 
Published: February 2020

We present an all-optical technique for measuring the quantum efficiency (QE) of luminescent materials; and, although generally applicable, we apply it as an example to silicon nanocrystals. The concept of internal quantum efficiency (IQE) for a light emission process; the fraction of electron-hole pairs that generate photons inside a material is quite a simple one, and yet in practice this is very difficult to measure. In fact, all existing methods rely on an estimation of IQE from the externalquantum efficiency (EQE); the ratio of photons emitted to those absorbed, typically with the assumption that IQE tends to unity at low temperature. This is an over-simplification and requires further assumptions about the dielectric materials that the photons traverse.
An alternative approach was proposed earlier [1], in which both the light and heat, generated by the excitation process, are measured simultaneouslyas functions of a third variable, e.g. excitation laser power. However, experimental limitations such as reabsorption of light in the sample and recovery of a non-local thermal signal mean that only the EQE is ever really determined, albeit accurately [2].
In this contribution, we describe an all-optical (pump-probe) technique in which we balance the light leaving a local (μm-scale) region of excitation (by measuring μ-PL) with the heat generated at the focussed laser spot (by measuring changes in intensity of a near-IR reflected probe). Critically, our optical arrangement (three confocal signals in one microscope objective) combined with an advanced DSP ‘lock-in’ technique, permits measurement of ΔR/R to within 1 part in 106, corresponding to temperature changes on the mK scale. We present initial data on silicon nanocrystals, formed in glass cover-slips after ion implantation and thermal annealing, and discuss how the technique relates to a true measure of IQE with limitations and how it can be applied more generally to alternative material systems.
References
[1] D J Dunstan, ‘On the measurement of absolute radiative and non-radiative recombination efficiencies in semiconductor lasers’, J. Phys. D: Appl. Phys. 25 (1992) 1825 – 1828
[2] K R Catchpole et al, ‘High external quantum efficiency of planar semiconductor strucutres’, Semicond. Sci. Technol. 19 (2004) 1232 – 1235
(Invited) High Efficiency, Color-Tunable InGaN/GaN Nanowire Light Emitting Diode Arrays
Authors: Wang Renjie , Ra Yong-Ho , Mi Zetian 
Published: February 2020

The monolithic integration of red, green and blue (RGB) light-emitting diodes (LEDs) directly on a single chip is critically important for smart lighting and full-color display applications. The resulting color-tunable LEDs can exhibit excellent color rendering capability, high efficiency, and low power consumption, compared to conventional phosphor-based white LEDs. In this context, we have investigated the molecular beam epitaxial growth, fabrication and characterization of InGaN nanowire RGB LEDs monolithically integrated on a single chip, including Si and sapphire substrate. We have achieved controllable and tunable full-color light generation from InGaN LEDs. The correlated color temperature can be continuously varied in the range of 1900 K to 6800 K, while maintaining excellent color rendering index capability (CRI > 90).
In this work, RGB InGaN/GaN dot-in-a-wire LED arrays were grown on Si using a three-step selective area growth (SAG) technique, wherein blue, green, and red-emitting LEDs were grown in sequence. In this process, a SiOx mask layer was used to protect the previously grown devices and also to precisely define the growth position of each nanowire LED pixel. Tunable PL emission across the entire visible spectral range (~450 nm to 700 nm) can be readily achieved on a single Si wafer by varying the sizes and/or compositions of the dots. By separately biasing such lateral-arranged multi-color LED subpixels, the CCT value can be varied from ~1900 K to 6800 K, while maintaining relatively high CRI values (up to ~ 90, or higher).
We have further investigated the molecular epitaxial growth and fabrication of multi-color nanowire LED arrays on GaN template on sapphire substrate. In this process, a thin (~ 10 nm) Ti layer was utilized as the mask, and nanoscale growth patterns were defined by e-beam lithography. By controlling the nanowire diameters, multi-color emission can be achieved in a single epitaxial growth step. We have also demonstrated multi-color nanowire LEDs on sapphire substrate that can exhibit excellent current-voltage characteristics, high power operation, and reduced efficiency droop.
In summary, we have developed tunable, full-color InGaN nanowire LED arrays on Si and sapphire substrate by using special selective area growth techniques. Through controlled light mixing at the wafer-level, we have demonstrated color-tunable light emission with an unprecedented tuning range for the CCT, from 1900 K to 6800K, while maintaining excellent CRI values. The realization of electrically injected RGB InGaN nanowire lasers is being studied and will also be reported.
(Invited) on-Chip and Silicon-Compatible Er-Doped Aluminum Oxide Lasers
Authors: Bradley Jonathan D. B. , Purnawirman Purnawirman , Shah Hosseini Ehsan , Su Zhan , Magden E. Salih , Li Nanxi , Singh Gurpreet , Sun Jie , Adam Thomas N. , Leake Gerald , Coolbaugh Douglas , Watts Michael R. 
Published: February 2020

Erbium-doped lasers provide high power, narrow linewidth and thermally stable emission in the important 1.5-µm eye-safe and telecommunications band. By integrating such lasers on a chip we can realize cost-effective, compact and highly robust devices compared to fiber-based platforms. Furthermore, using a silicon-compatible fabrication approach allows for co-integration with silicon electronic/photonic devices and will open new applications for compact microsystems.
The presentation will cover our work on silicon-based erbium-doped aluminum oxide lasers (Al2O3:Er3+). Al2O3:Er3+ has recently received significant attention because of its broad emission, reduced clustering, and higher index, thus potential for more compact devices, compared to Er-doped silica. This has led to numerous demonstrations of amplification and lasing on chips using Al2O3:Er3+ as monolithic gain medium. As an important step towards silicon compatibility and exploiting wafer-scale lithography methods for high resolution cavity features, we have developed a silicon nitride-based Al2O3:Er3+ platform. Using such an approach, we have demonstrated a number of on-chip lasers, including distributed feedback, distributed Bragg reflector and microcavity devices. The talk will cover critical materials and design considerations towards realizing high performance lasers, including the influence of ion-ion clustering in the Al2O3 host, nanoscale film-thickness non-uniformities, and cavity Q factor optimization.
Development of Practical Sodium-Ion Batteries Using Amide Ionic Liquids: High Energy Efficiency, Excellent Cycleability and Wide Temperature Range Operation
Authors: Nohira Toshiyuki , Hagiwara Rika , Matsumoto Kazuhiko , Ding Changsheng , Fukunaga Atsushi , Sakai Shoichiro , Nitta Koji 
Published: February 2020

Over five years, we have been conducting R&D of sodium secondary batteries using amide ionic liquids as electrolytes. The new batteries intrinsically have high safety due to the nonflammability and nonvolatility of ionic liquids. Moreover, they can be operated in a wide temperature range of 273-363 K. We found that several types of FSA-based (FSA: bis(fluorosulfonyl)amide) ionic liquids exhibit superior properties for the application to sodium secondary batteries.
In the present paper, we first investigated the fundamental electrolyte properties for the binary Na[FSA]-[C3C1pyrr][FSA] (C3C1pyrr: N-methyl-N-propylpyrrolidinium) ionic liquid system. Then, NaCrO2 and hard carbon (HC) were selected as positive electrode and negative electrode active materials, respectively, and their fundamental charge–discharge characteristics were examined with coin-type half-cells. A 1.5 mAh coin-type full cell composed of HC/NaCrO2 exhibited excellent cycle properties, maintaining 90% of its initial capacity after 1000 cycles at 333 and 363 K. On the basis of these results, the 1.5 mAh full cell was fabricated and its performance was tested. It showed a high charge–discharge energy efficiency of 97.5% at 363 K and C/5 rate. Finally, we constructed a large-sized prismatic HC/NaCrO2full cell with a capacity of 27 Ah by a mass production process. We confirmed that its performance is comparable with that of the 1.5 mAh coin-type cell.
Acknowledgements
This study was partly supported by Advanced Low Carbon Technology Research and Development Program (ALCA) of Japan Science and Technology Agency (JST) and the Japanese Ministry of Education Culture, Sports, Science and Technology (MEXT) program “Elements Strategy Initiative to Form Core Research Center” (since 2012).
(Invited) The Power Flow Coloring: Concept and Implementation Methods
Authors: Matsuyama T. , Javaid S. 
Published: February 2020

In order to develop sophisticated systems with diverse components and versatile functions, it is a crucial and fundamental requirement to give a unique ID to each basic entity such as IP addresses in the Internet, social security numbers in welfare and health care systems etc.
This paper first introduce the concept of the power flow coloring, which gives a unique ID to each power flow between a specific power source and a specific power load.
Since the concept of the power flow coloring is attractive, there have been proposed several implementation methods that can be classified into three categories:
1. Power Line Switching
2. Power Routing (Store and Forward)
3. Synchronized Terminal Control
This paper gives an overview of these implementation methods and then describes our Peer-to-Peer cooperative distributed control method with several real world experimental results.
Analysis of Pulse-Reverse Nb Electropolishing with H2so­­
4 for Srf Cavities
Authors: Tian Hui , Reece Chalies E , Meyerson Melissa , McCord Cynthia 
Published: February 2020

The performance of superconducting radiofrequency (SRF) cavities is greatly affected by the topography of the interior surface, so it is imperative that the surface be clean metal as smooth as possible. Currently, the 1:10 volume ratio HF (49%) and H2SO4 (96%) electrolyte was widely used for high field SRF cavity production, the problem with using HF is that it is dangerous both to people and to the environment. A new method that has been developed to smooth the surface is pulse reverse electropolishing (EP). This method uses aqueous H2SO­­
4 as the electrolyte and alternating anodic and cathodic pulses to oxidize the niobium (Nb) and then remove the oxide from the surface [1]. Previous studies have shown that pulse reverse EP effectively polishes the surface of Nb SRF cavities [1,2].. In order to better understand polishing mechanism and optimize the operating parameter for cavity production, systematic electrochemical experiments have been carried out to further explore the oxide removal process, the effect of positive and negative pulse duration, pulse structure, off time between positive and negative pulses, concentration of H2SO­­
4, and determine optimum polishing parameters for reliable Nb SRF cavity production process, the results will be reported.
Ba0.5Sr0.5Co0.8Fe0.2O3-δ on N-Doped Mesoporous Carbon Derived from Organic Waste As a Bi-Functional Oxygen Catalyst
Authors: Wang Jian , Ciucci Francesco 
Published: February 2020

Developing cost-effective oxygen electrocatalysts is critical to the wide application of renewable energy technologies including fuel cells, electrolyzers, and metal-air batteries. In this work, we report Ba0.5Sr0.5Co0.8Fe0.2O3-δ (BSCF) on nitrogen-doped mesoporous carbon (NC) as a novel and highly-active bi-functional catalyst for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). The NC is prepared using organic waste, namely banana peels. The carbonization, heteroatom doping, and surface functionalization are achieved simultaneously during a facile synthesis process. The obtained NC is characterized by large mesopores with a specific surface area of 457.6 m2g-1. The electrochemical measurements reveal that, the current density of the BSCF/NC in 0.1 mol L-1 KOH reaches -3 at 0.74 V and 10 at 1.58 V vs. the reversible hydrogen electrode. Furthermore, the hybrid shows a smaller onset potential and larger current density towards both ORR and OER in comparison to composites made of BSCF and common commercial carbon supports, including acetylene black (AB) carbon, activated carbon (AC), and Vulcan XC-72 carbon. Besides enhancing the surface area and the dispersion of BSCF, the NC reduces the oxidation state of Co ion, likely giving the enhanced activity.
(Invited) Theoretical Analysis of Turbulent Mass Transfer with Rotating Cylinders
Authors: Newman John 
Published: February 2020

The data of Eisenberg1 and of Mohr2 provide an excellent basis for examining mass transfer in the system where the inner cylinder rotates within a larger stationary cylinder. The data are here correlated more carefully with respect to the dependence of the Stanton number on the Reynolds number, the Schmidt number, and the geometric ratio k of the inner cylinder radius to that of the outer cylinder. Three methods are deployed in this endeavor. Simple empiricism involves fitting the data according to the equation below where the parameters A, n, and p are functions of k. Enlightened empiricism expands on the traditional method of fitting the eddy viscosity as a function of the distance from the wall in the form of y
+ = (y/n)(t0/r)0.5, where t0is the shear stress at the solid wall. This method does not work well in a predictive manner for rotating systems or systems where the flow is in the direction of the curvature of the surface (as with Goertler vortices). Dissipation theory relates the local dissipation to its generation, transport, and decay, involving a parameter for the decay constant of the dissipation.
The electrochemical data of Eisenberg (with 1-k values from 0.1723 to 0.871) seem to be in the regime of wide gaps, while Mohr focused on thin gaps (1-k ranging from 0.0172 to 0.0839) to explore the failure of Eisenberg’s data to show an expected behavior where thin gaps blend into turbulent Couette flow. The dissipation theorem should provide a new method of understanding turbulent shear flow and a way of predicting the effect of varying the radius ratio.

*The author of this work is an Electrochemical Society Honorary Member

References

1. Morris Eisenberg, “Studies of Rates of Solid Dissolution and of Electrode Reactions at Rotating Cylindrical Bodies,” dissertation (Berkeley: University of California, 1953).
2a. Charles Milton Mohr, Jr., Mass Transfer in Rotating Electrode Systems, dissertation (Berkeley: University of California, 1975).
2b. Charles M. Mohr, Jr., and John Newman, Mass Transfer in Turbulent Flow between Rotating Cylinders with Small Separation Gaps. Berkeley: Lawrence Berkeley Laboratory, 1976. LBL-5136. Apparently never published.

Figure 1
(Invited) All-Electronic Sensing of Single Molecule Dynamics Using Carbon Nanotube Devices
Authors: Collins Philip G. 
Published: February 2020

Single-molecule techniques eliminate ensemble averaging to reveal the mechanisms, timing, and energetics of individual chemical and biochemical events. Over the past decade, single-molecule science has flourished as new techniques have adopted fluorescent probes, optical traps, and scanning probe microscopy to access the single-molecule limit. Recently, carbon nanotube transistors have been added to this toolkit of single-molecule techniques. As electronic transducers, single-walled carbon nanotubes have the sensitivity to detect single molecular events [1] and the bandwidth to resolve microsecond-duration transients and intermediate states [2]. These characteristics provide exciting new opportunities to monitor and understand complex catalytic cycles such as the biochemical reactions of enzymes.
For example, the single molecule kinetics of the Klenow fragment (KF) of polymerase I have recently been studied by bioconjugating KF to nanotube transistors. Continuous recordings of polymerase as it processes various DNA templates have extended through >10,000 bond-forming events, providing new insights into the processivity, kinetic variability, and tolerance of polymerase toward synthetic dNTP analogs [3,4]. In addition to the kinetics, signals generated with some analogs revealed conformational states that do not occur with native dNTPs, helping to explain polymerases’ tolerance for incorporating dNTP analogs. The high resolution of the electronic records illuminate new aspects of polymerase’s catalytic cycle and suggest new opportunities for all-electronic DNA sequencing.
[1] Y. Choi, et. al., “Single-Molecule Lysozyme Dynamics Monitored by an Electronic Circuit,” Science
335, 319 (2012).
[2] M.V. Akhterov, et. al., "Observing Lysozyme Closing and Opening Motions by High-Resolution Single Molecule Enzymology." ACS Chemical Biology
10, 1495 (2015).
[3] T.J. Olsen, et. al., “Electronic Measurements of Single-Molecule Processing by DNA polymerase I (Klenow fragment),” JACS
135, 7855 (2013).
[4] K.M. Pugliese, et. al., "Processive Incorporation of Deoxynucleoside Triphosphate Analogs by Single-Molecule DNA Polymerase I (Klenow Fragment) Nanocircuits." JACS
137, 9587 (2015).