bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Cathodic Behavior of Doped Pr2NiO4 Cathode for Solid Oxide Fuel Cell with Lsgm As Electrolyte
Authors: Xie Jing , Ban Shuai , Zhou Hongjun , Ishihara Tatsumi 
Published: February 2020

Solid oxide fuel cells (SOFCs) is now expectative as its highly efficient and the environmental friendly electric power generator for the next generation and now expectative for its application to the stationary field, such as power plants and home electricity-heat simultaneous generating systems, because of its high operating temperature and the flexibility of fuels. Unfortunately, cathode properties will drop seriously as the operating temperature decreases. One of the main subjects to overcome this problem is the development of novel cathode materials with high electrical conductivity and stability in the SOFC operating conditions. As reported, Pr2Ni0.71Cu0.24Ga0.05O4(PNCG) showed very good oxygen diffusivity, lower polarization resistance [1~3] and appropriate thermal expansion coefficient [4]. Therefore PNCG is a good candidate for IT-SOFC.
In the present study, various oxides were prepared by using the conventional solid-state reaction methods. XRD was employed to check the crystal structure of the products. The cell tested consists of PNCG cathode, La0.9Sr0.1Ga0.8Mg0.2O3 (LSGM) electrolyte and Ni-Fe bimetallic anode. For measuring power generating properties, pure O2 and humidified H2were used for oxidant and fuel, respectively. The temperature range is 773 K~1073 K, normal pressure, and 100 cc/min gas flow rate. The impedance spectra were measured to study the oxygen diffusivity and oxygen reduction reaction at cathode.
The XRD results indicate that the PNCG was obtained with K2NiO4 structure, no other oxides were found. When the cell voltage was 0.7 V, the cell power density was 484.2 mW/cm2 at 1073 K, 239.2 mW/cm2 at 973 K, 52.5 mW/cm2 at 873 K and 6.7 mW/cm2at 773 K, respectively. The cell with PNCG cathode exhibited reasonable cell performances among the operating temperature range. Figure 1 shows the power generation property of the cell using PNCG cathode.
The impedance spectra were measured too. The result was shown in figure 2. The impedance spectra were fitted with Zview software. Then theoretical calculation using the Adler-Lane-Steel and Dusty gas models were employed to analyze the oxygen diffusion and oxygen reduction reaction on PNCG.
Consequently, this study reveals that PNCG does function on improving catalytic property of cathode materials for its high surface exchange coefficient and oxygen diffusion coefficient. PNCG is a good candidate cathode for SOFC.
References
[1] X. Meng et al. Ceramics International B 41, (2015): 12107-12114
[2] J. Hyodo et al. Solid State Ionics 262, (2014): 889-892
[3] J. Hyodo et al. Solid State Ionics 220, (2013): 16-20
[4] J. Xie et al. Journal of Power Sources, 228, (2013): 229-236

Figure 1
Synthesis and Characterization of Oxygen Evolution Reaction(OER) Catalysts for Anion Exchange Membrane Electrolyzer
Authors: Lee Kyu Hwan , Choi Sung Mook , Jang Myeong-Je 
Published: February 2020

Hydrogen has recognized as a high energy density, efficient, and environmentally clean in a variety of renewable energy sources can be produced by an anion exchange membrane electrolyzer that has several advantages as use of non-precious metal oxide catalysts, high pressure operation, and high efficiency compared with other type electrolyzers.
The target of this study is the development of non-precious catalysts with high activity via simple and efficient synthesis method. The prepared OER electrocatalysts were characterized by various physicochemical analyses such as X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). Furthermore, to investigate electrocatalytic properties of prepared catalysts, we carried out electrooxidation activity measurements such as cyclic voltammetry (CV), linear sweep voltammetry (LSV), long-term stability test, and electrochemical impedance spectroscopy (EIS). The synthesized CuCoO4 series catalysts show a different tendency in physicochemical properties and OER activity with synthesis conditions as pH, heat treatment temperature, and drying method.

Figure 1
Preliminary Study of a Hydrogen-Vanadium Flow Battery
Authors: Dowd Regis Paul , Ying Andrew , Nguyen Trung Van 
Published: February 2020

Hydrogen-vanadium flow batteries offer a feasible solution for storing electrical energy from the grid or directly from renewable energy sources such as wind and solar. While charging, a hydrogen-vanadium flow battery stores energy in the form of hydrogen and vanadium (V). During discharge, hydrogen is consumed at the negative electrode and vanadium (V) is reduced to vanadium (IV) at the positive electrode. Vanadium systems demonstrate no issues with membrane fouling or metal dendrite formation.1 Additionally, vanadium solutions have low volatility, low corrosivity, and do not produce toxic vapors.1 Due to the relatively high cost of vanadium, the hydrogen-vanadium flow battery is attractive over the all-vanadium system due to the 50% reduction in the amount of vanadium solution required. Past research by Yufit et. al. has shown the feasibility of the hydrogen-vanadium flow battery and the importance of vanadium electrode wettability on fuel cell performance.1 Additionally, studies by Menictas et. al. also revealed crossover of vanadium species during operation of the vanadium-oxygen flow battery, sparking our interest in vanadium’s effect on the hydrogen electrode catalyst.2

In this study, we examine the performance of a hydrogen-vanadium flow battery when using interdigitated flow fields at both electrodes and a high surface area carbon nanotube electrode as the vanadium electrode. With a reference electrode placed in the vanadium side, we separate the cell performance into individual electrode performance. Using the half-cell results and electrochemical impedance measurements we identify the components and processes that have the greatest influence on the performance of the flow cell during discharge and charge. Additionally, we explore if crossover of vanadium through the polymer electrolyte membrane results in any negative effect on the platinum catalyst at the hydrogen electrode. This will be determined by employing electrochemical measurement techniques using a platinum rotating disc electrode and a 3-electrode arrangement. In turn, the effect of vanadium crossover to the hydrogen electrode will be investigated by measuring effective exchange current density and electrochemical active surface area (ECSA) of platinum when vanadium (IV) and vanadium (V) are present in the electrolyte.
References:

V. Yufit, B. Hale, M. Matian, P. Mazur and N. Brandon, “Development of Regenerative Hydrogen-Vanadium Fuel Cell for Energy Storage Applications,” Journal of the Electrochemical Society, 160(6), A856-A861 (2013).

C. Menictas and M. Skyllas-Kazacos, “Performance of vanadium-oxygen redox fuel cell,” Journal of Applied Electrochemistry, 41, 1223-1232 (2011).
(Invited) Revealing the Optimum Li-Mobility in Garnet Electrolytes
Authors: Brugge Rowena , Chater Richard John , Manalastas William Wang , Kilner John A. , Aguadero Ainara 
Published: February 2020

“Li-stuffed” garnet electrolytes can deliver the adequate Li-conductivity, safety and cycle life required for the commercialisation of high-energy density batteries (i.e. high voltage Li-ion and Li-metal based batteries). However, these garnet electrolytes, if they are not processed properly, suffer from severe moisture-sensitivity that leads to drastic
degradation of their transport and microstructural properties – a problem that has not been universally recognised in the field and that is impeding the achievement of the optimum performance of garnet electrolytes in Li-batteries. This is partially due to the Li-H Exchange taking place during the atmospheric degradation process that not only leads to a decrease in the Li transport number but also to the formation of insulating secondary phases (i.e. Li2CO3, LiOH) in the grain boundaries and interfaces. In fact, the integration of garnet electrolytes in Li battery devices has been delayed due to the high interfacial resistances at the lithium metal anode side which limits the performance to low current density cycling[1]. Again, this high interfacial resistance has been related to the formation of a Li2CO3 layer between the garnet and the Li-metal when not enough care is taken with the control of moisture during processing of the ceramics[2].
We have developed a unique setup that allows a strict control of the moisture during the processing and characterization of the garnets. The synthesis and processing of Li7-nxAx(n-1)xLa3Zr2O12 (A= Ga(III), Ge(IV), = lithium vacancy, VLiꞌ) garnets have been performed in a Ar-filled glove box with a high temperature furnace coupled to it. This has result in a three-fold enhancement in the total lithium-ion conductivity, up to 1.3 mS/cm at 24
°
C[3] and the performance of garnets with highly controlled microstructure with densities up to 98%. The intrinsic Li-mobility in garnets has been characterised by means of impedance spectroscopy and 6Li-isotopic labelling. The effect of the moisture-degradation on the charge carriers concentration and mobilities has also been analysed using a controlled exchange in D2O. To achieve this, a focussed-ion beam, secondary ion spectrometer has been used to detect all elements and their isotopes and yields the distribution of species in three dimensions on a nanoscale resolution, allowing the evaluation of the independent contributions of each isotope (6Li+, 7Li+, H+, D+) to the conduction process.

[1] S. Ohta, et al., J. Power Sources, 2013, 238, 53
[2] L. Cheng, et al., PCCP, 2014, 16, 18294
[3] C. Bernuy-Lopez, et al. Chem. Mater., 2014, 26, 3610
(Invited) The Role of Ionic Transport in Nuclear Waste Immobilization and Membrane Separations
Authors: Brinkman Kyle S 
Published: February 2020

Durable ceramic waste forms that incorporate a wide range of radionuclides have the potential to broaden the available disposal options and to lower the storage and disposal costs associated with advanced nuclear fuel cycles. Ceramic waste forms have also been studied because of their superior chemical durability and the ability to incorporate a broad spectrum of chemical species within the lattices. Recent work has shown that they can be produced from a melting and crystallization process similar to melter technology currently in use for High Level Waste (HLW) vitrification in several countries around the world. Cesium (primarily Cs137) is one of the more problematic fission product radionuclides to immobilize because of its volatility at high temperature and its tendency to form water-soluble compounds. Hollandite oxides of the form BaxCsyGa2x+yTi8-2x-yO16 (x=1.33, 1.04, 0.667, 0; y=0, 0.24, 0.667, 1.33), similar to materials used as Li battery cathodes are currently under evaluation for the immobilization of Cs. The phase formation, experimentally determined ionic conductivity, and propensity for elemental release were determined for substituted hollandites containing different levels of Cs. Implications for controlling the ionic transport in diverse applications of ceramic-ceramic composites ranging from mixed ionic and electronic conducting separation membranes to nuclear waste immobilization will be discussed.
Quantitative Nanostructure Analysis of Silver Vanadium Phosphorus Oxide (Ag2VO2PO4) Battery Material Using X-Ray and Electron Microscopy
Authors: Ge Mingyuan , Yan Hanfei , Huang Xiaojing , Xin Huolin L. , Liu Wenjun , De Andrade Vincent , Marschilok Amy C , Takeuchi Esther S , Chu Yong S 
Published: February 2020

With the state-of-art synchrotron-based X-ray and modern electron microscopy, the spatial resolution and measurement sensitivity have been significantly improved in analyzing materials’ nanostructure, by taking advantages of the high beam flux density or the source brightness. Associated with the ever brighter beam, it also brings the opportunity to investigate the beam effect to material structure modification, which is of significant interests in view of understanding the underlying physics, and it is also important to develop proper methodologies to use these state-of-the art probes to accurately characterize the intrinsic and extrinsic properties of materials.
In our work, we performed x-ray imaging experiment on single crystalline Ag2VO2PO4 battery material sample with a 15 nm resolution using the recently commissioned x-ray imaging capability at the Hard X-ray Nanoprobe Beamline at the National Synchrotron Light Source II. Probe-induced electrochemical reaction was observed, which was revealed by the Ag reduction as well as diffusion and re-distribution of Ag. In order to better understand the probe-induced electrochemical reactions, we also performed imaging experiments with other imaging methods: white-beam microdiffraction, transmission x-ray microscopy (TXM), and transmission electron microscopy (TEM). These probes deliver different levels of radiation does and provides different pathways for probe-induced structural modification. This presentation will elaborate and quantify the probe-specific structural modifications.
Electrochemically Formed TiO2 Nanotube Arrays Site Selectively Decorated with Porous Au Particles By a Controlled Dewetting-Dealloying Approach - a Platform for Efficient Photocatalytic H2 Evolution
Authors: Nguyen Nhat Truong , Altomare Marco , Schmuki Patrik 
Published: February 2020

In the last decades TiO2 has received large attention due to its ability to “photocatalytically” split H2O into H2 and O2. Under “open-circuit” conditions, noble metal-modified (mainly Pt, Au or Pd) TiO2 is needed for H2 photo-generation.1 Not only the presence but also the size, amount and distribution of the noble metal particles affect the photocatalytic efficiency of TiO2.2,3

In this contribution we show that a most effective way to control the size and distribution of co-catalytic nanoparticles deposited on ordered TiO2 nanotube arrays is a controlled sputter-dewetting process.4

For this, we first grow electrochemically highly-ordered arrays of short aspect-ratio TiO2 nanotube in a o-H3PO4/HF electrolyte.5 The tubes growth is based on a simple anodization of a Ti metal substrate in self-ordering electrochemical conditions, and the morphology of the formed tubular oxide structures can be simply adjusted by the experimental conditions. These arrays of TiO2 nanotubes are coated with sputtered Au and Ag films, and a following controlled thermal treatment is carried out that leads at the same time to Au-Ag alloying and thermal dewetting of the conformal metallic film, that is, the sputtered metals are converted into an array of orderly distributed alloyed Au-Ag nanoparticles.
By adjusting the sputtering conditions, we are able to selectively deposit the Au-Ag nanoparticles at the rim and/or within the cavity of the TiO2 nanotubes. Subsequently, we perform a dealloying process, consisting in the selective chemical dissolution of Ag in a HNO3 solution, this leaving behind nanoporous Au particles on/into the tubes. Compared to tubes decorated by conventional approaches, remarkably enhanced photocatalytic H2 production is obtained upon porousification of the embedded Au nanoparticles. These porous Au/TiO2 nanotube structures show a remarkable photocatalytic enhancement particularly when the Au porous particles are selectively formed at the rims of the tubes (“crown” position).
[1] K. Lee, A. Mazare, P. Schmuki, Chem. Rev.
2014, 114, 9385–9454.
[2] N. T. Nguyen, J. Yoo, M. Altomare, P. Schmuki, Chem. Commun.
2014, 50, 9653–9656.
[3] N. T. Nguyen, M. Altomare, J. E. Yoo, N. Taccardi, P. Schmuki, Adv. Energy Mater.
2015, doi: 10.1002/aenm.201501926.
[4] N. T. Nguyen, M. Altomare, J. Yoo, P. Schmuki, Adv. Mater.
2015, 27, 3208–3215.
[5] J. E. Yoo, K. Lee, M. Altomare, E. Selli, P. Schmuki, Angew.
Chem. Int. Ed.
2013, 52, 7514–7517.

Figure 1
Hydrogen Production By Photocatalytic Water Splitting Using Mixed Oxide Solid Solutions Under UV-Vis Light Irradiation
Authors: Duconge José J , García Abraham , Cotto María , Ortiz Dayna , Márquez Francisco 
Published: February 2020

Photocatalytic water splitting with generation of hydrogen is a green process that concerns activity of a semiconductor material under sunlight irradiation and ambient pressure and temperature. This process has been regarded as a promising solution to resolve the global energy and environmental problems. In this research, photocatalytic hydrogen generation by water splitting, H2O (l) → H2 (g) + 1/2 O2(g), has been studied on photocatalysts based on mixed oxide solid solutions (ZnCdFeCuS), synthesized by coprecipitation of different metal precursors. Iron and copper nanoparticles were incorporated as cocatalysts to enhance the photocatalytic activity of the ZnCd solid solution. The effect of the different synthesis parameters, including temperature, elemental atomic ratios, amount of S, Cu and Fe incorporated in the catalyst, and calcination temperature, on the photocatalytic production of hydrogen has been studied in order to determine the best experimental synthesis conditions. The catalysts have been characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), X-ray photoelectron spectroscopy (XPS), and BET.
The experiments of photocatalytic water splitting were performed in aqueous solution of the photocatalysts. Before use, the catalysts were either activated under a nitrogen flow of 300 mL min-1 at different temperatures (400, 700 and 900°C) for 2 hours. In all cases, the photocatalytic activity was measured by dispersing 50 mg of the catalyst in deionized water in an ultrasound bath at room temperature and atmospheric pressure containing 0.5 M Na2S and 0.03 M Na2SO3 as sacrificial reagents. The catalytic peak for the overall water splitting reaction occurs in a short pH range, typically 4-5.2 and for this reason, solutions were pH-adjusted. The reaction mixture was purged with N2(g) for 30 min and after that evacuated several times to completely remove the air prior the irradiation process. The water splitting reaction was conducted in a quartz reactor equipped with a water-cooling jacket. The reaction mixtures were irradiated at different light wavelengths (from 220 to 700 nm) using a solar simulator and appropriate cutoff filters in a static air atmosphere. The evolved gases were analyzed by GC-TCD, using N2 as carrying gas.
Transport Phenomena in Electrical Double Layer Capacitors with Highly Ordered 3D Porous Carbon Electrodes
Authors: Mei Bing-Ang , Pilon Laurent 
Published: February 2020

Electric double layer capacitors (EDLCs) store energy via ion adsorption in the electric double layer forming at the electrode/electrolyte interfaces in highly porous carbon electrodes. This charge storage mechanism is very fast and highly reversible resulting in large power density and long cycle life. Applications range from regenerative breaking for hybrid electric vehicles to the smart grid. The architecture of the carbon electrodes is known to have a significant effect on the performance of EDLCs. Unfortunately, experimental optimization can be time consuming and challenging due to the large number of design parameters. Numerical simulations could offer a faster and less costly alternative.
This study aims to demonstrate the use of numerical tools to simulate transient three-dimensional interfacial and transport phenomena in EDLCs with realistic electrode architecture. It also aims to derive design rules for EDLC porous electrodes. To do so, cyclic voltammograms were numerically generated for EDLCs consisting of electrodes with highly-ordered spherical carbon nanoparticles arranged in simple cubic (SC) or face-centered cubic (FCC) packing in LiClO4/propylene carbonate electrolyte. Simulations were performed for different carbon nanoparticles diameter, electrode thickness, and scan rate. The continuum model was based on the modified Poisson-Nernst-Planck model and accounted for (i) the Stern layer at the electrode/electrolyte interface, (ii) finite ion size, (iii) binary and symmetric electrolyte, and (iv) three-dimensional electrode morphologies. In all cases, the areal capacitance was independent of scan rate at low scan rate but decreased beyond a critical scan rate corresponding to the diffusion-limited regime when ion transport cannot follow the rapid changes in electric potential. The results indicate that the areal capacitance (in F/m2) increased with decreasing sphere diameter below 40 nm due to the increasing surface curvature resulting in larger surface electric field. In addition, FCC packing featured larger capacitance that SC packing thanks to larger surface electric field for given sphere diameter and low scan rate . However, the ion diffusion regime was reached at lower scan rates in FCC packing because of the higher turtuosity limiting the ion transport in the electrode.
(Invited) Interfacial and Transport Phenomena in Hybrid Pseudocapacitors
Authors: Pilon Laurent , Girard Henri-Louis , Mei Bing-Ang 
Published: February 2020

Electrochemical capacitors have attracted significant attention in recent years due to their promise as electrical energy storage devices for high energy and power applications. They are typically classified as either electric double layer capacitors (EDLCs) or pseudocapacitors depending on the energy storage mechanism. EDLCs store energy physically in the electric double layers (EDLs) forming near the electrode/electrolyte interfaces. Thus, EDLCs feature highly reversible charge storage and long cycle life. However, their energy density remains low compared with that of batteries. On the other hand, pseudocapacitors store energy via the electric double layers as well as via reversible oxidation-reduction (redox) reactions with or without insertion or intercalation. Pseudocapacitors tend to feature larger capacitances and energy densities than EDLCs because the amount of charge they can store is not limited by the surface area of the electrode/electrolyte interface. Finally, hybrid pseudocapacitors are devices combining a pseudocapacitive electrode made of a porous transition metal oxide (e.g., RuO2, MnO2, Nb2O5, MoO3) and an EDLC-type electrode typically made of porous carbon.
This invited talk will present recent advances in physical modeling of interfacial, transport, and electrochemical phenomena in pseudocapacitors. It aims to provide physical interpretation of cyclic voltammograms obtained experimentally either from hybrid pseudocapacitors or from pseudocapacitive electrodes using three-electrode systems. First, it will present a continuum model simultaneously accounting for (i) charge transport in electrodes and electrolyte, (ii) the dynamics of the electric double layer, (iii) steric repulsion due to finite ion sizes, (iv) redox reactions, and (v) intercalation. Second, it will report selected numerical simulations of CV curves for different electrode thickness and electron and ion transport properties in the electrodes and electrolyte, representative of actual situations. These results will be used to elucidate the respective contributions of faradaic reactions and electric double layer formation to charge storage in pseudocapacitors. Particular attention will be paid to the so-called b-value characterizing the power law evolution of the total current with respect to scan rate for a given potential. Special effort will be made to systematically compare model predictions with experimental data.