bluuebunny/crossref_metadata_2025_split huggingface dataset:
(Invited) Impact of Nafion Dispersion Morphology on Fuel Cell Performance and Durability
Authors: Kim Yu Seung , Welch Cynthia , Hjelm Rex , Mack Nathan , Johnston Christina , Choi Baeck , Langlois David A. , Lee Kwan-Soo , Orler Edward Bruce , Labouriau Andrea , More Karren , Xu Hui , Willey Jason , Mittelsteadt Cortney K 
Published: February 2020

Los Alamos National Laboratory fuel cell team has discovered that Nafion dispersion morphology in dilute liquid media ca. solid content: 2.5 wt.% has distinctive characteristics, depending on dispersing fluid:[ref. 1] Small angle neutron scattering (SANS) and 19F NMR analysis indicated (i) a well-defined cylindrical dispersion in polyhydric alcohols, (ii) a gel particles that have as open network structure with sufficiently sparse physical network connections in some aprotic dispersing fluids, and (iii) a less-defined highly solvated large particle in water-monohydric alcohol mixtures.
In this talk, we present the impact of dilute Nafion dispersion morphology on film/electrode formation, fuel cell performance and durability. Following subjects will be discussed with some details:
1. Change of particle morphology and gelation behavior of Nafion dispersion during evaporation process (Fig.1).[ref. 2]
2. Characterization of fuel cell electrode by microscopy and electrochemical methods.
3. Impact on fuel cell initial and long-term performance during potential cycles.[ref. 3]
Other critical effects including mechanical toughness of dispersion-cast membranes and electrode reaction uniformity [ref. 4] will be also discussed at the meeting. This presentation will give some insights on recent progress of engineering production and processing of perfluorinated sulfonic acid ionomers and their application for fuel cell membrane and electrode processing.
Acknowledgment U.S. Department of Energy Fuel Cell Technologies Program (Dr. Dimitrios Papageorgopoulos)
References 1. Welch, C.; Labouriau, A.; Hjelm, R.; Orler, B.; Johnston, C.; Kim, Y. S. ACS Macro Letters, 2012, 1, 1403-1407. 2. Kim, Y. S. Welch, C. F. Hjelm, R. P. Mack, N. H. Labouriau, A. Orler, E. B. Macromolecules 2015, 48, 2161-2172. 3. Kim, Y. S. Welch, C. F. Mack, N. H. Hjelm, R. Orler, E. B. Hawley, M. Lee, K. S. Yim, S.-D. and Johnston, C. M. Phy. Chem. Chem. Phy. 2014, 16, (13) 5927-5932. 4. Choi, B., Langlois, D. A. Mack, N. Johnston, C. M. Kim, Y. S. J. Electrochem. Soc. 2014, 161 (12), F1154-F1162.

Figure 1
Irrigation System Using Photovoltaics and Lithium Ion Batteries for Energy Storage
Authors: Moss Eugene Newton , Oladimeji Charles , Moss Pedro L. , Weatherspoon Mark H 
Published: February 2020

Typically, energy consuming systems are run off the traditional grid. However, there are remote areas of the United States that don’t have access to the traditional grid and in those places, there is a need for photovoltaic generation to supply those electricity needs [1].The use of photovoltaics along with lithium batteries for storing excess energy has increased due to the need for renewable energy as a viable source of electricity. Such energy storage systems (ESS) are useful for complex irrigation systems that assist in the cultivating of the United States food supply [2]. Without the ESS systems, maintaining a stable economy may be difficult in extreme cases.
The object of this research will be to construct a virtual photovoltaic generation system that is capable of powering an irrigation system, and it will also be used in tandem with a lithium-ion battery storage system. The focus of this irrigation system will be to water a tomato farm in the Florida climate. The work will be performed in a virtual environment using a modular approach to a system-level design that simulates the behavior of the photovoltaic system and the degradation of the lithium-ion battery pack. Ultimately, these results suggest the necessary components for a real photovoltaic and battery operated system require the optimally sized photovoltaic panel and inverter connected to a watering pump. The PV panels convert solar energy to electrical energy with DC current and the inverter converts DC current to AC current required to run the pump. In addition, Additional information from hygrometer readings and weather profile also would be needed with a optimizing algorithm to ensure efficient irrigation operation.

Acknowledgment

This work was supported by the FREEDM ERC program of the National Science Foundation under award number EEC-08212121.

References

Louy Qoaider, Dieter Steinbrecht, Photovoltaic systems: A cost competitive option to supply energy to off-grid agricultural communities in arid regions, Applied Energy, Volume 87, Issue 2, February 2010, Pages 427-435, ISSN 0306-2619

M. Arifujjaman, A comprehensive power loss, efficiency, reliability and cost calculation of a 1 MW/500 kWh battery based energy storage system for frequency regulation application,

Figure 1
A Single Material Battery
Authors: Wang Chunsheng , Han Fudong 
Published: February 2020

Bulk-type all-solid-state lithium-ion batteries with nonflammable inorganic solid electrolyte are being considered as the ultimate solution for safe lithium-ion batteries. The current all-solid-state lithium-ion batteries suffer from low power density mainly due to strong kinetic limitation at the electrode/electrolyte interface. Here, we report a novel concept of a single-material all-solid-state lithium-ion battery, wherein a single Li10GeP2S12 serves as an electrolyte, an anode, and a cathode, to eliminate the highly resistive interface between the electrodes and electrolyte. The realization of the single-Li10GeP2S12 battery is based on the fact that the Li-S and Ge-S components in Li10GeP2S12 could act as the active centers for lithiation/delithiation as a cathode and an anode, respectively, when electronically-conductive carbon is mixed, while pure Li10GeP2S12 can be used as an electrolyte. This unique concept of a single-material lithium-ion battery can be extended to other solid-state battery systems, providing a new direction for high-power, high-energy, long-cycling solid-state batteries.
This work was mainly supported as part of Nanostructures for Electrical Energy Storage (NEES), an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Award Number DESC0001160.
Mixed Metal Phosphorous Oxides: Prospects for Secondary Lithium Based Batteries
Authors: Marschilok Amy C , Takeuchi Kenneth J , Takeuchi Esther S 
Published: February 2020

Cathode materials containing phosphate have met with success in lithium based batteries, with a notable example being lithium iron phosphate, LiFePO4. A recent focus for our research has been the investigation of bimetallic phosphates (MM’PxOy, where Mn+ = Ag, Cu), motivated by the desire to obtain the stability observed in phosphate based cathode materials and the opportunity for multiple electron transfers per formula unit due to the bimetallic composition of the materials.
Our initial electrochemical studies focused on Ag2VO2PO4 where the material provided a discharge capacity of 272 mAh/g and high current pulse capability. In-situ formation of silver nanoparticles upon initiation of reduction was accompanied by a 15,000 fold increase in cathode conductivity. Our paradigm of current enhancement via reduction displacement was in evidence.
An alternate composition Ag0.48VOPO4 material with lower silver content per formula unit shows a high operating voltage and characteristic multi-plateau voltage profile. Counter to Ag2VO2PO4, the reduction of Ag+ to Ag0 occurs later in the discharge process for Ag0.48VOPO4.
Based on the delayed reduction of silver, we hypothesized that the MVOPO4 material class may demonstrate improved reversibility relative to the AgVO2PO4 system. The MVOPO4 material is explored for secondary lithium based battery applications. The electrochemistry of the analogous silver and copper containing MVOPO4 materials will be compared and contrasted in this presentation. The inclusion of copper instead of silver in the structure is motivated by lower cost of copper versus silver and the accessibility of divalent Cu2+ which can provide 2 electron equivalents per metal center. However, the silver containing material offers the advantage of higher operating voltage. The electrochemistry will be summarized in the context of prior work other members of the MM’PxOy and MM’O material families.
Residual Stress in NiO-YSZ Composites and Its Relationship to Microstructure
Authors: Akaza Yoshiki , Syu Takaho , Iguchi Fumitada , Shimizu Makoto , Yugami Hiroo 
Published: February 2020

From the view point of mechanical reliability, the thermal expansion coefficient of anodes is adjusted to add proper amount of YSZ into NiO to prevent large thermal stress between anodes and electrolytes and keep the stress conditions as compressive from R.T. to operation temperatures for protect the electrolyte from tensile destruction and buckling destruction.

By contrast, Nickel oxide and YSZ, which thermal expansion coefficient is 14.1 and 10.8 [10-6 K-1], were contacted directly in anode. This suggests that large thermal strain and stress exist in anode at R.T. caused by the difference of large thermal shrinkage from sintering temperature e.g. 1400 oC to R.T. Moreover, these thermal strain and stress are probably strongly influenced by the difference of microstructure such as porosity, volumetric ratio, average diameter, uniformity because the introduction of them occurs at contact area between NiO and YSZ. However, stress conditions in anode, i.e. NiO-YSZ composites, were never studied in author’s knowledge.

In this study, we evaluated residual stress and strain in NiO-YSZ composites numerically and experimentally.

Numerical simulation was performed by Finite element method (FEM) using MARC. Residual stress and strain were evaluated by X-ray diffraction method. Both results suggested that stress conditions in NiO and YSZ are tensile and compressive, agreed with the expected states from the difference of thermal expansion coefficient. By contrast, average strain and stress were not so high. In the case of uniform NiO-YSZ (50:50 vol%), average stress is ca. 100 MPa and ca. -100 MPa (minus was compressive) for NiO and YSZ, respectively. These phenomena were explained by stress and strain relaxation because contact area between nickel oxide and YSZ was spatially distributed and introduced stress and strain reduced each other.

However, stress and strain distributions also suggested that stress and strain widely distributed and its FWHM, i.e. dispersion, was over 200 MPa. In addition, distribution analysis based on the simulation results of various uniformity NiO-YSZ revealed that the increment of ununiformity caused the increment of stress dispersion. These results indicated that bending moment introduced and stress concentration in the microstructure of NiO-YSZ composites causes these widely dispersion.
Evaluation of the Influence of Nickel Addition on LST-CGO Based Solid Oxide Fuel Cell Anodes Performance
Authors: Yurkiv Vitaliy , Constantin Guillaume , Gondolini Angela , Mercadelli Elisa , Sanson Alessandra , Dessemond Laurent , Costa Rémi 
Published: February 2020

Ni/YSZ composite materials have shown the tremendous success over past years for application as SOFC anodes. One of the biggest advantages of Ni/YSZ SOFC anode is its ability of direct utilization of various fuel types, i.e. H2/H2O, CO/CO2 and hydrocarbons. It is, however, well known that operation of those anodes upon various fuels could cause various types of cell degradation. Therefore, the replacement of Ni cermet with alternative ceramic materials is essential to develop long-term operating SOFC technology.
In the present contribution, we combine modeling and experimental study of electrochemical hydrogen oxidation at an alternative perovskite based mixed-conducting SOFC anode with and without an addition of nickel. Composite electrodes were produced by conventional wet ceramic processing (screen printing – spraying) and sintering on YSZ electrolytes (La0.1Sr0.9TiO3-α-Ce1-xGdxO2-α | YSZ) with different compositions and microstructure, and were electrochemically characterized using symmetrical button-cells configuration. An elementary kinetic model was developed and applied to explore the performance of LST based SOFC anode. A detailed multi-step heterogeneous chemical and electrochemical reaction mechanism was established taking into account transport of ions in all ionic phases, and gas transport in channel and porous media. It was found that heterogeneous chemistry at LST surface has capacitive behavior that alters the impedance spectra. In addition, surface charge-transfer reaction, which describes partial oxygen ionization, caused impedance feature and is rate-limiting at high temperature. However, if nickel is added to composite perovskite anodes the impact of LST surface chemistry is diminished leading to an improvement of cell performance.
Kinetic Monte Carlo Simulations of Solid Oxide Fuel Cell Cathode
Authors: LI Meiling , NI Meng 
Published: February 2020

The cathode microstructure is critical to development of high performance solid oxide fuel cells (SOFC). In this work, a 3D kinetic Monte Carlo (kMC) model is developed to study the microstructure evolution of SOFC composite cathodes during the sintering process. Conventional Lanthanum Strontium Manganite (LSM)-Yttria-stabilized Zirconia (YSZ) composites are used as model in the parametric simulations. The important sintering mechanisms are considered, including surface diffusion, grain boundary migration, vacancy creation, and annihilation. The triple-phase boundary (TPB) and effective conductivities of LSM and YSZ are computed during the sintering procedure. The effects of sintering temperature, initial particle size, and material composition on the cathode microstructure are studied and discussed. Optimal sintering conditions are recommended for high performance cathode design.
Oxygen Nonstoichiometry and Cathodic Property of Ce0.6Mn0.3Fe0.1O2-δ for High Temperature Steam Electrolysis Cell Using LaGaO3-Based Oxide Electrolyte
Authors: Hosoi Kohei , Sakai Takaaki , Ida Shintaro , Ishihara Tatsumi 
Published: February 2020

The reverse operation of SOFCs, so called solid oxide electrolysis cells (SOECs), can efficiently produce hydrogen from high temperature steam. Ni-based metal, which are widely used for anode of the conventional SOFCs, are also widely used for the cathode of SOECs due to its high catalytic activity and high electronic conductivity. However, Ni-based cathodes frequently showed low stability against oxidation resulting in deactivation under SOECs condition. As a result, Ni-based electrodes are easily aggregated and also delaminated from electrolyte. Therefore, it is essentially required to recycle a part of produced hydrogen to the Ni based electrodes for preventing the oxidation of Ni, however, this recycle of the part of hydrogen formed requires the complicated system and also decrease the electrolysis efficiency. In order to solve these problems, recently, oxide cathode have been attracting much attention for the cathod of SOECs instead of Ni-based metal. Since oxide cathode is stable in redox cycles, recycles of hydrogen is not required. However, oxide cathode have some disadvantages, for instance, low catalytic activity and also low electronic conductivity. In this study, Mn- and Fe-doped CeO2 (Ce0.6Mn0.3Fe0.1O2, CMF) was investigated as a new oxide cathode for SOECs. CMF is a mixed ionic and electronic conductor (MIEC), and has been reported as a potential anode catalyst for SOFCs. Although its electrical conductivity is lower than that of the typical perovskites oxide electrode materials (10-1 S/cm at 900 °C), its catalytic activity for electrode reaction was enough high when it is used in SOFCs.
Oxygen nonstoichiometry in this CMF was studied by thermogravimetry. It was found that higher oxidation state of Mn and Fe was observed resulting in hole conduction. The origin of this hole conduction was further studied by XPS measurement. On the other hand, in reducing atmosphere, because of the reduction of Ce, n-type semiconduction is observed. Therefore, oxygen nonstoichiometry of CMF is discussed in details from valence number of Ce, Mn, and Fe.
On the other hand, CMF cathode showed almost the same performance with that of Ni-SDC cathode in steam electrolysis and hydrogen evolution rate well obeys the Faraday’s law in temperature range of 900-700°C and stable electrolysis performance was observed. The XRD pattern and the SEM images of CMF cathode after the electrolysis measurement revealed that the CMF phase is stably remained and aggregation or delamination were hardly observed. These results suggest that CMF is highly promising as oxide cathode for SOECs
Influence of Substrate on Conductivity of Sr and Mg Doped Lanthanum Gallate Thin Film Electrolyte for Solid Oxide Fuel Cell
Authors: Dempoh Akishi , Endo Yoichi , Terai Takayuki , Suzuki Akihiro 
Published: February 2020

Solid oxide fuel cell (SOFC) consisting of ion conductive ceramics has various advantages such as the high generating efficiency, the utilization of hydrocarbon-containing fuel and the non-necessity of expensive rare metal catalyst. Yttria-stabilized Zirconia (YSZ) or Gadolinium-doped Ceria (GDC) are mainly used as the electrolyte for SOFC. Strontium- and Magnesium-doped Lanthanum Gallate (La0.9Sr0.1Ga0.8Mg0.2O3-δ, LSGM) has higher conductivity than YSZ, negligible electronic conduction and high chemical stability in a wide oxygen partial pressure range compared to GDC.
Recently, it was reported that YSZ and GDC thin films have different values of ion conductivity from those of the bulk. LSGM should have the similar phenomenon. The reason for this change of the conductivity is assumed to be the lattice strain in the thin film, the difference between the bulk resistivity and the grain boundary resistivity or space charge layers at homo- or hetero-junctions. However, the mechanism of the conductivity change of LSGM thin film from the bulk is not revealed.
In this study, the radio frequency magnetron sputtering, which is a reliable method for preparing thin film, was used for obtaining various thickness films on sapphire and quartz substrate. However, the deposited film was amorphous. To obtain the crystallized LSGM film, we investigated the influence of the annealing temperature. By proper post-annealing, crystallized LSGM film was obtained. We evaluated the crystallinity by X-ray diffraction, observed the microstructure with a scanning electron microscope and measured the conductivity by electrochemical impedance spectroscopy. In this paper, we report the effect on the electrical conductivity of the difference of thermal expansion co efficiency between LSGM thin film and the substrate.
Gas Concentration Measurements Using Photoacoustic Sensors for Industrial Solid Oxide Fuel Cell Process Control
Authors: Lengden Michael , Bauer Ralf , Johnstone Walter 
Published: February 2020

Tunable diode laser spectroscopy (TDLS) has proven to be a suitable optical sensing system for the measurement of methane and water vapour concentrations in Solid Oxide Fuel Cells (SOFCs). The unique advantages of TDLS include the ability to measure gases, including water vapour, in-situ and in real time, providing an ideal measurement system for large-scale fuel cell research and process control on an industrial scale. In this paper we present a technique similar to TDLS, known as photo-acoustic spectroscopy (PAS), which is capable of achieving much higher concentration measurement sensitivities with reduced sensor dimensions, enabling the possible integration of remotely controllable sensors within the SOFC enclosure. In order to achieve even greater sensor sensitivities, mid-infrared optical sources are required due to the higher probability of optical absorption. Here we present our recent work on miniaturised 3D printed PAS trace gas sensors (see figure), which includes the use of a mid-infrared quantum cascade laser as optical source. The 3D printed sensors have outside dimensions of approximately 25x15x10mm, with the optical interrogation coupled to the sensor through optical glass fibres or direct free-space coupling. The potential for PAS as a process control strategy for measuring SO2 concentration during the desulphurisation of a natural gas SOFC fuel source is presented. Results are also shown for PAS measurements of CH4 and CO2 concentrations in the mid-infrared and the near-infrared respectively, showing the capability of using PAS as a replacement for a GC in fuel cell research and process control.

Figure 1
Optimization of Tensile Strength Measurements on Glass-Ceramic Sealant Used for SOFC Stacks
Authors: Gross-Barsnick Sonja-Michaela , Babelot Carole , Federmann Dirk , Pabst Ulrich 
Published: February 2020

Glass-ceramic sealants are commonly used as joining materials for planar Solid Oxide Fuel Cell (SOFC) stacks. Several requirements need to be fulfilled by these materials: besides electrical insulation and adequate thermal expansion, a good adhesion on the ceramic and metallic components of a SOFC stack is necessary to form a gas-tight joint [1]. A key requirement is the mechanical strength of the sealant to maintain the integrity of the stacks under operation conditions [2]. Due to the lack of standardized methods, tensile tests were developed in-house. Preliminary measurements achieved reproducible results with extremely low tensile strength values for circular butt joints made of the iron-chromium alloy Crofer22APU and a composite sealant based on a glass matrix of the system of BaO-CaO-SiO2 reinforced with yttria-stabilized zirconia fibers [3, 4]. These results have been used for a qualitative ranking of different sealant materials.
The goal of our recent studies is to improve the characterization methods of mechanical strength in order to obtain quantitative results and to achieve the understanding needed to design more robust SOFC stacks. For this purpose, computer simulations using finite element analyses (FEA) have been performed. By modelling different joint configurations, it was possible to homogenize the stress distribution along the sealing layer and to optimize the geometries of the components. It was shown that bending of the metallic components as well as residual thermal stresses had a strong effect on the initial sample setup with thin cylinders. An optimized design for the tensile components allows a more uniform distribution of tensile stresses within the sample. Different joining conditions were investigated and the calculations were verified by experiments. Scanning electron microscopic analyses were carried out on cross sections and broken samples, which allow to evaluate the microstructure of the composite and its interfacial reactions. The mechanical strength values obtained by the improved characterization method represent a tenfold increase compared to the values published in [3].
[1] Gross et al., Fuel Cell Bulletin 9 (2006) 12-15
[2] Blum et al., J. Pow. Sources 196 (2011) 7175-7181
[3] Gross et al., J. Pow. Sources 196 (2011) 7338-7342
[4] Cela Greven et al., Fuel Cells 13, No.4 (2013) 565-57