bluuebunny/crossref_metadata_2025 huggingface dataset:
(Invited) New and Innovative Sensor Technologies for Aquacultural System in China
Authors: LI Daoliang , WANG Cong , Zhang Xiaoshuan
Published: February 2020

With the rapid development of aquaculture industry in China, the dimensions of aquaculture industry expands ceaselessly, at the same time the loss caused by the deterioration and pollution of aquaculture water quality becomes more and more serious, so it is urgent to turn the traditional extensive aquaculture mode into the modern aquaculture model with intensification, informatization and intellectualization. At present, lacking of monitoring on aquaculture water quality has become a bottleneck for the transformation of aquaculture industry. Therefore, our team mainly researches the intelligent solution and the implement method of water quality sensor( Do, pH, EC, temperature, NH4-N, turbidity, Chlorophyll etc.) based on electrochemical, optical, new materials in order to make the low cost water quality sensor precision improvably, maintain conveniently, service life increasing, to meet the aquaculture long-term monitoring demand, stimulate aquaculture high yield, high efficiency, safety, healthy production, for realizing the sustainable development of aquaculture lay the foundation. A mobile e-nose(multiple gas sensors) to provide the online monitoring and/or information record for those selected gas components, analysis the response characteristics parameters and mechanism, calibration method, gas signal processing and quality coupling, develop monitoring and traceability platform.
High-Throughput Atomic Layer Deposition for Surface Coating Materials of Lithium-Ion Batteries
Authors: Trevey James E , King David M , Dameron Arrelaine
Published: February 2020

Li-ion batteries have demonstrated a great capability for meeting the needs of an ever-growing market of mobile technology. However, as these applications become more demanding more energy and power will be required from rechargeable Li-ion batteries. To meet these needs there are many R&D efforts ongoing to design and generate new materials capable of higher performance. In contrast to this approach, higher performance electrode materials could be achieved through surface-engineering of existing materials. Atomic Layer Deposition (ALD), a vapor phase deposition technique used to apply Angstrom thick layers of material on the surface of powders and objects, has been demonstrated to enable higher voltage cycling, longer cycle life, and increased safety, as well as improvements to the manufacturing process of Li-ion batteries. Historically ALD has been regarded as slow and expensive, however Forge Nano has developed a method for applying ALD coatings onto materials at low cost and high volume. In this work, Forge Nano demonstrates the ability to utilize ALD to enable significant improvements to Li-ion battery performance as well as reduce costs to produce batteries at scale.
Lithium Ion Conductive Ceramic Fabric: Fabrication and Application
Authors: Gong Yunhui , Fu Kun , Dai Jiaqi , Hamann Tanner R. , Zhang Lei , Hitz Gregory T , Hu Liangbing , Wachsman Eric D.
Published: February 2020

Fibrous ceramic fabrics are commercially available products in different technical fields[1]. The fabrication technologies of fibrous ceramic fabrics are mainly categorized into direct spinning process and indirect template process. Here, we employed the template process to create the proof-of-concept lithium ion conductive fibrous ceramic fabrics, which generates unique structure with fine 3D scale distribution of continues lithium ion conductive phase, high surface area/volume ratio, low gravimetric density, multi-level porosity, certain strength and flexibility. The architectural advantages may allow the fibrous ceramic fabrics to be integrated to build components of solid state lithium metal batteries, such as flexible composite polymer electrolyte and rigid electrode skeleton. Because of the simplicity, rapidity and cost saving characteristics of template method, applicable transition from laboratory scale fabrication procedure to industry scale manufacturing is potentially achievable.

The generally sequential procedures of template method to prepare the fibrous ceramic fabric are: (1) Pretreating the replica template; (2) Impregnating the replica template with the precursor solution; (3) Converting the precursors into nano-sized ceramic oxide, pyrolysis of the replica template and sintering of the relic structure. Figure 1 presents the photo image of the fibrous ceramic fabrics composed of lithium ion conductive garnet phase. Different from the structure of conventional sintering of powder compact, the ceramic fabric retained the characteristic features of replica template, exhibiting complex geometric structure of woven pattern of continuous interlocked fibers and interlaced yarns. The fibrous garnet textile shows pronounced new characteristic features to tolerate certain flexural strength, geometrical tailoring and organic solvent erosion, which are distinct from the rigid appearance of typical sintered ceramic body. The chemical analysis confirmed cubic phase of the fibrous garnet fabric and homogenous distribution of the constituent elements.

Figure 1. Photo image of the fibrous ceramic fabric composed of lithium ion conductive garnet phase, which essentially retained the structural characteristics of the replica template.

Figure 1
Understanding the Effect of Solid Electrolyte Structure on Properties through 3D-Printing
Authors: McOwen Dennis W. , Gong Yunhui , Fu Zhezhen , Godbey Griffin L. , Gritton Jack E. , Zhang Lei , Wachsman Eric D.
Published: February 2020

Over the last decade there has been a sizeable effort within the battery community to improve upon the safety and performance of conventional Li-ion batteries to satisfy market demand. A large fraction of that effort has been devoted to solid-state garnet-type Li-conducting electrolytes, due to their inherent nonflammability, relatively high Li+ conductivity (~1 mS/cm), and stability to both lithium metal anodes and high voltage cathodes. Recently, improved materials properties and a paradigm shift in electrolyte microstructure have begun to make solid-state electrolytes competitive with liquid electrolyte counterparts in terms of performance [1,2]. Specifically, researchers have demonstrated 3 mA/cm2current density in Li|LLZ|Li symmetric cells and successfully cycled full cells using a porous-dense-porous multilayered LLZ solid electrolyte framework which dramatically reduces the bulk and interfacial impedance of the battery and increases the energy density by reducing excess electrolyte materials [2]. It is clear then that the solid electrolyte microstructure can have a substantial impact on cell electrochemical performance. However, the effect of the electrolyte microstructure on the cell properties has yet to be investigated, properties which are critical to ensuring high battery performance, long-lifetime of the battery and tolerance to abuse. An optimized solid electrolyte microstructure will need to balance electrochemical and mechanical properties for a marketable battery design.

In this work, we utilize 3D-printing to rapidly explore the relationship between solid electrolyte microstructure and resulting electrolyte and cell properties (e.g. mechanical strength). Specifically, we 3D-print a variety of different solid electrolyte geometries, including columns (Figure 1), grids, and stacked geometries using recently developed LLZ inks, and correlate the structure type and characteristics (e.g., aspect ratio) with properties of the electrolyte. First, we investigate the properties of the 3D-printed solid electrolyte itself, followed by a study including infiltration of electrode materials which is more representative of the final battery design. This study will help inform the best solid electrolyte microstructure, ensuring the structure of solid-state batteries will be suitable for a wide variety of real-world applications.

[1] J. van den Broek, S. Afyon, J. L. M. Rupp, Adv. Energy Mater., 2016, 6, 1600736.

[2] G. T. Hitz, D. W. McOwen, Y. Wen, Y. Gong, J. Dai, X. Han, T. R. Hamann, A. L. Ruth, P. C. Latorre, L. Hu, E. D. Wachsman, submitted.

Figure 1. 3D-printed LLZ columns.

Figure 1
Unrivaled Combination of Surface Area and Pore Volume in Micelle-Templated Carbon for Supercapacitor Energy Storage
Authors: Mitlin David
Published: February 2020

We created Immense Surface Area Carbons (ISACs) by a novel heat treatment that stabilized the micelle structure in a biological based precursor prior to high temperature combined activation – pyrolysis. While displaying the morphology akin to commercial activated carbon, ISACs contain an unparalleled combination of electrochemically active surface area and pore volume (up to 4051 m2 g-1, total pore volume 2.60 cm3 g-1, 76% small mesopores). The carbons also possess the benefit of being quite pure (combined O and N: 2.6 – 4.1 at.%), thus allowing for a capacitive response that is primarily EDLC. Tested at commercial mass loadings (~ 10 mg cm-2) ISACs demonstrate exceptional specific capacitance values throughout the entire relevant current density regime, with superior rate capability primarily due to the large fraction of mesopores. In the optimized ISAC, the specific capacitance (Cg) is 540 F g-1 at 0.2 A g-1, 409 F g-1 at 1 A g-1 and 226 F g-1 at a very high current density of 300 A g-1 (~0.15 second charge time). At intermediate and high currents such capacitance values have not been previously reported for any carbon. Tested with a stable 1.8 V window in a 1M Li2SO4 electrolyte, a symmetric supercapacitor cell yields a flat energy – power profile that is fully competitive with organic electrolyte systems: 29 Wh kg-1 at 442 W kg-1 and 17 Wh kg-1 at 3940 W kg-1. The cyclability of symmetric ISAC –cells is also exceptional due to the minimization of faradaic reactions on the carbon surface, with 80% capacitance retention at over 100,000 cycles in 1M Li2SO4 and 75,000 cycles in 6M KOH.
MCO-Coated Interconnects: Stack Testing and Results
Authors: Benhaddad Sofiane , He Hongpeng , Chen Chen , Steedman Dale
Published: February 2020

Coating development at Fuel Cell Energy is a continuous activity looking at optimizing chemistry, application process and features of the coating for longer life of the SOFC stack in high humidity level. Cathode interconnects surfaces are protected with manganese cobalt oxide (MCO) coatings to minimize chrome evaporation and poisoning of the fuel cell.

Protecting the surface of cathode interconnects becomes necessary to extend the SOFC life. Two different coatings have been studied at FCE. MCO was either deposited as a perovskite by dip coating or formed in situ during stack operation. A direct comparison of the two methods was studied after hundreds of hours in SOFC stack testing both in dry and humid air environment. The stacks were tested in normal conditions with dry air in cathode and also in air with additional humidity. A significant improvement in degradation rate and cell stability have been observed and achieved with those stacks.
Comparison of Pr-Based Cathodes for IT-SOFCs in the Ruddlesden-Popper Family
Authors: Bassat Jean-Marc , Vibhu Vaibhav , Nicollet Clément , Flura Aurélien , Fourcade Sébastien , Grenier Jean-Claude , Rougier Aline
Published: February 2020

The present study is focused on alternative oxygen electrodes for Intermediate Temperature Solid Oxide Fuel Cells (IT-SOFCs). Among the K2NiF4 type compounds, the nickelates Ln2NiO4+δ (Ln = La, Pr or Nd) have already shown their suitability as oxygen electrode due to their mixed ionic and electronic conductivity (i.e. MIEC properties). Pr2NiO4+δ showed the best electrochemical properties [1] at intermediate temperature among the three nickelates: R
p
= 0.15 Ω∙cm² at 600 °C for instance, for screen printed electrode. Interestingly, the ageing of the Pr2NiO4+δ//CGO//8YSZ symmetrical half cells during 1 month under air shows no significant change in the R
p value at i
dc = 0 condition, despite the decomposition of Pr2NiO4+δ into the third term of the R.P. series (Prn+1NinO3n+1), Pr4Ni3O10+δ, the perovskite PrNiO3-δ and Pr6O11. Such decomposition was observed after one month at different SOFC operating temperatures, namely 600, 700 and 800 °C under air [2]. Aiming at further understanding the relationship between the electrochemical behavior and the phase stability, the physico-chemical and electrochemical properties of Pr4Ni3O10+δ and PrNiO3-δwere thoroughly studied.

PrNiO3-δ is chemically very stable at operating temperatures up to one month while the electrochemical properties remain limited. The symmetrical half-cell with PrNiO3-δ electrode shows relatively high R
p value, for instance R
p = 0.9 Ω∙cm² at 600 °C, which is almost six times higher than the one of Pr2NiO4+δ [3]. On the other hand, Pr4Ni3O10+δ is a very promising material. In addition, Pr4Ni3O10+δ is highly chemically stable during long term up to 1 month under air at 600, 700 and 800 °C, contrarily to Pr2NiO4+δ [4]. Moreover, a single cell Pr4Ni3O10+δ//CGO//8YSZ//Ni-YSZ produces a very high power density of 1.60 W·cm-2 at 800 °C and 0.68 W·cm-2 at 700 °C. Hence, the electrochemical behaviors of Pr4Ni3O10+δ and Pr2NiO4+δ are similar, but Pr4Ni3O10+δis a more promising oxygen electrode since it is highly chemically stable.

Herein, the comparison of Pr-based cathodes, and more especially their chemical stability, conductivity and electrochemical properties will be presented and discussed in details.

References

[1] V. Vibhu, A. Rougier, C. Nicollet, A. Flura, J.-C. Grenier, J.-M. Bassat, Solid State Ionics, 278(2015) 32-37.

[2] V. Vibhu, J.-M. Bassat, A. Flura, C. Nicollet, J.-C. Grenier, A. Rougier, ECS Transaction, 68(2015) 825-835.

[3] V. Vibhu, J.-M. Bassat, A. Flura, C. Nicollet, N. Penin, J.-C. Grenier, A. Rougier, to be submitted in Journal of Solid State Electrochemistry, 2017.

[4] V. Vibhu, A. Rougier, C. Nicollet, A. Flura, S. Fourcade, N. Penin, J.-C. Grenier, J.-M. Bassat, Journal of Power Sources, 317 (2016) 184-193.
Systematic Lifetime Testing of Stacks in CO2 Electrolysis
Authors: Küngas Rainer , Blennow Peter , Heiredal-Clausen Thomas , Holt Tobias , Rass-Hansen Jeppe , Primdahl Søren
Published: February 2020

Haldor Topsoe is commercializing a system for on-site CO generation (eCOs®) based on solid oxide electrolysis technology. The standard system is capable of producing CO at 99.5% purity, but can also be customized to produce CO at 99.999% purity.

In this patented system, the electrochemical conversion of CO2 into CO is carried out in solid oxide stacks, each stack producing approximately 1.5 Nm3 CO/h. In contrast to SOFC operation, the performance of a stack operating in electrolysis mode is not exclusively determined by the area-specific resistance (ASR). While resistance determines the overall efficiency of the stack, other parameters, such as the purity of the produced gas, can be more critical in a commercial system.

A systematic approach to screening and evaluating stack and cell-level improvements is presented. Several long-term tests were carried out for 2000 hours at a reference operating point and then intentionally stopped to evaluate the extent of degradation in stacks and to qualify/disqualify different design modifications. The described approach was used to significantly improve stack robustness and lifetime in CO2 electrolysis.

Finally, some un-solved issues will be presented, in order to spur discussion on lifetime-limiting issues specific to electrolysis.
From in-Situ to in-Operando Evaluation of SOFC Cathodes for Enhanced ORR Activity and Durability
Authors: Wachsman Eric D. , Cohn Gil , Huang Yi-Lin , Pellegrinelli Christopher
Published: February 2020

To study the SOFC cathode oxygen reduction reaction (ORR) mechanism and the effects of ambient gas composition on ORR, we used in-situ
18O isotope exchange techniques to probe the exchange of H2O and CO2 with two of the most common SOFC cathode materials, (La0.8Sr0.2)0.95MnO3-x (LSM) and La0.6Sr0.4Co0.2Fe0.8O3-x (LSCF). A series of temperature programmed isotope exchange measurements were performed to comprehensively study the interaction of H2O and CO2 with the cathode surface as a function of temperature, oxygen partial pressure, and contaminant gas concentration. The experimental data are summarized in a Temperature-PO2 diagram to visualize the dominant reactions at each temperature and PO2 for the two cathode materials.

We further report on the development of a novel in-operando
18O isotope exchange technique by modifying our heterogeneous catalysis system for operation and measurement under electrochemical polarization. The system allows ORR investigations under real time, real life, operating conditions. We will present our studies on the effect of cathodic polarization on LSM and LSCF. The studies show the effects of operating voltage, temperature, and oxygen partial pressure on the oxygen exchange coefficient. We will also present our model for the understanding and analysis of the isotope oxygen exchange profiles under in-operando conditions.
SOFC Cathode Degradation Due to Salt Contamination
Authors: Thambiraj Nelson , Suciu Crina , Waernhus Ivar , Vik Arild , Hoffmann Alex C.
Published: February 2020

One of the fundamental impediments to the wide-spread commercialization of fuel cell technology is questions about the robustness and durability of this type of installation. In the course of a larger experimental program designed to answer these questions, specifically for operation in a marine environment, a series of tests were carried out to determine the sensitivity of SOFC cathodes to salt contamination in the gaseous feed stream. The salt content in the feed stream was varied by adding crystalline salt in the inlet piping, allowing it to sublimate at temperatures designed to give the desired salt concentration in the feed to the cathode. Both short-term and long-term degradation tests were performed, and in addition to characterizing the performance using the I-V curves, the microstructure of the cathodes were investigated using scanning electron microscopy before and after each run. The tests showed that there is degradation of the cathode due to the salt contamination, both in the short and the long term. While it was difficult to determine the reason for the short-term degradation, the long-term degradation was much more severe, and can be attributed to two effects: the salt appeared as crystals in the cathode microstructure and had a coarsening effect, and the presence of the salt gave rise to delamination of the cell at the cathode-electrolyte interface, something that was not observed under otherwise like operation conditions and -duration without salt contamination.
The Demosofc Project: Preliminary Results from an Industrial-Size Biogas-Fed Solid Oxide Fuel Cell
Authors: Gandiglio Marta , Lanzini Andrea , Santarelli Massimo , Hakala Tuomas , Rautanen Markus
Published: February 2020

The EU-funded DEMOSOFC project (www.demosofc.eu) aims to demonstrate the technical and economic feasibility of operating a 174 kWe SOFC in a wastewater treatment plant (WWTP). The fuel for the three SOFC modules (3x58 kWe) is biogas, which is available on-site from the anaerobic digestion of sludge collected from the treated wastewater. A heat-recovery loop allows to recover useful thermal energy from the hot SOFC exhaust gases (90-100 kWth). The recovered heat is transferred through a water loop to the sludge, which is pre-heated to 40-45 °C before feeding the digester. A full thermal recovery within the WWPT is thus achieved. Energy generated and recovered from the SOFCs will be consumed at the WWTP and will cover about 30% of the overall electricity demand and 50% of the yearly thermal demand.

The WWTP is located in Collegno, in the Turin premises (IT). The Collegno plant is serving around 180’000 Person Equivalent (P.E.), both residential and industrial users, and currently, exploits biogas for heating-only in a boiler.

The integrated biogas-SOFC plant includes three main units: 1) the biogas clean-up and compression section; 2) the three SOFC power modules, and 3) the heat recovery loop. The scope of the project is demonstrating the high-efficiency conversion of renewable fuel into electricity and heat.

The three SOFC modules are supplied by Convion (www.convion.fi), partner of the DEMOSOFC project. The first module has been shipped to Turin during April 2017, and the demonstration phase will last four years (2017-2020). The expected net electric efficiency of the SOFC is in the range 52-55%.

A special focus of the demonstration is the deep and reliable removal of harmful contaminants for the SOFC (mostly H2S and siloxanes) that are found in the raw biogas. In-line and real-time gas analysis are installed to monitor the removal efficiency of the biogas clean-up unit, which relies on solid sorbents (e.g., activated carbons).

The present work is related to the first on-field test of the SOFC units and the starting of the entire plant. After having completed mechanical and electrical connections, the first module has been fed by clean and compressed biogas on site produced and activated with a dedicated start-up procedure. The analysis is related to the SOFC operation, with a description of the starting procedure and preliminary performance results. The on-site produced and measured AC electric power is employed for the calculation of the net electrical efficiency; dedicated emissions measurements have been performed with simulated biogas at Convion facilities and will be replied on-site during the system operation.

Figure 1
Corrosion Analysis of Fuel Cell Metallic Materials at Elevated Temperature
Authors: Finsgar Matjaz
Published: February 2020

Corrosion of fuel cell metallic materials cannot be prevented, but there are ways to mitigate it. Environment in the fuel cells can be extremely corrosive and materials for fuel cells construction can deteriorate very fast if appropriate design is not employed [1].

In this work, different metallic materials for fuel cell construction will be tested under various conditions. Especially, an autoclave test will be designed to established corrosion monitoring of these materials at high temperature. Moreover, we will construct an autoclave corrosion cell to monitor corrosion electrochemically by various electrochemical techniques. After the corrosion tests a surface analytical techniques will be employed to reveal the composition of the corroded material (if corrosion will occur) by employing atomic force microscopy, x-ray photoelectron spectroscopy, Auger electron spectroscopy, and secondary ion mass spectrometry.

[1] Renato A. Antunes, Mara Cristina L. Oliveira, Gerhard Ett, Volkmar Ett, Corrosion of metal bipolar plates for PEM fuel cells: A review, International Journal of Hydrogen Energy, 35 (2010) 3632–3647.

[2] Jixin Chen, Jingwei Hu, James R. Waldecker, Comprehensive Model for Carbon Corrosion during Fuel Cell Start-Up, Journal of The Electrochemical Society, 162 (2015) F878-F889.
Development of Ammonia-Fueled SOFC
Authors: Satomi Erika , Iwai Hiroyuki , Suzuki Shinsuke , Koide Takeshi , Takahashi Yosuke , Eguchi Koichi
Published: February 2020

Ammonia has been studied as an energy carrier because of carbon-free and high hydrogen capacity.

We have investigated performance of ammonia-fueled SOFC (Solid Oxide Fuel Cell) to study the possibility of ammonia as an energy carrier.

In SOFC generation system, stack, which is made by cells, sealing glass and other materials, are main parts. These parts need ammonia resistance at 700-800 degree. So we developed sealing glass which has an ammonia resistance at 700-800 degree and fabricated 200W class stack.

Ammonia was directly supplied to the anode chamber. The performance of ammonia-fueled SOFC was same as well as that of hydrogen-fueled SOFC.
A Novel Method to Fabricate Inert Substrate-Supported Microtubular Solid Oxide Fuel Cells by Selective Leaching
Authors: Hedayat Nader , Panthi Dhruba , Du Yanhai
Published: February 2020

Microtubular solid oxide fuel cells (mT-SOFCs) are promising electrochemical energy conversion devices due to their high volumetric power density, capability of bearing high thermal stresses, and rapid start up. The inert substrate-supported mT-SOFCs have an additional advantage of high reduction–oxidation (redox) cycling stability. In this study, a novel method is suggested to fabricate inert substrate-supported mT-SOFC by leaching out the nickel from an anode supported mT-SOFC that has an anode functional layer. The anode supported mT-SOFCs were prepared by a sequential dip coating and co-firing process. The manufactured inert substrate-supported mT-SOFCs possess the configuration of yttria-stabilized zirconia (YSZ) support/Ni–Scandia stabilized zirconedia (ScSZ) anode/ScSZ electrolyte/strontium-doped lanthanum manganite (LSM)-ScSZ cathode/LSM cathode current collector. Selective leaching of the nickel from the Ni-YSZ composite was used in conjunction with the burn out of microcrystalline cellulose pore-former for the proper tuning of porosity and facilitating the gas diffusion through the inert support. The effectiveness of this approach on enhancing the fuel cell performance will be discussed.

Figure 1
Properties of Gadolinium-doped Ceria (GDC) Films Deposited by Reactive Magnetron Sputtering Processes
Authors: Hernandez Londono Carlos , Combemale Lionel , Gao Fei , Billard Alain , Briois Pascal
Published: February 2020

Reactive magnetron sputtering deposition technique was used for formation of gadolinium doped ceria oxide (GDC) thin films 5- 10µm. Material characteristics and chemical compositions of GDC films were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and 3D profilometry. In order to optimize the deposition of GDC to obtain high electrochemical performance of the cells, the influence of film thickness is studied. The GDC thin films were deposited on porous NiO–GDC (nickel oxide–Gadolinium stabilized ceria), the pre-sintered anode green tape were coated with a GDC electrolyte film by reactive magnetron sputtering using PEM (Plasma Emission Monitoring). An Alcatel SCM650 sputtering chamber was used for synthesizing the dense GDC layers. A Ce-Gd metallic target (90-10% at) was powered by a pinnacle + pulsed current generator from Advanced Energy. The structural, microstructural and morphological features of the half-cells were determined by XRD, SEM and 3D profilometry as deposited and after different annealing treatments. The obtained half-cell, 28 mm of diameter, anode supported solid oxide fuel cell, the porous and density of Ni-GDC10 composite anodes have been elaborated by tape casting method. The chosen ceramic powders in suspension were prepared with the mass ratio of 65:35 for NiO to GDC10. The microstructural morphological /porosity/surface features of the half-cell were analyzed by Scanning Electron Microscopy (SEM), XRD and 3D profilometry before and after different annealing treatment. Pycnometry and porosimetry techniques were primarily used to determine pore size and pore volume by equation Washburn and Ideal gas law-method. Finally, the EIS (Electrochemical Impedance Spectroscopy) measurements were done on Ni-GDC10/GDC10 half-cells under 60 sccm nitrogen by the means of a Solartron SI 1260 impedance / gain analyser from 20 MHz to 0.1 Hz with 11 points per decade.
Effect of Carbon-Neutral Fuel Fed Solid Oxide Fuel Cell System on CO2 Emission Reduction
Authors: Tachikawa Yuya , Matsuzaki Yoshio , Kawabata Yasuharu , Sugahara Mariko , Somekawa Takaaki , Taniguchi Shunsuke , Sasaki Kazunari
Published: February 2020

Solid oxide fuel cell (SOFC) system shows a significant potential to achieve carbon emission reduction and highly efficient power generation compared with typical power generation systems. The Paris Agreement requires decreasing greenhouse gas emissions for preventing tragic climate change. Hence SOFC conventional fuels are hydrocarbons (CxHy), the hydrocarbon would generate carbon dioxide (CO2) after fuel oxidation.

Ammonia and biomass-derived fuel are carbon-neutral fuels. Therefore, there are no carbon emissions after power generation. While those fuel supplied SOFC systems have an advantage without CO2 emissions, the influence on the system performance should be quantified to compare with conventional fuel supplied SOFCs. In this study, 100kW scale SOFC system model shown in Fig.1 (a) was evaluated in heat and mass balance analysis to consider the effect of supplied fuel on the SOFC system performance. A protonic ceramic electrolyte application was also evaluated to increase its electrical efficiency. The carbon-neutral fuel fed protonic ceramic fuel cells (PCFCs) had an advantage to enhance the electrical efficiencies compared with the same fuel fed typical SOFCs shown in Fig.1 (b). As highly efficient power generation system without CO2 emissions, the effects of carbon-neutral fuels on the electrical efficiency and the emission reduction were investigated by the process simulation of total fuel cell system.

Figure 1
Carbon Tolerant Double Site Doped Perovskite Cathodes for High-Temperature Electrolysis Cells
Authors: Hu Boxun , Aphale Ashish N , Liang Chiying , Heo Su Jeong , Uddin Md Aman , Singh Prabhakar
Published: February 2020

Solid oxide electrolysis cells (SOECs) of configuration La0.85Sr0.15Cr0.2Co0.1Ti0.7O3-δ (LSCCT)//ScSZ//GDC-LSM have been fabricated and electrochemically tested for the electrolysis of CO2 and H2O. Performance of the cell has been compared with standard Ni-SDC/ScSZ/GDC-LSM cell. EIS results show that LSCCT//ScSZ//GDC-LSM cell has higher non-ohmic resistance than the standard cell in 5% H2-CO2 containing environment. However, Cu impregnation of the LSCCT cathode using wet impregnation technique results in significant reduction in the non-ohmic resistance. Decrease in the thickness of the LSCCT cathode also reduces both ohmic and non-ohmic resistances. With the applied electrolysis voltage of 1.6 V at an operating temperature of 800 °C, the cell exhibited stable performance in 5% H2O/CO2 for more than 50 h with the electrolysis current density of 0.45 A.cm-2. Post-tested LSCCT cathode showed no carbon deposition whereas standard cell showed filamentary carbon formation and pulverization. Observations pertaining to surface (gas – electrode) and interface (electrode – electrolyte) will be presented.
Reversible Protonic Ceramic Electrochemical Cells for Power Generation and Green Fuel Production
Authors: Duan Chuancheng , Sullivan Neal P , Braun Robert J. , Kee Robert J. , Ding Hanping , Le Long Quoc , Dubois Alexis , O'Hayre Ryan
Published: February 2020

A Reversible Protonic Ceramic Electrochemical Cell (RPCEC) is a device based on proton-conducting ceramics that can operate in both fuel cell and electrolysis cell modes. Compared to reversible electrochemical devices based on oxygen-ion conducting ceramics, RPCECs offer several potential advantages including lower temperature operation, improved coking resistance, and broad fuel flexibility. In fuel cell mode, RPCECs can efficiently convert the chemical energy contained within a wide variety of fuels (including hydrogen, various hydrocarbons, methanol, ethanol and ammonia) to electricity at intermediate temperatures (300 °C-600 °C). In electrolysis mode, RPCECs can operate with applied power from a renewable source (e.g. solar) to produce a number of versatile chemical fuels including hydrogen (via water electrolysis), ammonia (via solid-state electrochemical ammonia synthesis), and even certain hydrocarbon and/or liquid fuels. In this work, we will overview our progress towards fuel-flexible, intermediate-temperature RPCEC devices with promising performance, stability, and efficiency in both electricity-production and fuel-production modes.
Effect of Microstructure on Ionic Conduction of Composite Electrolytes Consisting of Doped Ceria and Carbonates
Authors: Fung Kuan-Zong , Ni Chung-Ta , Tsai Shu-Yi , Tang Jhih Yu
Published: February 2020

Composite Electrolytes consisting of oxygen ion conductors and carbonates have received great attention for high temperature fuel cell application. For example, enhanced conduction was observed when the oxygen ion conductor, doped ceria was directly mixed with Li/K carbonates. The electrical conduction of composite electrolyte was contributed by the migration of oxygen ions in solid state and carbonate ions in liquid state. It was observed that the two-phase electrolytes exhibit coionic (O=/H+) conductors during fuel cell operation under the H2/ air atmosphere. It is believed that highly mobile ions at the interface between doped ceria and carbonates may contribute to the high conductivity of the composite electrolyte. In other words, the super-ionic phase might exist at the interface between doped ceria and carbonates, where the defect concentrations are high. Thus, the electrical conduction of composite electrolytes with various types of microstructures were evaluated at temperatures ranging from 300℃to 700℃. For powder mixture, the composite samples were prepared by direct mixing of doped ceria and carbonate powders. For infiltrated composite, the carbonates were infiltrated into porous ceria substrates at 600℃. SEM, XRD, and Electrochemical Impedance Spectroscopy were employed to conduct microstructural, structural and impedance analyses. The electrical conduction behavior of composite electrolytes will be rationalized based on the pore size, pore distribution and interface area.
Modified Butler-Volmer Type Model Which Accounts for Triple and Double Phase Boundary Reaction Pathways
Authors: Mason Jerry Hunter , Celik Ismail Bektas , Abernathy Harry , Hackett Gregory A
Published: February 2020

Modeling electrochemical reactions in solid oxide fuel cells (SOFCs) is a difficult and contentious topic. Recently, detailed reduced order reaction models have been presented which take into account more detailed physics than the widely used Butler-Volmer (BV) type equations. For this study, a reduced order oxygen reduction reaction (ORR) model previously developed specifically for yttria stabilized zirconia (YSZ)/lanthanum strontium manganite (LSM) cathodes is considered. The most prominent electrochemical pathways have been identified as the triple phase boundary (YSZ/LSM/pore) or surface pathway and the double phase boundary (YSZ/LSM) or bulk pathway. The ORR model considered predicts a competition between which pathway is most prominent depending on local overpotential, reactions rates and species concentrations (particularly oxygen partial pressure). However, this model and those similar to it require separate species transport equations to be solved for numerous species and surface coverages which result in a very stiff system of non-linear equations. Such a system becomes cumbersome numerically especially when trying to perform complex simulations such as impedance analyses, in comparison to BV type models. On the other hand, the traditional BV type equations are not able to distinguish between the reactions at the triple phase boundaries (TPBs) and the double phase boundaries (DPBs). In the study, the relationships between the total current, over potential, oxygen partial pressure, temperature and particularly TPB and DPB are explored based on the previously developed ORR model and experimental data from literature. Using these relationships, a new model is proposed for calculating the exchange current density as part of a BV type model which takes into account both TPB and DPB pathways as well as oxygen partial pressure. The model is then applied to situations of different TPB and DPB densities and reaction rates (exchange current densities) and compared to similar studies using the ORR model in order to verify that the model correctly handles the relationship between the two current pathways. It was found that the proposed BV model produces results comparable to the ORR model all with computational time for similar analyses being approximately 10,000 times shorter (due to decreased stiffness). The results obtained from the BV model are encouraging and indicate that a similar model can be developed for the anode side and different cathode materials, thus resulting in a robust modeling and analysis tool for SOFCs. This would amount to huge time and cost savings especially for simulations of large planar cells and cell stacks.
Mechanical Properties of SOFC Anode Support Materials at Operating Conditions
Authors: Stanley Patrick , Hays Thomas H , Langdo Thomas , Wachsman Eric D.
Published: February 2020

The mechanical properties of solid-oxide fuel cells (SOFCs) and the materials they are fabricated from play an important role in manufacturability, durability and lifetime of the devices. Functioning cells must maintain a gas-tight seal though the cell, with no cracks or pores from anode or cathode, through a range of temperatures and oxygen partial pressures. The cell must be able to withstand intrinsic stresses in addition to those introduced by the stacking and sealing of the cells. It is known that the environmental conditions can affect the mechanical properties of materials. It has been shown that point defect concentration and temperature change the elastic modulus and strength of fluorite-structured oxides, but these tests were done using quenched samples or at high temperature in air, not at operating conditions.

In this work the flexural modulus and strength of SOFC support materials are investigated under varying oxygen partial pressures at elevated temperatures, under the same conditions SOFCs experience during operation. This is achieved by using a three-point bend fixture on a universal testing machine, with a chamber and furnace to control the environmental conditions. From this information, relationships are built relating materials’ modulus and strength to the defect concentrations and temperatures that it would experience during operation.
Physico-Chemical Characterisation of Ce0.7Sr0.3Fe0.9Ir0.04Co0.06O3-
δ (CSFIC) Cathode Material for Application in Low Temperature SOFCs
Authors: Njoku Chima Benjamin , Omondi B O , Ndungu Patrick
Published: February 2020

In this study, Sol-gel technique was used to synthesize the cathode CSFIC perovskite material and it was then tested for its characteristic application in solid oxide fuel cell. The textural properties were tested using Raman spectroscopy and Fourier transform infrared spectroscopy. The crystal structure was tested using X-ray diffraction and the morphology and microstructure was examined using scanning electron microscopy and high resolution transmission electron microscopy. The power density and current density were measured with a Nuvant TM potentiostat and galvanostat from Fiaxell SOFC technologies connected to the cell setup. These properties were tested for their potential application in low temperature solid oxide fuel cells from 300 to 500 °C. It exhibited a current density of 772.35 mA/cm2, a power density of 455.49 mW/cm2 and an area specific resistance (ASR) of 0.349 Ω cm2.
Cathode Functionalization Via Atomic Layer Deposition for Solid Oxide Fuel Cells
Authors: Karimaghaloo Alireza , Johnson Sean , Huang Oscar , Macedo Andrade Angela , Lee Min Hwan
Published: February 2020

Crucial ­­processes in solid oxide fuel cell (SOFC) such as ionic transport and electrode reactions are thermally-activated processes and their kinetics are strongly dependent on the temperature. Despite intense recent efforts to reduce its operating temperature to address durability, cost and applicability issues, it is still an ongoing challenge to deal with the resulting sluggish kinetics and power losses at lower temperatures. On the other hand, while catalysts with higher surface area are preferred for maximized catalysis per mass and volume, these high-surface area catalysts are prone to agglomeration sacrificing its overall catalytic activity during operation. In this talk, we will present a couple of examples how these issues have been successfully addressed by the use of atomic layer deposition (ALD), which has emerged as an important deposition technique for various applications due to its unique atomic-scale deposition capability in a highly controllable fashion at a temperature significantly lower than conventional chemical vapor deposition techniques. We will present several examples of enhancements in cathode performance and/or durability enabled by an ultrathin coating of Y-doped zirconia or ceria (i.e. YSZ or YDC) on different nano-porous cathode materials including Pt, La(Ni,Fe)O3 and (La,Sr)(Co,Fe)O3. In addition, we will report mechanism studies mainly performed via electrochemical impedance spectroscopy and electron microscopy focusing on the shift of the rate-determining step by the ultrathin overcoat.

Acknowledgement: The authors gratefully acknowledge Nissan Motor Co. Ltd. and NASA MIRO Program (Grant No. NNX15AQ01A) for their financial support.
Fabrication of Metal Organic Framework Flexible All Solid State Supercapacitors By Electrophoretic Deposition
Authors: Amir Fatima Z. , Peck Jason , Hanna James M
Published: February 2020

Two-dimensional (2D) materials exhibit remarkable properties that suggest many possibilities for electronic applications. Metal organic frameworks (MOFs) are 2D nanosheets materials, which are good candidates for applications in various electrochemical applications such as fuel cells, batteries, and supercapacitors. Herein we report the fabrication of Ni3(2,3,6,7,10,11-hexaaminotriphenylene)2 (Ni3(HITP)2) flexible all solid-state supercapacitors by electrophoretic deposition (EPD). The Ni3(HITP)2 films were electrophoretically deposited in a layer-by-layer fashion onto targeted substrates. The electrodes’ surface morphology characterized by SEM shows a porous surface, and a honeycomb morphology known for improving the capacitive performance. TEM pictures confirmed the ultrathin two-dimensional structure of the (Ni3 (HITP)2) electrodes. The electrochemical capacitive performance of the obtained symmetric Ni3(HITP)2 supercapacitor has been characterized using cyclic voltammetry measurements and galvanostatic charge-discharge tests. This work demonstrates an exciting potential of EPD for the fabrication of high performance MOFs for flexible solid state energy storage systems.
Probing the Nanoscale Heterogeneity of SEI on Silicon Anode Using Tip Enhanced Raman Spectroscopy (TERS)
Authors: Yang Guang , Voylov Dmitry N. , Naguib Michael , Ruther Rose E. , Veith Gabriel M. , Lavrik Nickolay V. , Bocharova Vera , Sokolov Alexei P. , Nanda Jagjit
Published: February 2020

The composition, morphology and thickness of solid electrolyte interphase (SEI) on silicon anodes are dictated by multiple factors, ranging from the chemistry of silicon surfaces, electrolyte solution structure and chemical passivation on Si surface. In addition, the SEI constantly evolves, as it is electrochemically lithiated (delithiated) due to the enormous volume changes. SEI on silicon typically is reported to be in the range of tens of nanometers and can be compositionally heterogeneous. Normal vibrational spectroscopy techniques such as confocal micro-Raman and FT-IR are useful, but they only provide chemical information at a relatively bulk scale, typically in micron-distance from the solid surface. This makes it extremely hard for getting information from the real SEI, which can be only on the order of 10 nm. Tip Enhanced Raman Spectroscopy (TERS) combines surface plasmon-enhanced Raman spectroscopy with atomic force microscopy, capable of providing the chemical vibrational information and topography of the sample in the nanometer spatial resolution simultaneously. In this report we demonstrate the first TERS study of SEI on cycled amorphous silicon. Amorphous silicon anode (20 nm in thickness on copper current collector) was cycled in a commercial lithium-ion battery electrolyte (1M LiPF6 in EC:DEC, 1:1 vol). TERS analysis on cycled amorphous silicon sample indicates that the nanometer scale SEI “islands” are unevenly distributed on the Si anode surface. Even for the same SEI “island”, the composition is different from point to point with inter-point distance smaller than 2 nm.

Acknowledgment

This work is funded by Assistant Secretary for Energy Efficiency and Renewable Energy, Office of Vehicle Technologies of the U.S. Department of Energy
Chemical Lithiation of Pre-Encapsulated Sulfur Using Lithium Triethylborohydride for Lithium Sulfur Batteries
Authors: Glaser Rebecca , Johnson Billy , Yushin Gleb , Sanghadasa Mohan
Published: February 2020

As a promising anode material due to its high theoretical capacity (1675 mAh/g) and energy density (2600 Wh/kg), lithium sulfide has been the focus of significant research.1 In addition to being composed of non-toxic, environmentally-friendly elements, lithium-sulfur batteries offer light weight with low cost. Significant drawbacks of lithium sulfur batteries for commercial use are the short cycle life due to the polysulfide shuttle mechanism and the difficult processing required for their air-sensitivity. One approach to mitigating the shuttle mechanism is carbon encapsulation, which both physically constrains the active material and provides electrical conductivity to the insulating sulfur and lithium sulfide. Creating a fully encapsulating conformal coating of Li2S is challenging, but can be circumvented by first infiltrating sulfur into carbon and lithiating to form Li2S inside pre-made carbon particles. Melt-infiltration of sulfur for sulfur-based anodes has been extensively studied; however, anodes containing Li are more advantageous both from a safety perspective and because space is already made for the Li, avoiding troublesome volume expansion issues. While chemically lithiatiated sulfur and its encapsulation have been studied,2 lithiation of pre-encapsulated sulfur is a unique processing method.

In this research, lithium triethylborohydride is investigated as a lithiating agent for sulfur previously melt-infiltrated into a range of nano- and meso-scale carbons. Tuning the reaction temperature, precursor ratio, and amount of solvent gives control over Li2S:C ratio with the aim of keeping the Li2S fully inside the carbon particles. Li2S-C composites have been fabricated and are being evaluated for their electrochemical performance, size and location of Li2S particles, and adequacy to protect against polysulfide dissolution. Optimization of CVD coatings as an additional protection is evaluated. In contrast to traditional methods of encapsulating lithium sulfide, this approach produces higher mass loadings with facile solution processing. In the future, additional lithiating agents, such as N-butyl lithium, and lithium aluminum hydride, will be examined for their efficacy.

(1) Wu, F.; Lee, J. T.; Fan, F.; Nitta, N.; Kim, H.; Zhu, T.; Yushin, G. Adv. Mater.
2015, 27 (37), 5579–5586.

(2) Nan, C.; Lin, Z.; Liao, H.; Song, M. K.; Li, Y.; Cairns, E. J. J. Am. Chem. Soc.
2014, 136 (12), 4659–4663.