bluuebunny/crossref_metadata_2025 huggingface dataset:
In Operando Characterization of Cutting Edge Fuel Cells Catalysts Using X-Ray Absorption Spectroscopy: Capabilities of the XAFS Beamline at Synchrotron Elettra (Trieste, Italy)
Authors: Pollastri Simone , Aquilanti Giuliana , Fiala Roman , Olivi Luca , Mysliveček Josef , Matolin Vladimir
Published: February 2020

In a world with a growing population, the demand for energy is rising as never before and we are aware that fossil fuels are not the solution due to their enormous environmental costs (such as the effects of climate change) that can only be thwarted in a low-carbon society.

In this context, the role of batteries and fuel cells in everyday life is undeniable, and tremendous efforts are made to optimize their performances. The knowledge of the relationship between the electrochemical processes and the chemical and morphological changes is a necessary step for such optimization.

An inevitable ingredient of this research are the experiments conducted in operando conditions, very useful for the study of the local chemical environment of electrode materials (electrodes, electrolytes and catalysts). In fact, in operando experiments, the collected data provide an accurate representation of the reaction behavior found under normal operating conditions and with realistic gaseous or liquid environments. Moreover, experiments conducted with this method allow to prevent several drawbacks due to the sample transfer needed for typical ex situ measurements. Alteration of air or moisture sensitive species is avoided, as well as the occurrence of relaxation reactions which might show up when the electrical circuit is open, inducing a transformation of the initial cycled material. The whole study can be performed on a single test cell suppressing the effects of uncontrolled differences in a set of cells which are needed for a stepwise ex situ study of the electrochemical mechanism.

X-ray absorption spectroscopy is a synchrotron radiation based technique that is able to provide information on both local structure and electronic properties in a chemically selective manner. It can be used to characterize the dynamic processes that govern the electrochemical reactions, and to shed light on the redox chemistry and changes in structure to design efficient materials with improved properties. The XAFS beamline at Elettra is dedicated to X-ray absorption spectroscopy and can operate in a large energy range (from 2.4 to 25 keV). Although conceived to be general purpose, recently a lot of research has concerned the operando study of state of the art fuel cells and batteries.

In this presentation, the XAFS beamline at synchrotron Elettra will be described together with the experiments conducted in operando conditions on proton-exchange membrane fuel cells (PEMFCs) in the context of the CERIC Grant Research proposal “CEROP”, aimed at deciphering single-atom catalysis in Pt/ceria systems. Moreover, improvements recently implemented at the XAFS beamline to perform this type of measurements will be shown.
A Method to Fabricate Nanocrystals of Metal Oxides on Carbon Nanotube Surfaces
Authors: Yang Jun , Cheng Junfang , Nakashima Naotoshi
Published: February 2020

Many attention has been focused on the development of non-precious metal-based electrocatalysts for fuel cells and batteries with high performance, durablity, and scalability for the next-generation eco-friendly energy society[1-3] in order to reduce the cost of the catalysts.

In this meeting, we present a method to fabricate nanocrystals of metal oxides on carbon nanotube surfaces, which was carried out based on the recent finding that pristine multi-walled carbon nanotube/iron phthalocyanine hybrids with a well-defined nanostructure showed an excellent efficiency and durability for oxygen reduction reaction[2], as well as decorating unoxidized-carbon nanotubes with homogeneous Ni-Co spinel (and related) nanocrystals showed a superior performance for oxygen evolution/reduction reactions[3].

References

[1] T. Fujigaya, N. Nakashima, Adv. Mater., 2013, 25, 1666-1681.

[2] J. Yang, F. Toshimitsu, T. Fujigaya, N. Nakashima, J. Mater. Chem. A, 2017, 5, 1184-1191.

[3] J. Yang, T. Fujigaya, N. Nakashima, Sci. Rep., 2017, 7, 45384.
Preparation and Characterizations of Anion Conducting Ionomer Binder Solutions for Solid Alkaline Fuel Cells
Authors: Han Soo-Jin , Kang Moon-Sung , Park Jin-Soo
Published: February 2020

Compared to fuel cells using proton exchangeable polymers, the direction of ion movement in the fuel cells using anion conducting polymer membranes shown in Figure 1 is opposite which is from cathode to anode. The hydroxyl ion movement mitigates overpotential for oxygen reduction reaction as well as water flooding at cathode. In addition, they overcome the disadvantages of alkaline fuel cells such as formation of carbonate precipitates, leakage of liquid KOH electrolyte, system complexity and so on by using solid electrolytes. Anion conducting ionomers are the polymers where anion exchangeable fixed groups, e.g., quaternary ammonium groups, are covalently attached to main backbones. It conducts the selective movement of anions which is allowed to be transported inside free volume of wet polymers. Much efforts are devoted to the development of anion conducting membranes as electrolytes of the fuel cell, but few researches on ionomer binder solutions for preparation of electrodes of membrane-electrode assemblies were carried out due to the technical difficulty in dispersing the polymers in various solvent systems. In this study, poly(phenylene oxide) (PPO) were brominated and in-situ quaternized by trimethyl ammonium during membrane casting. Once it was cast, it was hardly dispersed in any solvent system. Thus, the polymer was frozen by aqueous nitrogen and was ground by a blade-type grinder. Upon grinding time, the final forms were powders with different size of particle. The powder was used to prepare ionomer binder solutions, and the solutions (or dispersions) were characterized in terms of ion conductivity, ion exchange capacity, FT-IR, dynamic light scattering. In addition, the performance of membrane-electrode assemblies with the content of the ionomer with respect to I-V polarization, cyclic voltammetry, and impedance.

Acknowledgment

This work was supported by the New and Renewable Energy of the Korea Institute of Energy Technology Evaluation and Planning(KETEP) granted financial resource from the Ministry of Trade, Industry & Energy, Republic of Korea (No. 20153030031720).
Electrochemical Characterization of Green Synthesis of NiO NPs Using Manihot Esculenta
Crantz for Alkaline Fuel Cell
Authors: Guzman Jorge A. Avila , García M.a. Lucio , Escobar Beatriz , Araujo Jesus A. , Ruiz Durcy V.
Published: February 2020

In actuality, the energetic demand is increase however the research of new sources of energies is beginning to satisfice the energy’s needs. The cleaning energies ´re alternative to solve this demand energetic, to get energy without involving the burning of fossil fuels. One of the options to remedy this demand is the use of alkaline type fuel cells, because present a good energy efficient. A limitation for the application of this technology lies in the catalytic supports. Frequently are designed with platinum, but this increases the cost of production. For this technology are very important because on this catalytic supports the reactions of oxide-reduction is where it take place and allow the generation of energy one alternative to remedy is the use of nanoparticles on the catalytic supports. On the other way, the green chemistry offers an alternative for the development of nanoparticles (NPs), these NPs can be synthesized from plant extracts, reducing the cost and obtaining processes, and friendly to environment. Nickel (Ni) is one of the most abundant metals in the earth’s crust and easily accessible in its oxide form, its easy disposition and its electroconductive properties makes it a good candidate to develop NPs and can to be supported on the electrodes. Green synthesis of nickel oxide nanoparticles (NiONPs) is a ecofrendly route and low cost. The use of extracts obtained from Manihot Esculenta (M. Esculenta) as a reducing agent for synthesis of NiONPs. Obtained a material with electrocatalytic behaviour and the low cost. Allowing to apply this technology in a future near as an energy alternative. The transmission electron microscope allowed to knew the size of the NiONPs, varying between 7.5 nm and 8.3 nm. The electrochemical proprieties of NiONPs were investigate using cyclic voltammetry and electrochemical impedance spectroscopy.
Nickel-Modified Co-Mo Electrocatalysts for Ethanol Oxidation in Alkaline Medium
Authors: Chaitree Wasu , Kalu Egwu Eric
Published: February 2020

As-deposited Co-Ni-Mo electrocatlyst on carbon support was investigated for the ethanol oxidation, and its activity was compared to that of Ni, Co, and bimetallic Co-Mo electrocatalysts. All electrocatalysts were prepared by electroless deposition method on carbon substrate support (CCS) made active for electroless deposition with Pd-ink. For ternary eletrocatalysts, the effects of electroless deposition time, reaction temperature (30-60°C) were studied. The result showed that CoNiMo/CCS was highly active in alkaline ethanol solution (0.5M NaOH+1 M EtOH) for ethanol oxidation. Furthermore, the reaction performances for all electrodes were investigated using cyclic voltammetry (CV). The result shows that Ni and Co electrodes showed not only oxidation peaks but also reduction peaks, which were typical behaviors for ethanol oxidation. For Co-Mo and Co-Ni-Mo electrodes provided the similar CV patterns. However, the current densities for tri-metallic electrode were higher than those from Co-Mo electrode. This suggests that the nickel has helped increase the reaction activity. Furthermore, the oxidation kinetics parameters, activation energy (Ea) and rate constant (k) were determined form CV, which were tested at different temperature and ethanol concentrations. Overall, this study provides a promising novel and effective non-noble Co-Ni-Mo electrocatalyst with an onset potential of -0.7 V (vs. Ag/AgCl).
(Invited) Addressing Fundamental Materials Challenges in Electrochemical Water Splitting Technologies for Sustainable Hydrogen Production
Authors: Miller Eric L. , Randolph Katie , Peterson David , Rustagi Neha , Vickers James W , Lyubovsky Maxim , Cierpik-Gold Kim , Byham Stephanie
Published: February 2020

The emergence of hydrogen and fuel cell technologies offers the nation important and potentially transformative cross-sectoral economic, environmental and energy security benefits that are being explored through the U.S. Department of Energy’s (DOE) H2@scale initiative. Through H2@Scale, DOE is partnering with more than twenty companies as well as America’s national laboratories to realize hydrogen as a flexible, scalable, nationwide energy carrier, complementing the electric grid in service of major energy, industry and transportation sectors. In recent years, early-stage research and development supported by DOE’s Fuel Cell Technologies Office has contributed substantially to the advancement of important hydrogen and fuel cell technologies which are critical to the H2@Scale vision. One example has been the research efforts to develop multiple pathways for large-scale hydrogen production from diverse domestic resources through the HydroGEN Consortium on Advanced Water Splitting Materials, which is part of the DOE Energy Materials Network. HydroGEN research efforts leverage state-of-the-art methods in theory, computation, experimentation, analysis, and data informatics in the discovery and development of efficient and durable materials for hydrogen production through innovative electrochemical, solar-thermochemical and solar-photoelectrochemical pathways. Recent HydroGEN activities and progress in areas of electrochemical water splitting will be described and discussed in the context of H2@Scale.
Insight in Mass Transport of Polymer Electrolyte Water Electrolyzer By Systematic Analysis of Liquid and Gas Fed Water
Authors: Schuler Tobias , Kimura Taro , Schmidt Thomas J. , Büchi Felix N
Published: February 2020

For a broader commercialization of polymer electrolyte water electrolysis (PEWE), it is essential to gain a fundamental understanding of the different components and related losses to increase the overall system efficiency to further decrease the operating cost. Mass transport resistances are the least understood loss category. The use of water feed in the vapor state was utilized to gain insight in the origin of mass transport losses. Vapor feed amplifies governing transport parameters. Limiting current densities were determined and mass transport resistances calculated as a function of temperature (60°C-80°C) and relative gas humidity (60% to >100% rH i.e. oversaturation). The studied configurations with symmetric and asymmetric cell humidification exemplify the major impact of water drag and diffusion on the performance. In addition, a relation between mass transport limitation and high frequency resistance (HFR) measured by electrochemical impedance spectroscopy was established.

The overall mass transport resistance is composed of the sub-resistances of the catalyst layer and the PTL. Partial pressure and PTL type variation were used to isolate these main resistances. The catalyst layer was identified to be the governing resistance in the system such that gas feed electrolysis features two order of magnitude lower current densities in comparison to liquid water electrolysis [1] (see also Figure 1). In the diffusion limited regime of the gas feed cells the limits of liquid water electrolysis are emphasized. The origin of the significant liquid/vapor feed differences was investigated by using different PTL types and IrO2 loadings. The required CCMs were produced by an automated spray coating process where IrO2 loading was varied between 1.0 mg/cm2 and 3.0 mg/cm2.

references

[1] J.M. Spurgeon, N.S. Lewis, Proton exchange membrane electrolysis sustained by water vapor, Energy & Environmental Science, 4 (2011) 2993-2998.

Figure 1
High Efficiency Proton Exchange Membrane Electrolysis: Potential for H2@Scale
Authors: Ayers Katherine E. , Capuano Christopher B , Mani Prasanna
Published: February 2020

Sustainable sources of hydrogen are a key need for reducing environmental impact of chemical processes, with over 95% of hydrogen for industrial applications currently made from fossil fuels through natural gas reforming or coal gasification. Hydrogen is an important industrial gas, representing a 10 million metric tons/year industry worth $100 billion. While proton exchange membrane (PEM)-based water electrolysis has been commercially available for many years, the production scale has been too small until recently to make large impacts. Also, because of the legacy of the technology in life support applications and lower R&D investment relative to PEM fuel cells, there is still significant room for cost and efficiency improvement of PEM electrolysis through materials and manufacturing advancements.

This talk will discuss recent work in high efficiency catalysts and membranes and fundamental challenges in translating laboratory tests to manufacturable components. While catalyst composition and structure is important in understanding and increasing activity, integration is also a key part of materials and technology development. Solution data is not sufficient for predicting behavior in solid state electrolytes or interfaces with other cell components. Most laboratory experiments also do not provide sufficient information on durability beyond a screening tool for early stages of testing. A holistic approach is needed in materials, processing, and component interactions to advance the field. Current technology scale for PEM electrolysis and pathways for large scale renewable hydrogen production will also provide a framework for potential impact in the near term.
High-Performance Praseodymium Doped Pyrochlore-Type Yttrium Ruthenate Electrocatalysts for Proton Exchange Membrane Water Electrolysis
Authors: Feng Qi , Zhang Zhen , Yao Yao , Li Hui , Wang Haijiang
Published: February 2020

Proton exchange membrane water electrolysis (PEMWE) is an advanced and effective solution to the primary energy storage which allows for direct production of hydrogen from water. Due to the harsh electrochemical environment (e.g., high anodic overpotential, the presence of strong oxidants, low PH) and the sluggish electrode processes, precious metal compounds have been chosen as electrocatalysts in PEMWE [1]. The development of low-cost, highly active and stable oxygen evolution reaction (OER) catalysts remains an important challenge. Pyrochlore yttrium ruthenate (Y2Ru2O7−δ) has significantly enhanced performance over conventional IrO2 electrocatalyst towards OER and high stability in acid media [2]. However, Y2Ru2O7−δ is limited by its low electrical conductivity related to the n-type semiconducting behavior [3]. Doping the A site of the pyrochlore structure (A2B2O7−δ) is a strategy to improve the electrical conductivity of pyrochlore materials.

In this work, novel yttrium–ruthenates compositions doped with Pr were synthesized by sol-gel method. Electrochemical measurements in acidic media showed that Pr doped yttrium pyrochlore catalysts possess high OER activity and stability. The OER overpotentials of Y2Ru2O7−δ and Y1.8Pr0.2Ru2O7−δ are 310 mV and 300 mV at 10 mA/cm2, which is lower than that of IrO2 (340 mV). The Tafel slopes for Y2Ru2O7−δ and Y1.8Pr0.2Ru2O7−δ are 40 mV/dec and 36 mV/dec, respectively, in comparison with 42 mV/dec for IrO2. The superior activity of Y2Ru2O7−δ and Y1.8Pr0.2Ru2O7−δ measured by current density remained largely unchanged even after 2000 cyclic voltammograms (CVs) cycles, only decreasing by 17% and 5.6%, respectively. In contrast, IrO­2 catalyst lost 46% of its activity.

Figure 1. OER performance of pyrochlore Y2Ru2O7, Y1.8Pr0.2Ru2O7 and reference IrO2 electrocatalysts. (a) CVs cycles from 1st to 2 000th. Inset shows the comparison of current densities for yttrium ruthenate and IrO2 at 1.52 V versus RHE. (b) Tafel plots.

[1] Q. Feng, X.Z. Yuan, G. Liu, B. Wei, Z. Zhang, H. Li, H. Wang, Journal of Power Sources, 366 (2017) 33-55.

[2] J. Kim, P.C. Shih, K.C. Tsao, Y.T. Pan, X. Yin, C.J. Sun, H. Yang, J Am Chem Soc, 139 (2017) 12076-12083.

[3] C. Abate, V. Esposito, K. Duncan, J.C. Nino, D.M. Gattia, E.D. Wachsman, E. Traversa, Journal of the American Ceramic Society, (2010).

Figure 1
First-Principles Models of Phenomena at Li-Metal/Anti-Perovskite Li3ocl Solid Electrolyte Interfaces
Authors: Kim Kwangnam , Siegel Donald J
Published: February 2020

Solid electrolytes (SE) are a promising strategy for enhancing the safety of lithium-ion batteries (LIBs). Additionally, a viable SE could allow the use of a Li-metal anode, which would increase energy density. Recently, the anti-perovskite compound, Li3OCl (LOC), was suggested as a high conductivity SE, with many follow-on studies investigating Li-ion migration mechanisms and pathways for further increasing conductivity. However, the properties of the interface between LOC and a Li metal electrode are also important for performance. For example, the interaction between a SE and an electrode can change the band edge positions of a SE, narrowing its electrochemical window. Furthermore, wetting of the SE by Li metal is desirable for low interfacial resistance and uniform Li plating.

The present study predicts the interfacial energy, wettability, band edge shifts, and the electrochemical window for interfaces between LOC and a Li-metal anode. The oxygen-terminated interface was determined to be the most stable interface termination. The calculated interfacial work of adhesion suggests that Li will wet LOC with a contact angle of 52.6˚, suggesting the possibility for low interfacial resistance and uniform Li deposition. On the other hand, the strong interfacial adhesion significantly narrows the electrochemical window by shifting both of the LOC band edges by more than 1 eV. Nevertheless, the band edges are predicted to be located above the Li/Li+ level and below the presumed level for a 4.5 V cathode, which implies a sufficiently wide electrochemical window. Our results illustrate a holistic and systematic strategy for characterizing electrode/electrolyte interfaces in solid state batteries.
Accelerated Phase Transition of Pr2NiO4 in the Presence of GDC Interlayer
Authors: Wilson Joshua A. , Wang Yudong , Zhou Xiao-Dong
Published: February 2020

Praseodymium Nickelate (Pr2NiO4) has the potential to be a cathode for commercial solid oxide fuel cells (SOFCs) due to its high activity towards oxygen reduction. However, when Gd-doped Ceria (GDC) is used as an interlayer to prevent cathode-electrolyte interaction, phase transitions in Pr2NiO4 are accelerated. The accelerated phase transition in Pr2NiO4 decreases the stability of the cell, leading to faster degradation rates in performance over the lifetime of the cell. Identifying how the GDC interlayer affects phase transition will increase the effectiveness of Pr2NiO4 as an SOFC cathode. In this work, the accelerated phase transition of Pr2NiO4 in the presence of GDC will be investigated by: (1) thermo-annealing mixtures of Pr2NiO4/GDC powders at varying compositions and temperatures and, (2) constructing and analyzing cells with Pr2NiO4-GDC composite electrodes and GDC interlayers. XRD will be used to analyze the resulting phase transitions of the annealed powders and of the operated cells. Identifying structural and operational dependencies of this mechanism may help us develop approaches to increase the long-term stability of SOFCs with Pr2NiO4 as cathode material.

Keywords: Nickelate, Doped ceria, phase transition, solid oxide fuel cell
Comparative Study: Effect of Various Wet Impregnations into LaNi1-XFexO3-Δ Cathodic Backbone for Solid Oxide Fuel Cells
Authors: Kang Hung-Sen , Li Haoyu , Lee Min Hwan
Published: February 2020

The performance of solid oxide fuel cells (SOFCs) is often limited by the sluggish oxygen reduction reaction (ORR) process at the cathode. It is also widely believed that the surface exchange kinetics and surface area of cathodes play a pivotal role in determining the overall cathodic performance. For this reason, various efforts have been made to improve these metrics through nanoscale materials engineering, most notably by the wet impregnation (infiltration) method.[1] While numerous studies have proved the dramatically beneficial effect of infiltration, a systematic comparative study revealing the effect of infiltrated materials and their concentration is lacking.

In this study, we investigated the effect of infiltrated material and nitrate concentration used for sol-impregnation process on the resulting kinetics and rate-limiting steps of ORR. Various infiltrates were chosen based upon the specific merits of each material in terms of electronic/ionic conductivity, oxygen exchange activity and oxygen storage capability. The infiltrates of study includes LaxSr1-xCoyFe1-yO3-δ (LSCF), La1-xSrxMnO3-δ (LSM), Gd1-xCexO2-δ (GDC), Sm1-xCexO3-δ (SDC), Pr1-xCexO3-δ (PDC), Pr6O11 and LaNi1-xFexO3-δ (LNF). Porous LNF was used as the cathodic backbone. For each infiltrate type, sols with different molar concentrations ranging from 0.2 M to 5.0 M were applied for the infiltration process. For every infiltration process, only one infiltration process was performed without a separate sintering/annealing step.

Results showed that an infiltration even with LNF, the same material with the backbone reduced the cathodic polarization resistance (Rp
) from 2.6 (bare LNF) to 0.15 W cm2 at 700 °C, indicating the critical importance of active surface area for cathodic performance in this system. Infiltration with 1.0 M of Pr6O11 rendered the best performance (Rp
= 0.055 W cm2 at 700 °C). With a concentration of 1.0 M or higher, the infiltrate comprises > 20 wt.%, a concentration high enough to infiltrate Pr6O11 throughout the surface of LNF backbone uniformly as observed by electron microscope images. The activation energy of cathodic polarization decreased from 1.75 eV (bare LNF) to 1.0 – 1.2 eV (1.12 eV for 1 M LNF; 1.18 eV for 1 M Pr6O11, 1.06 eV for 1 M LSCF), indicating a shift in the rate limiting step by the infiltration. There was, however, little dependency of activation energy on the molar concentration in a given infiltrate material as long as the concentration is > ~0.5 M. In addition, the dependency on oxygen partial pressure also provided critical clues on the shift in the rate-limiting steps of ORR, and relevant discussion will be provided in the presentation.

This work was supported by the NASA MIRO Program (NNX15AQ01A).

References

[1] D. Ding, X. Li, S. Y. Lai, K. Gerdes, M. Liu, Energy Environ. Sci.
2014, 7, 552.

Figure 1
Preparation and Characterization of Alternative Ni-Based Anode Materials for SOFCs
Authors: Ishibashi Yusuke , Futamura Shotaro , Tachikawa Yuya , Matsuda Junko , Shiratori Yusuke , Taniguchi Shunsuke , Sasaki Kazunari
Published: February 2020

Introduction

Ni is widely used as the anode material of SOFCs as a cermet containing ionic conductor and electronic conductor. In the SOFC power generation, the oxygen partial pressure in the downstream region of the SOFC systems increases, the metallic Ni can be oxidized to NiO, and thus volume expansion occurs1. Aggregation of adjacent Ni particles can degrade the electrode structure, which makes it difficult to fully utilize the fuel supplied. We have succeeded in fabricating an SOFC anode which is resistant to redox cycling using oxide conductors, La-doped SrTiO3 (LST) and Gd-doped CeO2 (GDC). In this study, we aim to develop (i) a novel electrode in which a metallic Ni catalyst is dissolved from the electrode material and precipitated on the surface of the anode in a reducing atmosphere (Ni-LST-GDC anode), and (ii) a novel electrode using a Ni-based alloy in the electrode framework (Ni-alloy-GDC anode)2,3.

Experimental

Alternative anode materials were prepared via wet process2,3. The cells were prepared by screen-printing the anode and the cathode followed by each sintering process in air. A platinum mesh was used for the current collector, and a Pt-based reference electrode was deposited on the cathode side for overvoltage separation between the anode and the cathode. The electrochemical performance of the fuel cells was evaluated from the I-V characteristics at the operating temperature of 800°C, using 3%-humidified hydrogen fuel. In order to evaluate the electrode activity, the electrode overvoltage was measured. The current interruption method was applied for evaluating the electrode overvoltages.

Results and discussion

Figure 1 shows the I-V characteristics of the cells with the newly prepared Ni-LST-GDC anode, the Ni-impregnated anode, and the LST-GDC anode without adding Ni, at 800°C, in 3%-humidified hydrogen fuel. Regarding the anode voltage and the anodic overvoltage, the Ni-LST-GDC anode exhibited better performance than the anode composed only of LST and GDC. In comparison with the Ni-impregnated anode, however, the cell performance was still lower both in anode voltage, overvoltage, and IR loss. Figure 2 shows STEM micrographs indicating that the Ni catalyst particle precipitated could locate on the GDC. Anode materials design principles of alternative Ni-based anodes will be discussed. But most of Ni particles located on the electron-conductive LST. In contrast, the cell with Ni-alloy anode exhibited comparable performance compared to that with the Ni-SSZ cermet.

References

[1] Q. Fang, L. Blum, R. Peters, M. Peksen, P. Batfalsky, D. Stolten, Int. J. Hydrogen Energy, 40, 1128-1136 (2015).

[2] X. Shen and K. Sasaki, J. Power Sources, 320, 180 (2016).

[3] S. Futamura et al., J. Electrochem. Soc., 164 (10), F3055 (2017).

Figure 1
Performance Improvement of Solid Oxide Cells Using CuO Sintering Aid for Co-Sintering of GDC Buffer Layer and La0.6Sr0.4Co0.2Fe0.8O3-δ Air Electrode
Authors: Choi Hyun-Jong , Kim Sun-Dong , Kim Tae Woo , Seo Doo-Won , Woo Sang-Kuk
Published: February 2020

The effects of a Cu-based additive and nano-Gd-doped ceria (GDC) sol on the sintering temperature for the construction of solid oxide cells (SOCs) were investigated. A GDC buffer layer with 0.25–2 mol% CuO as a sintering aid was prepared by reacting GDC powder and a CuN2O6 solution, followed by heating at 600 °C. The sintering of the CuO-added GDC powder was optimized by investigating linear shrinkage, microstructure, grain size, ionic conductivity, and activation energy at temperatures ranging from 1000 to 1400 °C. The sintering temperature of the CuO–GDC buffer layer was decreased from 1400 °C to 1000 °C by adding the CuO sintering aid at levels exceeding 0.5 mol%. The ionic conductivity of the CuO–GDC electrolyte was maximized at 0.5 mol% CuO. However, the addition of CuO did not significantly affect the activation energy of the GDC buffer layer. Buffer layers with CuO-added GDC or nano-GDC sol-infiltrated GDC were fabricated and tested in co-sintering (1050 °C, air) with La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF). In addition, SOC tests were performed using button cells and flat tubular type five-cell stacks. The button cell exhibited the maximum power density of 0.89 W cm−2 in solid oxide fuel cell (SOFC) mode. The stack operated more than 1,000 h in solid oxide electrolysis cell (SOEC) mode.
A New Triple-Conducting Material for Efficient Hydrogen Production in Proton Conducting Solid Oxide Electrolysis Cells
Authors: Ding Dong , Ding Hanping , Wu Wei , He Ting
Published: February 2020

Steam electrolysis through solid oxide electrolysis cells (SOECs), are promising alternatives to steam reforming reaction for hydrogen generation in specific applications owing to its very high efficiency and clean products. However, the state-of-art SOEC relied on oxygen ion conductors (O-SOECs) that were required to be operated at high temperatures (>850oC). Proton conducting SOECs (P-SOECs) are emerging technologies that used proton conductor as the electrolyte and can be run at reduced temperatures, overcoming those O-SOECs’ problems such as fast degradation, and hydrogen separation, etc. The challenges of P-SOEC is poor performance with sluggish electrode kinetics at reduced temperatures as well as unproven stability. In this work, we report our findings in design, fabrication, and characterization of an extremely highly efficient P-SOEC with a novel triple-conducting steam electrode below 600oC in INL. The performance and durability of the P-SOECs exhibited significant improvement in comparison to those existing O-SOECs and P-SOECs.
NiO-GDC10/GDC10/LSCF-GDC10 Manufactured By Tape Casting and Reactive Magnetron Sputtering Processes of Solid Oxide Fuel Cells
Authors: Hernandez Londono Carlos
Published: February 2020

We developed a cost–effective a method to manufacture performance planar solid oxide fuel cells using composite electrode by tape casting and electrolyte by reactive magnetron sputtering. NiO and GDC (10% Gd), used for the anode-supported (as) and the anode functional layer (afl) powders were milled by using zirconia balls in a Turbula-(System Schatz from WAB) times up to 24 hours. Half-cell, 28 mm of diameter, Ni-GDC composite anodes have been fabricated by slurry based tape casting (Elcometer4340 Automatic Film Applicator) method for anode supported solid oxide fuel cell. Depending on the results, work on the support anode (AS) Ni0-GDC will continue in particular to avoid the presence of the residual phase of carbon resulting from the use of an agent poro formers with graphite . The decomposition of organic additives and the shrinkage of green tape is analyzed thermo-gravimetric and differential thermal analysis (TG) of anode. PVD by plasma emission monitoring (PEM) was employed to synthesize GDC (10%Gd doped ceria) thin films on anode-grade ceramic substrate (porous NiO-GDC10). 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 under reactive atmosphere.The cathode, which is made of (LSCF-GDC10) was screen printed onto electrolyte film and sintered to form a complete SOFC. The obtained cell after sintering was seen without any deformation or crack. Pycnometry and porosimetry techniques were primarily used to determine pore size and pore volume by equation Washburn and Ideal gas law-method and the decomposition of organic additives and the shrinkage of green tape was analyzed thermo-gravimetric of NiO-GDC10 and LSCF-GDC10. The microstructural morphological surface features of the cell was by 3D profilometry and complete cell were analyzed by Scanning Electron Microscopy (SEM), XRD and was employed to nos-destructively quantify the craking and behavior observed before and after different annealing. The measurements will be carried out on a complete cell with the measuring bench of the company Fiaxell of 5*5 cm2 and on a cell of 28 mm of diameter in order to obtain curves I / V.
Self-Referencing Luminescence Thermometry with Probes Emitting Red and NIR
Authors: Dramicanin Miroslav
Published: February 2020

Luminescence of any substance is strongly affected by temperature. Therefore, in principle, any material may be utilized to determine temperature from changes in its excitation and emission band energies and bandwidths, emission intensities, ratios of intensities of different emission bands, polarization/anisotropy, emission decay- and rise-times [1, 2]. However, for practical applications in thermometry, materials and material’s systems ought to be thermally and chemically stable, have sufficient brightness and photostability, and their luminescence should notable change with temperature.

Today, lanthanide and transition metal activated phosphors, quantum dots, organic dyes and pigments, and metal-organic complexes and frameworks are common choices for luminescence thermometry probes. Among them, due to compatibility with the biological “optical window” and low interference from light scattering and background fluorescence, those probes emitting in the red and near-infrared parts of the electromagnetic spectrum are of exceptional interest for bio-medical applications.

Here, the focus is on the emission intensity ratio and emission decay based luminescence thermometry methods because they are self-referencing (do not require reference measurements) and are not affected by changes in measurements conditions. The principle of operation of these methods is presented along with corresponding figures of merit. Then, the main red- and NIR-emitting materials utilized for thermometry probes are listed and their performance is discussed. These include Eu3+, Nd3+, Cr3+ and Mn4+ activated phosphors, PbSe, PbS, CdSe/ZnS and PbS/CdS/ZnS core–shell, ZnS−AgInS2 alloy, ZnS:Mn2+, CsPbCl3:Mn2+ quantum dots, and organic Pluronic F127–Cy5.5 hybrid probe and metal-organic Eu0.0069Tb0.9931-2,5-dimethoxy-1,4-benzenedicarboxylate probes. Finally, several examples of multifunctional applications of these probes and methods is shown, such as in combined bio-imagining and thermal sensing, photothermal therapy and combined physical and chemical sensing.

References:

M.D. Dramićanin, Luminescence Thermometry: Methods, Materials, and Applications 1ed, Elsevier Ltd, ISBN: 978-0-08-102029-6, 2018.

M.D. Dramićanin, Sensing temperature via downshifting emissions of lanthanide-dopedmetal oxides and salts. A review, Methods Appl Fluoresc 4 (4) (2016) 23. 42001.
Luminescence Thermometry with Dy3+ Activated Na0.25K0.25Bi0.5TiO3
Authors: Medic Mina , Dacanin Far Ljubica , Kuzman Sanja , Petrovic Dragoslav M. , Dramicanin Miroslav , Lukic Petrovic Svetlana R.
Published: February 2020

In this report we present synthesis and thermographic properties of Dy-activated Na0.25K0.25Bi0.48Dy0.02TiO3 powder. The material is prepared by a solid-state reaction using TiO2, Bi2O3, Na2CO3, K2CO3 and Dy2O3 as precursor materials. Starting powders were ball milled in ethanol for 12 h, then dried and calcined at 850°C for 2 h. Subsequently, the obtained powder was additionally milled in ethanol for 12 h, and finally sintered at 850°C for 4 h. X-ray diffraction measurement revealed that NKBT sample exhibits a tetragonal perovskite structure, belonging to the P4bm space group, without impurities. Emission spectra showed characteristic bands of Dy3+ ions with pronounced emission originating from f–f electronic transitions. A dominant band in the blue region with maximum at around 477 nm originates from magnetic-dipole 4F9/2→6H15/2 transition, while another one in the yellow region peaking at around 574 nm comes from electric-dipole 4F9/2→6H13/2 transition. A small intensity high-energy band centered at around 457 nm originating from 4I15/2→ 6H15/2 transition, provided the possibility to use this type of emitting material as temperature sensor in luminescence thermometry. Temperature readings from material’s luminescence emission were acquired via relative luminescence emission intensity measurements (LIR). This approach uses the ratio of intensities of two specific emission bands, in this case emissions from 4F9/2 and 4I15/2 excited states to the 6H15/2 ground state [1, 2]. With this material, relative sensitivity of about 2% K-1 and temperature resolution of 0.5 K of thermometry have been achieved.

References:

Ž. Antić, M. D Dramićanin, K. Prashanthi, D. Jovanović, S. Kuzman, T. Thundat, "Pulsed Laser Deposited Dysprosium-Doped Gadolinium–Vanadate Thin Films for Noncontact, Self-Referencing Luminescence Thermometry", Advanced Materials, Volume 28(35), 7745-7752 (2016).

M. D Dramićanin, "Sensing temperature via downshifting emissions of lanthanide-doped metal oxides and salts. A review", Methods and Applications in Fluorescence, Volume 4(4), 042001(23 pp) (2016).
Structure Solution and Luminescence Properties of a Phosphosilicate Compound
Authors: Kim Ha Jun , Unithrattil Sanjith , Im Won Bin
Published: February 2020

Materials with different frameworks and topologies have an important place in various scientific applications, and several such compounds have been developed over the past few years. The insights offered by such developments have altered the thought process behind material formation and their potential topologies. Materials with certain particular frameworks are often channelized toward specific applications, based on the understandings then; however, these materials may also offer a considerable number of topologies and are finding new applications that were considered unviable a few decades ago. Among the most prominent and well-understood materials that form such frameworks are aluminosilicates. Although most of these classes of compounds are natural in origin, specific applications based on these materials have only recently been developed, because of limitations in understanding their precise chemical and structural details.

In this work, we synthesized a new phosphosilicate compound, using a microwave-assisted solid-state synthesis method. The lattice parameters of the crystalline compound were estimated from first-principle calculations, and the space group was identified through a least-squares method. The detailed structure solution was carried out through a simulated annealing method, which estimated the agreement between the assumed model and the observed diffraction pattern and chemical restraints. Therefore, the crystal structure solved was verified through the Rietveld refinement and maximum-entropy method (MEM) analysis. High-resolution transmission electron microscopy (HRTEM) was also used to confirm the lattice parameters of the solved crystal structure. Photoluminescence properties of the structure were also studied by activating it with the broadband-emitting activator (Eu2+), and the structural and luminescence correlation was also verified.

Figure 1. Rietveld refinement of the powder X-ray diffraction profile of NaCa3PSiO8. Data (point) and fit (lines), different profile, and expected reflection positions are displayed. The inset shows the coordination environment of the major cations in the structure.

Figure 1
Fast Ion Conducting Solid-State Electrolytes for Sodium Ion Batteries — from Elementary Steps to Macroscopic Transport
Authors: Lunghammer Sarah , Wilkening Martin
Published: February 2020

All-solid-state batteries and especially solid electrolytes stand in the spotlight of current energy research.[1,2] An extremely high ion mobility, which is known for liquid electrolytes, is needed to realize batteries with ceramic electrolytes. Apart from Li-bearing materials also a range of sodium compounds exhibit extremely high ion conductivities. With regard to availability and costs Na-based energy storage systems have attracted great interest over the last years.[3]

Here we re-investigated the most prominent representatives of this kind of functional materials viz. Na-β''-alumina[4] and Na3Zr2(SiO4)2PO4 (NASICON), which are known to show conductivity values in the order of mS/cm at RT.[5,6] We used high precision impedance measurements and nuclear magnetic resonance (NMR) spectroscopy to study the diffusion mechanisms and long-range ion transport. In the case of Na-β''-alumina we focused on a commercially available sintered pellets to investigate both bulk dynamics and grain boundary effects on ionic conductivity. Impedance spectroscopy was helpful to interpret ion dynamics revealed by NMR on both short as well as long-range length scales. For well-sintered and highly dense samples ion transport across grain boundaries has only little impact on the overall fast ion transport seen.

References:

[1] J.C. Bachman, S. Muy et al., Chem. Rev.
2016, 116, 140-162.

[2] J. Janek, W. Zeier, Nature Energy 1

2016, 16141.

[3] B. L. Ellis, L. F. Nazar, Curr. Opin. Solid State Mater. Sci.
2012, 16, 168-177.

[4] M. Bettman, C. R. Peters, J. Phys. Chem.
1969, 73, 1774-1780.

[5] W. Jakubowski, D. H. Whitmore, J. Am. Chem. Soc.
1979, 62, 381-385.

[6] J. Goodenough, H.-P. Hong et al., Mat. Res. Bull.
1976, 11, 203-220.
Organic Electrolyte Dependent Electrochemical Performance of Lithium metal anode Materials for Lithium-Metal Batteries
Authors: Lee Da-Yeon , Kim Seong In , Park Geun-gyung , Eom Ji-Yong
Published: February 2020

Lithium metal is the most attractive anode material for batteries because of its high specific capacity and low negative potential. However, lithium dendrite growth during lithium deposition leads to serious safety problems and poor cycling performance.

According to the previous reports, the electrochemical performance of lithium metal anode material for LIBs highly depends on the composition and physicochemical properties of the electrolytes used. However, a key factor with regard to electrolytes that can determine the electrochemical characteristics of the anode materials is not fully understood yet.

Thus, in the present work, we observed the electrochemical performance of lithium metal anode material as a function of electrolyte parameters, and elucidated the chemical/electrochemical reaction behavior of various electrolytes on the surface of lithium metal.
Thiadiazoles As Anolytes for Nonaqueous Redox Flow Cells
Authors: Huang Jinhua , Duan Wentao , Zhang Jingjing , Shkrob Ilya A , Assary Rajeev , Wei Xiaoliang , Zhang Lu
Published: February 2020

Understanding structure-property relations is essential for designing energy-rich redox active materials (ROMs) for all-organic redox flow batteries.1-2 Herein we examine thiadiazole ROMs for storage of negative charge in the flow cells.3 These versatile molecules have excellent solubility and low redox potentials, allowing to achieve high energy density. By systematically incorporating groups with varying electron accepting/withdrawing ability, we have examined substituent effects on their properties of interest, including redox potentials, calendar lives of charged ROMs in electrolyte, and the flow cell cycling performance. While the calendar life of energized fluids can be tuned in a predictable fashion over a wide range, the improvements in the calendar life do not automatically translate into the enhanced cycling performance, indicating that in addition to the slow reactions of charges species in the solvent bulk, there are other parasitic reactions that occur only during electrochemical cycling of the cell and can dramatically affect the cycling lifetime. This finding strongly indicates the significant role of structural engineering in achieving improvement of radical ion stability, suggesting a generic guidance for developing long-cycling ROM-based flow cells. With these molecules we are on the very edge of possibility, reaching the compromise between the highest energy density and the stability of the radical anion that can be achieved in acetonitrile. We believe that setting these limits is more important for the energy storage community than surveying of different classes of the anolytes.

Figure 1 Structures and cyclic voltammogram of benzothiadiazole derivatives and the correlation of the half-decay lifetime of the radical anions with the redox potentials. Mind the logarithmic vertical scale.

Zhang, J.; Yang, Z.; Shkrob, I. A.; Assary, R. S.; Tung, S. o.; Silcox, B.; Duan, W.; Zhang, J.; Su, C. C.; Hu, B.; Pan, B.; Liao, C.; Zhang, Z.; Wang, W.; Curtiss, L. A.; Thompson, L. T.; Wei, X.; Zhang, L., Annulated Dialkoxybenzenes as Catholyte Materials for Non-aqueous Redox Flow Batteries: Achieving High Chemical Stability through Bicyclic Substitution. Advanced Energy Materials
2017,
7 (21), 1701272-n/a.

Zhang, L.; Zhang, Z.; Redfern, P. C.; Curtiss, L. A.; Amine, K., Molecular engineering towards safer lithium-ion batteries: a highly stable and compatible redox shuttle for overcharge protection. Energy & Environmental Science
2012,
5 (8), 8204-8207.

Duan, W.; Huang, J.; Kowalski, J. A.; Shkrob, I. A.; Vijayakumar, M.; Walter, E.; Pan, B.; Yang, Z.; Milshtein, J. D.; Li, B.; Liao, C.; Zhang, Z.; Wang, W.; Liu, J.; Moore, J. S.; Brushett, F. R.; Zhang, L.; Wei, X., “Wine-Dark Sea” in an Organic Flow Battery: Storing Negative Charge in 2,1,3-Benzothiadiazole Radicals Leads to Improved Cyclability. ACS Energy Letters
2017,
2 (5), 1156-1161.

Figure 1
Electrochemical Performance of Sodium Polymer Battery Employing Polyurethane-Based Gel Polymer Electrolyte
Authors: Park Myung-Soo , Thangavel Ranjith , Lee Yun Sung , Kim Dong-Won
Published: February 2020

With limited amounts of fossil fuels and increasing demand for efficient energy management, lithium-ion batteries (LIBs) have been a leading power source for hybrid electric vehicles and large-scale energy storage systems. However, rising price of lithium sources has become a significant concern, caused by increasing market demand for lithium and limited amounts of lithium resources. In this respect, sodium-based batteries have been considered an alternative to the LIBs due to the abundance of sodium resources in nature.1 Like LIBs, enhancing the battery safety is a significant concern, because use of highly flammable organic solvents may trigger safety problems. Gel polymer electrolytes present many potential advantages, including enhanced safety, good interfacial contact, easy processing to make thin film and flexibility in the battery design, as compared to conventional separators.2 In this study, we prepared polyurethane (PU)-based gel polymer electrolyte (GPE) composed of PU polymer matrix and sodium-ion liquid electrolyte, which exhibited good compatibility with liquid electrolyte and superior electrochemical properties. The PU GPE was employed to assemble the Na/Na3V2(PO4)3 cells. Electrochemical performance of the sodium cells was enhanced by employing the PU GPE.

References

M.D. Slater, D. Kim, E. Lee and C.S. Johnson, Adv. Funct. Mater., 23, 947-958 (2013).

H. Gao, B. Guo, J. Song, K. Park and J.B. Goodenough, Adv. Energy Mater., 5, 1402235 (2015).

Figure 1