bluuebunny/crossref_metadata_2025 huggingface dataset:
(Invited) Ambient Pressure XPS: Revealing Elemental, Chemical, and Potential Information across a Wide Range of Electrochemical Systems
Authors: Crumlin Ethan J
Published: February 2020

Interfaces play an important role in nearly all aspects of life, and are essential for electrochemistry. Electrochemical systems ranging from high temperature solid oxide fuel cells (SOFC) to batteries to capacitors have a wide range of important interfaces between solids, liquids, and gases which play a pivotal role in how energy is stored, transferred, and/or converted. The ability to study these interfaces has proven to be difficult and is only further exacerbated by the limited number of techniques capable of operating under in situ/operando environments. To overcome these challenges, we use in situ/operando ambient pressure X-ray Photoelectron Spectroscopy (APXPS). APXPS is a photon-in/electron-out process that can provide both atomic concentration and chemical specific information at pressures greater then 20 Torr. Using synchrotron X-rays at Lawrence Berkeley Nation Laboratory, the Advanced Light Source has several beamlines dedicated to APXPS endstations that are outfitted with various in situ/operando features such as heating to temperatures > 500 °C, pressures greater then 20 Torr to support solid/liquid experiments and electrical leads to support applying electrical potentials supports the ability to collect XPS data of actual electrochemical devices while its operating in near ambient pressures. This talk will introduce this technique and provide several solid/gas and solid/liquid interface electrochemistry examples using operando APXPS including solid-state Li-air batteries, magnesium metal anode surface chemistry, and the ability to probe the electrochemical double layer (EDL). Gaining new insight to guide the design and control of future electrochemical interfaces.
(Keynote) Redox Catalysis for Redox Flow Lithium-Oxygen Battery
Authors: Wang Qing
Published: February 2020

Batteries are often the heaviest, costliest and the least-green component of electronic devices, and are currently the bottleneck in the large-scale deployment of stationary energy storage for smart grid and automotive energy storage for electric vehicles. Among various battery technologies, Li-O2 battery possesses the highest theoretical energy density and is regarded as the “Holy Grail” for next generation electrochemical energy storage. While numerous profound studies have been done to understand the battery chemistry, challenges relating to surface passivation and pore clogging by Li2O2 precipitation on the gas diffusion cathode remain. This severely impairs the round-trip energy efficiency and limits the achievable capacity of the cell. In this talk, a conceptually new and implementable solution — redox flow lithium-oxygen battery (RFLOB) [1] will be introduced, to address these critical issues confronted by Li-O2 battery. This novel device was devised based on reversible redox targeting of battery materials, and the recent advancement of redox flow lithium-ion batteries [2]. As demonstrated here, RFLOB combines great system flexibility of the redox flow battery with the extremely high energy density of the Li-O2 batteries, revealing significant advantages over other state-of-the-art electrochemical energy storage devices [3,4].

References:

[1] Y. G. Zhu, C. Jia, J. Yang, F. Pan, Q. Huang, and Q. Wang, Chem. Comm., 2015, 51, 9451-9454.

[2] C. Jia, F. Pan, Y. G. Zhu, Q. Huang, L. Lu, and Q. Wang, Science Advances, 2015, 1, e1500886.

[3] Y. G. Zhu, X. Wang, C. Jia, J. Yang, and Q. Wang, ACS Catalysis, 2016, 6, 6191–6197.

[4] Y. G. Zhu, et al., Nat. Commun., 2017, 8, 14308.
Sodium Superionic Conductor-Type Sodium Vanadium Fluorophosphates for Rechargeable Sodium-Ion Batteries
Authors: Hung Tai-Feng , Yeh Yu-Wen , Yang Chang-Chung , Chang Wen-Sheng , Hsueh Kan-Lin
Published: February 2020

Owing to the increasing demand for the electrochemical energy storage devices with sufficient capacity, high reliability and low cost, rechargeable sodium-ion batteries (SIBs) have recently regarded as alternative candidates to lithium-ion batteries (LIBs) because of their benefits on material abundance, cost-effectiveness and electrochemical similarities. However, the energy density delivered from the current SIBs is still not comparable with that of the LIBs, which was ascribed to the lower cell voltage. Therefore, developing the cathode materials with higher redox potentials is eagerly anticipated. As one of the most promising cathode materials, carbon-coated sodium vanadium fluorophosphates (Na3V2(PO4)2F3/C) nanocomposites have been extensively investigated due to the merits of their sodium superionic conductor (NASICON) structures for facile ionic transportations, high voltage and high capacity. In this study, the Na3V2(PO4)2F3/C nanoparticles were synthesized using a wet-chemistry route, followed by calcination in an argon atmosphere. The resulting powders were characterized by powder X-ray diffractometer, electron microscopes and thermogravimetric analyzer to confirm their crystalline structure, morphologies and amount of carbon loading, respectively. Benefiting from the nanostructures and continuous carbon coatings, the outstanding reversible capacity (128 mAh/g@0.1 A/g), rate capability (106 mAh/g@1.0 A/g) and capacity retention (98.2 %@100 cycles@1.0 A/g) were achieved as demonstrated by galvanostatic testing. Given the improved electrochemical properties, the NASICON-type Na3V2(PO4)2F3/C nanoparticles synthesized in the present study were anticipated to function as efficient cathode materials for SIBs.

Acknowledgement: We gratefully acknowledge financial support from the Bureau of Energy (BOE), Ministry of Economy Affair (MOEA), Taiwan.
Physicochemical Properties of Dialkyl Ethers
Authors: Nambu Noritoshi , Suzuki Shohei , Ogasawara Masaru
Published: February 2020

Ethylene glycol diethyl ether (1,2-diethoxyethane: DEE) is dialkyl ethers of ethylene glycol. The solubility of lithium salts in DEE is much less than that in ethylene glycol dimethyl ether (1,2-dimethoxyethane: DME) and ethylene glycol ethyl methyl ether (1-ethoxy-2-methoxyethane: EME). Partial fluorination of DEE increases the polarity. We have investigated the effect of the partial fluorination on the physical and electrochemical properties of DEE in some detail. The mass densities decreased in the order of decreasing the molar mass: tetrafluorinated DEE (FETFEE) > trifluorinated DEE (ETFEE) > monofluorinated DEE (EFEE) (≈ diethyl carbonate (DEC)) > DEE. The molar concentration of FETFEE was higher than that of ETFEE in spite of the large molar size: DEC > EFEE > DEE > FETFEE > ETFEE. The relative permittivity and viscosity of FETFEE were higher than those of ETFEE and EFEE: FETFEE > ETFEE ≈ EFEE > DEE > DEC for the relative permittivity and FETFEE > EFEE > ETFEE > DEC > DEE for the viscosity. The kinematic viscosity of ETFEE was as low as that of DEE above 50 °C. The partial fluorination of DEE improved the solubility of LiPF6. The electrolytic conductivity of 1 mol dm−3 LiPF6/FETFEE was lower than that of 1 mol dm−3 LiPF6/EFEE, but higher than that of 1 mol dm−3 LiPF6/ETFEE. The partial fluorination can increase the ability of the solvent molecules to form hydrogen bonds. The fluoromethyl group may serve as an anion-attracting group. The use of an EC−FETFEE equimolar binary mixture suppressed the discharge capacity fading at high cycle numbers.
Hybrid Battery System to Achieve High Power and High Energy for Automotive Applications
Authors: Kim Huiseok , Jung Seunghun
Published: February 2020

Although lithium-ion batteries (LiBs) have superior power and energy density than the other type of batteries, generally, a LiB is specially customized to achieve its specific requirements such as long-range mileage for EV or high power for HEV. This is because it is difficult to meet both high power and high energy density with a single type of battery. For example, high energy batteries for EVs that have thick electrodes may undergo charging problem such as lithium metal plating at low temperature. Accordingly, several studies were conducted to simultaneously improve both power and energy performance of LiBs. Using altered composition of electrode materials, electrolyte, and separator, LiBs could have improved energy retention or power performance [1-3]. But, preceding studies could not achieve both energy and power performance for vehicle applications at the same time. In order to resolve this problem, Kotz et al. [4] proposed a concept of a hybridized battery which combined a high energy battery with a high power capacitor within a single system. They reported that the internal parallel hybridization of those two components could achieve higher power and higher energy than each component operates independently.

 In the present study, we propose a new concept of battery system to achieve both high power and high energy at once by externally hybridizing a high power LiB with a high energy LiB in a single system, so called “hybrid battery (HB)”. To investigate the feasibility of the concept, we construct a mathematical model of a HB system as shown in figure 1. Three LiBs are connected in parallel. Two of them are high power LiBs and the other is high energy LiB. Conducting computational simulations with the developed model, basics characterization (OCV, resistance, C-rate performance) of the hybrid battery system is investigated for the first time. Then, we examine the performance of the hybrid battery under various operating conditions. Also, charging/discharging interactions among LiB members are monitored. To validate the present HB concept with the developed mathematical model, an actual hybrid battery system is constructed by using three automotive LiBs. Basic characterization and simulated driving test shows a good agreement with the theoretically predicted result. Through the present study we confirm the validity of the HB concept for automotive applications.

References

[1] Zonghai Chen, W.Q. Lu, J. Liu, K. Amine, Electrochemica Acta 51 (2006) 3322-3326

[2] Norio Takami, Hiroki Inagaki, Yoshinao Tatebayashi, Hidesato Saruwatari, Keizoh Honda, Shun Egusa, J Power Sources 244 (2013) 469-475

[3] Won-Kyung Shin, Ji-Hyun Yoo, Dong-Won Kim, J Power Sources 279 (2015) 737-744

[4] Dario Cericola, Petr Novak, Alexander Wokaun, Rudiger Kotz 196 (2011) 10305-10313

Figure 1
Design of Iron-Based Nanomaterials As Catalysts for Efficient Water Treatment and Electrochemical Energy Conversion
Authors: Abolhassani Mojtaba , Acharya Prashant , Foster Shelby L , Suttmiller David , Bakovic Sergio I. P. , Greenlee Lauren F
Published: February 2020

Materials design for iron-based nanomaterials in water treatment and electrochemical energy conversion has largely remained two distinct fields of research and engineering. Yet, the overall goals are the same; materials must be highly active for the target reaction, chemically stable with relevant lifetimes, and tunable for broad applicability and optimization in engineering systems. Further, the detailed characterization performed on catalysts in the electrochemistry arena could benefit efforts to develop catalysts and reactive materials in the water treatment community. Our research focuses on the development of iron-based catalysts and reactive nanomaterials for water contaminant degradation and alkaline electrochemical energy conversion applications, where we synthesize and tune nanoparticle properties, such as phase, composition, and morphology, to target specific reactions. In this talk, I will discuss key examples of how we synthesize our nanomaterials, our work on understanding the roles of nanoparticle structure and composition in reactivity, and opportunities for the synergistic blending of materials design and knowledge of how to design iron-based nanocatalysts for water and energy applications. In particular, an understanding of nanoparticle composition and phase in bimetallic iron-nickel hydroxide nanoparticles for alkaline water electrolysis supports our efforts to design similar catalysts for reductive degradation of the contaminant trichloroethylene, and we are also investigating the role of conductivity in carbon support materials used for water treatment applications. Our work on understanding how nanoparticle synthesis parameters affect nanoparticle performance has led to identification of specific parameters that may be tuned to optimize our catalysts for both arenas, and we have identified specific ligands used during solution-phase synthesis that are important to our catalytic reactions of interest. Overall, there remain many opportunities to draw from experimental progress made in both the water treatment and electrochemistry research communities, and I will touch on several key opportunities that we see in our work.
Amorphous Iron-Nickel (oxo)Hydroxide Nano-Particles Immobilized on SnO2 Nanotube Arrays As an Integrate Anode for Oxygen-Evolution Reaction
Authors: Xiang Rui , Wei Zidong
Published: February 2020

Key words: Oxygen evolution, Nanotube arrays, electro-catalysis

Development of efficient and earth abundant electro-catalysts for oxygen evolution reaction (OER) greatly hampered the realistic large scale production of hydrogen by electrolysers.[1] Bimetal iron/nickel (oxo)hydroxide represents a promising OER catalyst for its high intrinsic activity and stability.[2] To enhance its conductivity and density of active sits, we rationally immobilized amorphous FexNi(1-x)OOH nano-particles on SnO2 nanotube arrays by a mild all solution process. The SnO2 layer does not only function as a conductive matrix, but also guarantee the successful in-situ decoration of FexNi(1-x)OOH species instead of oxidative corrosion of the Nickel foam substrate by FeCl3 in the solution. Multiple physical characterizations confirmed the successful construction of the tubular architecture of SnO2 and the even dispersing of FexNi(1-x)OOH particles (SEM, TEM, XPS and Raman etc.). Its outstanding catalytic activity in basic solution in terms of a quite low overpotential of 250 mV at 50 mA cm-2 was demonstrated by electrochemical measurements (fig.1-h), and was ensured benefiting from the amorphous nature of FexNi(1-x)OOH nano-particles and the elegant tubular array micromorphology feature.

Fig. 1. SEM image (a, b) and element mapping (c, d, e, f and g) of NixFe(1-x)OOH/SnO2 nanotube arrays; (h) Linear Sweep Voltammetry (LSV) curves of NixFe(1-x)OOH@SnO2 NTA/Ni foam (purple), NiOOH@SnO2 NTA/Ni foam (blue), FeOOH@SnO2 NP/Ni foam (green), SnO2 NTA/Ni foam (red line) and bare Ni foam (black line) in alkaline solution. Dash line shows the LSV curve of NixFe(1-x)OOH@SnO2 NTA/Ni foam in the same solution with 70% iR compensation,. Condition: 1.0 M KOH. Scan rate 5 mV s-1.

Reference:

[1]. Nian-Tzu Suen, Sung-Fu Hung, Quan Quan, Nan Zhang, Yi-Jun Xu, Hao Ming Chen, Chem. Soc. Rev., 2017, 46, 337—365.

[2]. Shihui Zou, Michaela S. Burke, Matthew G. Kast, Jie Fan, Nemanja Danilovic, Shannon W. Boettcher, Chem. Mater. 2015, 27, 8011−8020.

Figure 1
(Invited) Lithium-Ion Capacitor Utilizing 3-D Current Collector with Bis(fluorosulfonyl)Imide-Based Electrolyte
Authors: Ishikawa Masashi , Hirota Naoya , Uchida Satoshi , Yamagata Masaki , Okuno Kazuki , Majima Masatoshi , Hosoe Akihisa
Published: February 2020

The lithium-ion capacitor (LIC) is a new storage device that combines an electric double-layer capacitor (EDLC) with a lithium-ion battery (LIB). Although LIC features an excellent power density like EDLC, the energy density of LIC is lower than that of LIB. Therefore, improvement of energy density is required for LIC. In the present study, to achieve high energy density of LIC, a porous 3-dimensinal (3-D) current collector is applied to LIC electrodes. This 3-D current collector can increase the packing density of active material. It is, however, expected that diffusion of ionic carriers is limited when we use a conventional organic electrolyte because an electrode based on a 3-D current collector should be massive and hence too long ionic diffusion pathways. As a result, LIC using a 3-D current collector may deliver limited power. Here ionic liquids (ILs) that have a high carrier density would be useful as an electrolyte for LIC to maintain power. The purpose of this study is applying IL-based electrolytes to LICs with the porous 3-D current collector.

We assembled a three-electrode cell. A positive electrode using an aluminum 3-D current collector was composed of activated carbon, acetylene black (AB) and polyvinylidene di-fruoride (PVdF). A negative electrode using a copper 3-D current collector was composed of hard carbon, AB and PVdF. A lithium foil was used as a counter electrode as well as reference electrode. We used lithium bis(fluorosulfonyl)imide/1-ethyl-3-methylimidazorium bis(fluorosulfonyl)imide (LiFSI/EMImFSI) as an IL-based electrolyte. The cell was charged and discharged for 3000 cycles at 1.0 C-rate in a voltage range of 2.0 – 3.8 V. We also evaluated rate performance of the LIC cells by rapid charging and discharging test up to 30 C-rate.

When we observed the potential profiles of the positive and negative electrodes during charge and discharge at the 2nd, 1000th and 3000th cycles, it was found that the LIC cell containing our FSI-based IL electrolyte can be charged and discharged reversibly as well as stably. Even though we applied long-term cycling such as 3000 cycles to the LIC cell, the capacity has not significantly degraded. We compared rate performance among the IL electrolyte and conventional organic electrolytes. Although the IL has a relatively high viscosity, it was shown that the FSI-based IL electrolyte has high rate performance comparable to that of a LiPF6-based organic electrolyte. This may be due to a high carrier density of the IL. These results suggest that application of the FSI-based IL electrolyte to LIC electrodes with the porous 3-D current collector is promising to keep or enhance energy and power capability.
A Step Potential Electrochemical Spectroscopy Analysis of Capacitance Fade with Increasing Film Thickness in Anodically Electrodeposited Thin Films of Manganese Dioxide
Authors: Gibson Andrew J , Donne Scott W
Published: February 2020

Manganese oxides (MnO2, MnOOH) are promising materials for electrochemical capacitors due to their low cost and toxicity, coupled with their attractive energy storage properties, and as such are well represented in the literature [1]. Thin films of MnO2 prepared by electrodeposition are capable of achieving high values for gravimetric specific capacitance (>2000 F/g) [2], however this rapidly decreases with increasing film thickness. Material activity, as well as material morphology play an important role in determining the capacitive behaviour of a material [3]. Recently, a new method for using step potential electrochemical spectroscopy to separate double layer and faradaic capacitance has been developed [4].

In this presentation, the change in both the double layer and faradaic capacitance with increasing film thickness of anodically prepared deposits will be discussed. With increasing film thickness the gravimetric double layer capacitance increases; however, this is significantly offset by a degradation in material activity, leading to an overall decay in material capacitance. The proposed structural and morphological reasons for these changes will be discussed.

1. Wei, W., et al., Manganese oxide-based materials as electrochemical supercapacitor electrodes. Chemical Society Reviews, 2011(40): p. 1697 - 1721.

2. Cross, A., et al., Enhanced Manganese Dioxide Supercapacitor Electrodes Produced by Electrodeposition. Journal of Power Sources, 2011. 196: p. 7847 - 7853.

3. Conway, B.E., Electrochemical Supercapacitors: Scientific Fundamentals and Technological Applications. 1999, New York: Springer.

4. Dupont, M.F. and S.W. Donne, A Step Potential Electrochemical Spectroscopy Analysis of Electrochemical Capacitor Electrode Performance. Electrochimica Acta, 2015. 167: p. 268 -277.
(Invited) Graphene Nanostructure By Molten Salt Process for Supercapacitor Applications
Authors: Kim Hyun-Kyung , Kumar R Vasant , Fray Derek John
Published: February 2020

Graphene has a two-dimensional honeycomb structure consisting of a single layer of carbon atoms with a sp2-bonding configuration and has recently attracted significant attention owing to its unique properties, which include an exceptionally high specific surface area and high electrical and thermal conductivities as well as mechanical and chemical stability. However, graphene sheets exhibit an extreme tendency to agglomerate or restack. This leads to a surface that is electrochemically less effective, low electrical conductivity, and an interlayer spacing that hinders access to electrolyte ions, thus limiting the use of the sheets in supercapacitor applications. Introducing spacer materials such as metal oxide, carbonaceous between the graphene sheets is a viable strategy for preventing the sheets from agglomerating.

In this study, we report the scalable fabrication of a high-quality hierarchical interconnected carbon nanostructure, combining two-dimensional graphene nanosheets and one-dimensional graphene nanoscrolls from graphite by a simple high temperature molten salt method. The electrode using the prepared material exhibited high reversible specific capacitance, excellent rate capability, and good cyclability because of their unique interconnected networks of carbon nanostructures with high electrochemically active surface area and high electrical conductivity.

More details on the synthetic procedure, electrochemical and structural properties will be presented at the meeting.
Highly Porous N-Doped Graphitic Carbon from Bio-Waste As Bifunctional Elactrocatalyst for Hybrid Na-Air Battery
Authors: Baskar Senthilkumar , Barpanda Prabeer
Published: February 2020

Rechargeable metal-air batteries have emerged as one of the most promising candidates for sustainable energy storage in the near future due to its high energy density [1,2]. In such a context, Lithium-air battery with a very high theoretical energy density (5200 Wh kg-1) received some very first attentions, but researchers soon realized that low Li abundance on Earth, poor cyclic stability and high operation overpotential make them not only high costs but also unrealistic in practical applications. More recently, Sodium-air batteries (Na-air) have risen as an effective alternate to Li-air batteries, given the facts that Na-air batteries are much safer and low cost. Na-air battery has several other advantages including low overpotential and high power density, arising from much higher ionic conductivity of Na-ion based solid electrolyte (e.g. Na3Zr2Si2PO12) and high solubility of discharge generated product (i.e. NaOH rather than LiOH) [3,4]. Based on cell design and electrolyte type, Na-air batteries can be classified into two major types: Non-aqueous and Aqueous (or) hybrid batteries [5]. Recent studies have shown that aqueous Na-air batteries hold some edges over non-aqueous systems, including low operation overpotential, higher rate capability, improved energy efficiency, and higher power density. Bifunctional catalysts are prominent to attain high capacity, maximum energy efficiency and long cycle-life for aqueous rechargeable Na-air batteries [6,7]. In this work, we report the synthesis of bifunctional noble metal free, highly porous N-doped graphitic carbon from bio-waste. The highly porous carbon showed higher specific surface area of 994 m2 g-1. Electrocatalytic property of the carbon based material was evaluated using linear sweep voltammetry with rotating ring disk electrode (RRDE). The N-doped graphitic carbon nanostructures showed better oxygen evolution activity compared to Pt/C catalyst. Highly porous N-doped graphitic carbon was investigated as a potential electrocatalyst for rechargeable hybrid Na-air battery for the first time. The fabricated hybrid Na-air battery with the N-doped graphitic carbon catalyst as air-cathode delivered low overpotential and its round trip energy efficiency reached above ~85 %. The hybrid Na-air battery exhibited stable cycle performance up to 20 cycles.

 

Acknowledgement

Author B.S. gratefully acknowledges the DST (SERB), New Delhi, India (PDF/2015/00217) for providing Fellowship.

References

[1] B. Dunn et al., Science 334(2011)928-935.

[2] J. Zhang et al., Nat. Nanotechnol. 10(2015)444-452.

[3] S. K. Das et al., J. Mater. Chem. A2(2014)12623-12629.

[4] P. G. Bruce et al., Nat. Mater., 11(2012)19-29.

[5] K. Hayashi et al., J. Electrochem. Soc., 160(2013)A1467-A1472.

[6] J-K. Kim et.al., NPG Asia Materials, 6(2014)e144.

[7] B. Senthilkumar et al., J. Power Sources, 311(2016)29-34.
Semiconducting Porous Carbon Spheres Derived from Hypercross-Linked Polymer for Energy Applications
Authors: Vinodh Rajanagam , Abidov Aziz , Palanichamy Muthiahpillai , Cha Wang Seog , Jang Hyun Tae
Published: February 2020

Herein we report a hypercross-linked polymers of semiconducting porous carbon material for supercapacitors application. Semiconducting carbonaceous material was prepared by two step method. A first, hypercross-linked polymer (HCPs) of anthracene was prepared by a simple Friedel Crafts alkylation, and then the synthesized microporous HCPs was subjected into carbonization at 600 °C in an inert atmosphere. The prepared material was characterized into cyclic voltammetry, galvanostatic charge-discharge and electrochemical impedance spectroscopy in 1M sodium sulphate aqueous solution. Further, the synthesized semiconducting material subjected in CO2 adsorption and shows maximum 8 weight % sorption at 25 °C.
Development, Manufacturing and Deployment of SOFC-Based Products at SOLIDpower
Authors: Bertoldi Massimo , Bucheli Olivier Franz , Ravagni Alberto
Published: February 2020

SOLIDpower provides efficient commercial SOFC generators based on its proprietary low cost planar SOFC technology. The company operates pilot manufacturing plants in Germany and Italy and performs development in Australia, Italy and Switzerland. Focusing initially on the domestic and commercial micro-generation market, the installed fleet has cumulated more than 13 Million operating hours so far. More than 700 BlueGEN systems have been installed and operated, mainly in Europe. The fleet has cumulated. The company expects to exceed 1’000 installations in 2017 and has started ramp-up to a 50 MW capacity. SOLIDpower has made first demonstration installations in the United States, the UL certification is in process to expand its markets also in the Unites States of America.

SOLIDpower is also a technology company that develops new applications based on the electrochemical membrane reactor. Besides co- and poly-generators of increased power level, also applications in the field of electrolysis and hydrogen generation are part of the development portfolio. For such specific developments, SOLIDpower establishes product development partnership with the end-user or system integrator.

The field of new applications opens new challenges on the material and engineering side of the systems that go beyond the classical cost reduction and performance increase questions. A few example of challenges will be presented.
Development and Commercialization of New Residential SOFC CHP System
Authors: Yoda Masakazu , Inoue Shuichi , Takuwa Yuya , Yasuhara Kenichirou , Suzuki Minoru
Published: February 2020

Osaka Gas began selling the new version residential SOFC CHP system “ENE-FARM type S” in April 2016, which is developed in collaboration with Osaka Gas, Aisin Seiki, Kyocera and Noritz. Kyocera manufactures SOFC stacks, Aisin Seiki manufactures power generation units, and Noritz manufactures boiler and remote-control units. The electrical efficiency is 52% (net AC, LHV), whereas that of the previous model was 46.5%.The previous system comprised two units: a power generation unit and a heat recovery unit. The latter unit contained the hot-water storage tank and the boiler. The new power generation unit contains the hot-water storage tank. This tank is configured for connection to a normal household boiler. The system size is minimized to facilitate its use as a residential CHP system. Moreover, it is possible to install the new system in a housing complex, where the available space is limited. This feature expands the market for this system because the previous model could only be installed in a single-family house.

To achieve the high electrical efficiency of 52% (net AC, LHV) and the cost reduction, three technical issues were addressed. The first was the improvement of the fuel cell performance, the second was the optimization of the fuel utilization rate, and the third was the improvement in durability. Kyocera reduced the internal electrical resistance of the fuel cell stack. In addition, a new coating technology, i.e., electropainting, which is developed by Osaka Gas and Kyocera, was used for current collectors. Consequently, both an increase in power density (reducing the number of cells) and an improvement in the electrical efficiency have been achieved. Current collectors are oxidized at a high temperature because they comprise stainless steel. Their durability has been considerably improved by the electropainting coating technology. Aisin Seiki optimized the system controls, resulting in enhanced electrical efficiency. Osaka Gas conducted field tests in the Kansai area in Japan. We installed the systems in the houses of several employees for evaluating the system behavior. The results made it possible to accelerate product development.

In accordance with the liberalization of the power market in Japan in April 2016, if customers use natural gas provided by Osaka Gas, the electrical power from the unit can be sold back to Osaka Gas. We consider that 2016 is a transition period for residential CHP from the market introduction stage to the autonomous market spread stage. We are currently focusing on achieving further developments in the technology, which will enable cost reduction and higher power generation efficiency in order to maximize the target market.
Counter Electrodes for Electrochemical Evaluation of LSM Electrodes under Polarization
Authors: Finklea Harry O. , Liu Jian , Yu Yang , Yan Miaolei , Abernathy Harry , Mersing David , Keplinger Dale
Published: February 2020

LSM electrodes are widely used in both solid oxide fuel cells and solid oxide electrolysis cells. The polarization and impedance behavior of the LSM electrodes are strong functions of the electrode’s prior history, such as current flow and temperature changes. It is desirable to measure polarization and impedance data of the LSM electrodes over a wide range of DC currents. With thin electrolytes, reference electrodes generally fail to isolate the behavior of a single electrode. We describe an alternate strategy in which the LSM electrode is paired with a LSCF counter electrode either on YSZ or on YSZ with a thin SDC layer. The LSCF electrode is quickly created by spray pyrolysis followed by rapid heating to a low sintering temperature. The LSCF electrode exhibits a polarization resistance at least an order of magnitude lower than the polarization resistance of the LSM electrode for cathodic and anodic current densities up to 1 A/cm2. Consequently, the observed polarization and impedance behavior of the cell is unambiguously assignable to the LSM electrode. At 800°C in air, the LSCF electrodes exhibit significant increases in polarization resistance with time, with the rate being lower on YSZ coated with a thin SDC layer. The strategy of creating a low impedance counter electrode by spray pyrolysis is broadly applicable and flexible with respect to electrode composition.
Electrode and Electrolyte Imaging in 3D: Field of View or Resolution?
Authors: Lemmens Herman , Jiao Chengge
Published: February 2020

Fuel cells and batteries depend on the transport of ions through a porous medium. The study of the 3D structure of these porous media is not straightforward. In general, a compromise must be made between resolution (which defines the smallest pore visible) and Field of View. There are different ways to create a 3D image of the porous medium; each with specific advantages and drawbacks.

MicroCT uses the absorption of X-rays to create a 3D reconstruction. The Field of View is large enough to be representative with regard to the grain sizes (1). However, the submicron porosity is typically not well captured by microCT because of its limited resolution.

The FIBSEM technique which uses a Galium ion beam for sectioning and an electron beam for imaging has high enough resolution to resolve all porosity. However, the Field of View is typically of the order of 10 micrometer; which is not big enough to create a representative model of the pore space.

In this study we have used a plasmabeam for sectioning and an electron beam for imaging. The plasmabeam typically removes a layer of 100 nm followed by imaging by the electron beam. The material removal rate with the plasmabeam is magnitudes higher than with the Ga focused ion beam, allowing to expand the field of view to hundreds of micrometers.

A 3D reconstruction of the pore space (Field of View 100 micrometer) make it possible to calculate parameters such as the tortuosity on a representative volume.

Segmentation of the pore space is not always straightforward due to minimal grey level differences between the different phases. Also, it is not uncommon to see details from layer N+1 through the pores in layer N. This so-called pore-back effect must be taken into account otherwise the permeability will be greatly underestimated.

Cai et al, Electrochimica Acta 56 (2011) 5804–5814
Exergy Efficiency Analysis of a Power-to-Methane System Coupling Water Electrolysis and Sabatier Reaction
Authors: Luo Yu , Wu Xiao-Yu , Shi Yixiang , Ghoniem Ahmed F. , Cai Ningsheng
Published: February 2020

Power-to-methane (PtM) systems coupling solid oxide electrolysis cell (SOEC) and Sabatier reactors offers an efficient and promising pathway to integrate the renewable/nuclear power with the existing natural gas network. SOEC operates at a higher temperature and yet produce hydrogen or syngas with a controllable H2/CO ratio with higher efficiency compared to low temperature electrolyzers. Besides, with the coupling of the SOEC and the Sabatier reactor, methane can be synthesized in one reactor from renewable energy. In this study, we firstly compared the power-to-hydrogen processes using the alkaline electrolysis cell (AEC), the proton exchange membrane electrolysis cell (PEMEC) and the SOEC. A factor of 38% is used to convert electricity to primary energy for first law efficiency analysis. Exergy efficiency analysis is also carried out to distinguish the qualities of the heat, electricity and gaseous fuels. The results show the PtM system using SOEC is more efficient than those using the other electrolysis technologies due to lower overpotential and better heat coupling. Particularly, the intermediate temperate SOEC exhibits a better heat coupling with the Sabatier reactor rather than the high temperature SOEC to further improve the system efficiency.

Figure 1
Electrochemical Performance and Stability of LSM-ESB Cathode
Authors: Huang Yi-Lin , Pellegrinelli Christopher , Painter Albert S , Wachsman Eric D.
Published: February 2020

Among (La0.8Sr0.2)0.95MnO3-δ (LSM) based cathodes LSM-(Er0.2Bi0.8)2O3 (LSM-ESB) composite shows promising performance and is one of potential cathodes for low temperature solid oxide fuel cells (LT-SOFCs). However, the high conductivity ESB exhibits oxygen-ordering at temperatures ≤600°C, resulting in an ordered super-lattice with low oxygen mobility. Here the electrochemical performance of LSM-ESB was investigated using electrochemical impedance spectroscopy (EIS) as a function of temperature, oxygen partial pressure (pO2), bias, and time to determine possible electrochemical reaction steps and elucidate the oxygen reduction reaction (ORR) mechanism. LSM-ESB shows a strong pO2 dependence and above 650°C the non-stoichiometry of LSM plays an important role in oxygen transport between solid phases under biased conditions. In addition, effects of ion conductivity of electrolyte on the performance of LSM-ESB are determined. Also, the high temperature reactivity between LSM and ESB solid phases is studied and the possible degradation mechanism is proposed. Our results provide insights in the oxygen transport on LSM-ESB through the comprehensive study.
Diffusion-Related SOFC Stack Degradation
Authors: Menzler Norbert H. , Beez Alexander , Grünwald Nikolas , Sebold Doris , Fang Qingping , Vaßen Robert
Published: February 2020

Solid Oxide Fuel Cell systems for stationary applications should exhibit low degradation (<< 1%/1,000h voltage loss) to ensure long-term operation (> 40,000h). The rather high operation temperature of SOFCs (≥ 700°C) is on the one hand beneficial for oxygen conduction through the ceramic-based electrolyte, but on the other hand all diffusion-related, energetically-driven mechanisms are also increased. This counts less for gas diffusion processes but is more pronounced for solid-state diffusion (surface, bulk, grain boundary). For gas diffusion processes other parameters like gas stream, individual partial pressures and partial pressure gradients are dominating.

Within two different stack tests with four-plane short stacks and their intensive post-test characterization two varying diffusion-related degradation mechanisms have been investigated. One is a short-term (~1250h) test with two different chromium evaporation protection layers on the air side metallic interconnect and frame and the other one is a long-term endurance test (~ 35,000h). For the first stack two planes were coated with a manganese oxide layer applied by wet powder spraying (WPS) while the other two planes were coated by atmospheric plasma spraying (APS) with a manganese-cobalt-iron-spinel layer. Thus the protection layers do not only differ by coating technology but also by material. The voltage loss in the planes with WPS-coated interconnect was markedly higher than in those coated by APS. Finally it turned out that the layers microstructure plays the key role in Cr evaporation minimization. In this stack, gas-phase diffusion is dominating degradation.

In the long-term operated stack, the influence of a diffusing element from the cathodic contact layer towards and through the electrolyte has been characterized. Manganese, presumably originating from the contact layer (but it’s additionally also part of the protection layer), diffuses via solid-state diffusion and reacts while reaching reducing conditions in the fuel compartment with the zirconia-based electrolyte. This interaction forms a secondary sponge-like porous phase at the boundary electrolyte-anode. This secondary phase causes stresses and leads, after growing to big islands of some ten micrometers in diameter, to electrolyte-anode delamination and finally to complete cell failure. For the Mn-related degradation solid state diffusion has been supposed, as the electrolyte is coated by a dense thin-film diffusion barrier layer which suppresses gas diffusion.

Both results indicate that volatile elements (which could either evaporate via gas phase or diffuse via solid state diffusion) should be avoided as they can lead to severe cell, stack and system failure even after thousands of hours of high-temperature operation.
Carbon-Tolerant Ni/ScCeSZ via Aqueous Tape Casting for IT- SOFCs
Authors: Arifin Nor , Button Tim , Steinberger-Wilckens Robert
Published: February 2020

Due to high temperature requirement and carbon coking of Ni/8YSZ anode, Ni/10ScCeSZ as alternative anode material is developed. Ni/8YSZ and Ni/10ScCeSZ anode supported cells were fabricated in-house using multilayer aqueous tape casting method. To enhance the tolerance towards carbon deposition, Tin was introduced as dopant. The performances of the cells were tested using hydrogen and dry biogas at 700°C, 750°C and 800°C. The result from conductivity test at 600-850°C shows that the conductivity of 10ScCeSZ is higher than 8YSZ as expected. The conductivity test was performed using Van der Pauw method. From the electrochemical and impedance test, the open circuit voltage (OCV), maximum power densities, ohmic resistance and polarization resistance are compared. The test rig is connected to the mass spectroscopy to assist the understanding of the reaction inside the rig. Microstructure images are characterized using Scanning Electron Microscopy (SEM). With the result of this work, it gives brighter possibility of using biogas as fuel in the SOFC.
A Direct Methane Fuel Cell with Double-Layered Electrolyte Using Proton Conducting Oxide
Authors: Okuyama Yuji , Kawano Shigemichi , Sakai Go , Matsunaga Naoki , Mizutani Yasunobu
Published: February 2020

BaCe0.8Y0.2O3-δ (BCY) have high proton conductivity, but are less stable against carbon dioxide. La0.9Sr0.1Yb0.8In0.2O3-δ (LSYbIn) have chemical stability, but are not so conductivity as BCY. In this study, the performance of methane fuel cell using BCY and LSYbIn as electrolyte have been studied. The fuel cell using BCY showed the short-term degradation. On the other hand, the fuel cell using LSYbIn showed the high capability in methane.The protonic ceramic fuel cell with double-layered electrolyte was developed to improvement of the chemical stability with methane and the fuel cell performance. LSYbIn was used as fuel side intermediate layer of fuel cell using BCY for protective with methane. The fuel cell with double-layered electrolyte suppressed the degradation by methane.
Low-Temperature Chromium Poisoning of SOFC Cathode
Authors: Heo Su Jeong , Hu Boxun , Aphale Ashish N , Uddin Md Aman , Singh Prabhakar
Published: February 2020

Low-Temperature Solid Oxide Fuel Cells (LT-SOFCs), operating in 500-700 °C temperature range on fossil derived hydrocarbon fuels, are widely viewed as the “next generation” of clean and efficient electrochemical power generation technology that may also remain prone to gaseous chromium assisted cathode poisoning. Chromium poisoning of strontium doped lanthanum manganite (LSM) and lanthanum strontium cobalt ferrite (LSCF) cathodes have been studied in half-cell configuration at 650 °C in gaseous chromium vapor containing humidified air. The electrochemical performance of LSM/YSZ/Pt half-cell shows faster degradation in chromium containing air with a rapid change in the polarization resistance compared to LSCF/GDC/Pt half-cell. Electrode chemistry, morphology and elemental distribution have been studied using Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray Analysis (EDX) and X-ray Diffraction (XRD) techniques. A thermodynamic analysis of the degradation process was also conducted. Our observations show that lowering of cell operating temperature may not significantly lower the cell performance degradation. Possible approaches for mitigating above degradation will be discussed.
New Applications of SOFC-MGT Hybrid Power Generation System for Low-Carbon Society
Authors: Kawabata Yasuharu , Tachikawa Yuya , Taniguchi Shunsuke , Matsuzaki Yoshio , Sasaki Kazunari
Published: February 2020

SOFC and micro gas turbine (MGT) hybrid power generation system in Fig.1 (a) is expected as a solution for energy saving and less CO2 emission. High temperature pressure swing absorption (HT-PSA) in Fig.1 (b) is also expected as an efficient method for pure O2 production.

Applying HT-PSA to the pressurized high-temperature cathode off-gas of SOFC-MGT hybrid system, we are able to obtain pure O2 more efficiently than the other conventional method.

Using obtained O2 for anode off-gas oxidation, we can easily capture CO2, which leads to effective carbon-less or negative-carbon solution. Produced O2 are also useful for efficient gasification, which leads to CO2-capture IGFC system.

In this study, we performed basic performance tests of SOFC-MGT and HT-PSA systems. Using these results, we also studied expecting performance and technical issues of proposed SOFC application systems.

Acknowledgements

This research is supported by The Japan Science and Technology Agency (JST) through its “Center of Innovation Science and Technology based Radical Innovation and Entrepreneurship Program (COI Program)" and Mitsubishi Hitachi Power Systems(MHPS) Co., Ltd.

Figure 1
In Situ Battery Spectroscopy: A Novel Approach to Investigate Unmodified Working Batteries
Authors: Sorte Eric Glenn , Tong YuYe Jay , Alam Todd M
Published: February 2020

We develop a new system and capability for performing in situ electrochemical nuclear magnetic resonance (EC-NMR) spectroscopy on batteries with the aim to measure spectroscopic data during battery cycling. In traditional battery NMR, the battery under investigation is placed inside a solenoid coil. The metal battery electrodes, essential to the battery operation, are necessarily also placed inside the coil, which lowers the sensitivity and resolution of the resulting data. In the case of electrodes that are thick compared to the radiofrequency skin depth at the NMR frequency, in situ NMR may be impossible. In that case, the rf field is effectively screened by the metal electrodes and is prevented from imparting the magnetic energy necessary for NMR to the interior of the battery. Our system, in contrast, uses an internal stripline detector. The essential 2-dimensional stripline detector is built into the battery itself during fabrication, and allows high quality NMR data to be obtained in situ during battery operation regardless of the thickness of the electrodes. Initial 7Li NMR results on pouch cell batteries with a variety of cathode materials (LiFePO4, LiCoO2, and LiNi5Mg3Co2O2) versus a graphite anode are discussed. The EC-NMR system can be used to study any NMR active nucleus of interest and so is versatile in studying a variety of battery types. This technique has the potential to allow investigation of many poorly-understood battery chemistries, and provides the means to monitor the creation and consumption of chemical species during actual battery operation conditions.

Sandia National Laboratories is a multi-mission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC., a wholly owned subsidiary of Honeywell International, Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525. This work was funded by the Sandia Exploratory Express LDRD program.
Inner-Constructed Growth Approach to Fabricate Integrated Chemical Vapor Deposition-Grown Graphene/Ni(OH)2/Ni Foam As an Advanced Electrode for Supercapacitors
Authors: Liu Shude , Jun Seong Chan , Hui Kwun Nam
Published: February 2020

Nickel hydroxide is considered to be a potential electrode material for supercapacitors owing to its high theoretical capacity. However, its poor inherent electrical conductivity results in severe capacity fading and inferior cycling stability during the continuous charge/discharge process. Herein, we propose an approach to fabricate a compact, robust, and integrated chemical vapor deposition (CVD) graphene (G)/Ni(OH)2/nickel foam (NF) electrode using an inner-constructed growth strategy in which Ni(OH)2 nanosheets were grown on NF by a hydrothermal reaction via the fractures on CVD graphene intentionally created through ultrasonication. The resultant G/Ni(OH)2/NF enables Ni(OH)2 to possess high electrical conductivity for efficient electron transport and suppresses the structural deformation of Ni(OH)2 nanosheet arrays. The unique architecture boosts the electrochemical performance of Ni(OH)2 to its theoretical limit with a high specific capacity of 991 C g−1 at a current density of 1 A g−1, good rate capability, and excellent cycling stability, retaining 95.4% of the initial capacity after 5000 cycles. Moreover, an asymmetrical supercapacitor (ASC) was fabricated using G/Ni(OH)2/NF and activated carbon (AC) coated on NF as the positive and negative electrodes, respectively. The ASC device operating at a cell voltage of 1.45 V delivered an energy density of 50.3 W h kg−1 at a power density of 725 W kg−1 in addition to achieving good cycling stability with a capacitance retention of 84.3% after 10000 cycles at a current density of 10 A g−1.