bluuebunny/crossref_metadata_2025_split huggingface dataset:
Solid Oxide Fuel Cell, Stack and System Development Status at Forschungszentrum Jülich
Authors: Blum Ludger , Batfalsky Peter , Fang Qingping , de Haart L.G.J. , Malzbender Jürgen , Margaritis Nikolaos , Menzler Norbert H. , Peters Roland 
Published: February 2020

Based on more than 20 years SOFC scientific development, JÜLICH is still continuously improving its technology. Utilizing the proprietary cell manufacturing technology of warm pressing of the anode substrate cells of the dimension 20x20 cm² have been manufactured and tested in various stack sizes with power outputs of up to 5 kW, of which four were operated in a 20 kW system. It was demonstrated in a 1 kW stack that cells of this size can also be successfully operated using tape casted substrates. In parallel to the cell development the stack design was improved aiming at enhanced thermo-mechanical robustness. Thereby a stack in the kW range could be cycled successfully 100 times between 200 and 700°C. To be able to integrate also cells from other manufacturers the design was shifted to a picture frame layout, incorporating currently four 10x10 cm² cells in one layer, a larger number of cells is still optional. First successfully operated stacks showed a comparable performance to short stacks with one 10x10 cm² cell.
The 20 kW system set into operation in 2012 was operated for about 7000 h in total proofing thereby the suitability of the module and system concept developed in JÜLICH.
As special highlights, the long-term tests with short stacks have now reached under continuous operation at 700 °C and 0.5 Acm-² times of 63,000 h (degradation 0.7%/kh, 0.3%/kh in the last 25,000h) and 33,500 h (degradation 0.3%/kh), respectively.
Theoretical Analysis of Cation Diffusion Pathway in SOFC Interlayer
Authors: Lin Ching-Tang , Ishimoto Takayoshi , Koyama Michihisa 
Published: February 2020

Cation diffusions in solid oxide fuel cell (SOFC) interface can cause some degradations. For instance, the effect that gadolinium-doped ceria (GDC) interlayer on the cathode prevent degradation of the SOFC cathode, and its degradation during current load cycling was investigated (1). Additionally, when (LSCF) is used as cathode, Sr diffuses from the cathode to electrolyte through GDC interlayer and then insulating materials precipitates on the electrolyte. It is necessary to raise the temperature immediately or use large-scale experimental devices such as neutron diffraction device or accelerator (2) to trace cation diffusion pathway. By using molecular dynamics simulation (MD), diffusion pathway of oxygen ion is elucidated. However, in the time scale of MD simulation the structural and chemical transformations involving the breaking and formation of bonds are rare events (3). It is caused by the difference of jump probabilities. Thus, to accelerate the diffusion of cation, metadynamics method which adds history-dependent bias potential constructed by summing Gaussian-shaped is used (4). In this work, LSCF cathode, GDC interlayer and yttria stabilized zirconia (YSZ) electrolyte are modeled to simulate to trace cation diffusion pathway in SOFC interface.

References

M. Z. Khan, R. H. Song, S. B. Lee, J. W. Lee, T. H. Lim, S. J. Park, Int. J. Hydrogen Energy, 39,20799 (2014)

K. Fuzii, Y. Esaki, K. Omoto, M. Yashima, A. Hoshikawa, T. Ishigaki, J. R. Hester, Chem. Mater., 26, 2488(2014)

J. Kiss, T. Gruhn, G. Roma, C. Felser, J. Phys. Chem. C, 117, 25933 (2013)

U. Aschauer, P. Bowen, S. C. Parker, Acta Materialia, 57, 4765 (2009)
LSGM-based Cells for IT-SOFC Applications
Authors: Mercadelli Elisa , Sanson Alessandra , Gondolini Angela , Pinasco Paola , Basoli Francesco , Di Bartolomeo Elisabetta 
Published: February 2020

Solid Oxide Fuel Cells have still many technical problems related to its high operating temperature (800–1000 °C). The most recent studies deal with reducing the operation temperature increasing at the same time the durability of the device. The use of La0.8Sr0.2Ga0.8Mg0.2O3-δ(LSGM) perovskite as electrolyte, could be a very promising solution for IT-SOFC operating at 600°C. In this work, LSGM bilayers constituted by a thicker porous layer (namely the anode scaffold) and a dense electrolyte were produce by co-firing using two different techniques: i) die-pressing + spin coating, ii) tape casting + lamination. In both cases the nature and amount of pore former needed to obtained an anode scaffold with a porous network suitable for the Ni impregnation process were deeply investigated.
In the die-pressing + spin coating method, supporting anodes were prepared pressing LSGM commercial powder with a proper amount of binder and a tailored mixture of pore forming agents. Onto the pre-sintered anode support, an electrolyte layer was deposited by spin coating. In the tape casting + lamination route, the starting ceramic suspensions with and without pore formers were carefully optimized to produce the anodic and electrolytic green tape respectively, while the lamination parameters, in terms of temperature, time and pressure, were adjusted to obtain defect-free bilayers. The sintering conditions were also optimized in order to achieve the best compromise in terms of density of the electrolyte and porosity of the anode scaffold.
Structural and morphological characterizations of the produced bilayers as well as the electrochemical performances of the cells in the temperature range 600-750°C will be reported. The potentialities and disadvantages of the two processing approaches will be thoroughly discussed.
Methane Synthesis Characteristics of H2O/CO2 Co-Electrolysis in Tubular Solid Oxide Electrolysis Cells
Authors: Luo Yu , Li Wenying , Shi Yixiang , Ye Xiaofeng , Wang Shaorong , Cai Ningsheng 
Published: February 2020

Producing methane by H2O/CO2 co-electrolysis through solid oxide electrolysis cell (SOEC) is a promising method to store unstable renewable power and reduce CO2 emission simultaneously. Theoretically, methanation reaction is possible to happen in standard condition when temperature is lower than 600oC. Tubular solid oxide electrolysis cell (TSOEC) has great potential for large-scale application due to easily sealing and high strength. Moreover, gradient distribution of temperature in flow direction is beneficial to CH4 production. In this paper, CH4 synthesis characteristics in TSOEC is studied in the temperature range of 500-650oC by combining experiment and simulation. Experiment demonstrates the addition of H2 increases the outlet molar fraction of CH4 from 0 to 2.85% at 600oC, and from 0.01% to 8.77% at 550oC. In addition, it’s found that electricity significantly promotes CH4 production, especially when H2 is added. The applied voltage of 1.5V just increases CH4 production ratio by <0.04% in the absence of H2. But when 20% H2 is fed in cathode, CH4 production ratio is improved by 3-4%. Finally, the optimal operating condition, thermal distribution and reaction active zones are simulated by a well validated thermal model. The thermal distribution can be changed by outer boundary condition. CH4production can be further improved by increasing the temperature of upstream zone and reducing that of downstream zone.

Fig.1
Methane synthesis schematic in TSOEC

Figure 1
Role of Hole Doping on the Oxygen Vacancy Formation and Migration in LaCoO3
Authors: Salawu Omotayo akande , Gan Liyong , Schwingenschlogl Udo 
Published: February 2020

The LaCoO3 class of materials is of interest for cathodes of solid oxide fuel cells. Spin-polarized
density functional theory is applied to cubic La0.75 (Mg/Ca/Ba)0.25 CoO3 . The effect of this cation
doping on the electronic and magnetic properties as well as oxygen vacancy formation energy is
studied. Oxygen vacancies with proximity to the dopant are energetically favourable in most cases.
We discuss the effect of distortions of the CoO6 octahedron on the electronic structure and the
formation energy of oxygen vacancies. The order of formation oxygen is found to be Mg > Ca >
Ba. Cation doping incorporates holes to the Co-O network which enhances the oxygen vacancy and migration.
Lithium-Rich Core-Shell Cathodes with Low Irreversible Capacity and Mitigated Voltage Fade
Authors: Li Jing , Camardese John , Shunmugasundaram Ramesh , Glazier Stephen , Lu Zhonghua , Dahn Jeff R 
Published: February 2020

Lithium-rich layered Ni-Mn-Co oxide materials have been intensely studied in the last decade. Mn-rich materials have serious voltage fade issues and the Ni-rich materials have poor thermal stability and readily oxidize the organic carbonate-based electrolyte.1 Core-shell (CS) strategies that use Ni-rich material as the core and Mn-rich materials as the shell can balance the pros and cons of these materials in a hybrid system.2 The lithium-rich CS materials synthesized through co-precipitation method introduced here showed much improved overall electrochemical performance compared to the core-only (Ni-rich) and shell-only (Mn-rich) samples.
In this work, CS samples with 67 mol% of core with the composition Li1+x(Ni0.67Mn0.33)1-xO2 (C) and 33 mol% of shell with the compositions Li1+x(Ni0.2Mn0.6Co0.2)1-xO2 (S1) or Li1+x(Ni0.4Mn0.5Co0.1)1-xO2 (S2) with varied lithium content were synthesized and studied.
Figure 1 shows the energy dispersive spectroscopy results of the CS precursor and lithiated samples. Figure 1 shows that there was diffusion of transition metals between the core and shell phases after sintering at 900oC compared to the prepared hydroxide precursors. A Mn-rich shell was still maintained whereas the Co which was only in the shell in the precursor was approximately homogeneous throughout the particles.
The CS samples with optimal lithium content showed low irreversible capacity (IRC), as well as high capacity and excellent capacity retention. Sample CS2-3 had a reversible capacity of ~218 mAh/g with 12.3% (~30 mAh/g) IRC and 98% capacity retention after 40 cycles to 4.6 V at 30oC at a rate of ~C/20.
Figure 2 shows the average discharge potential (a) and the difference between the average charge and discharge potentials, delta V (b), of cells with the core-only (C), CS and shell-only (S) samples. Figure 2 shows that cells of the CS samples have stable impedance (delta V is stable) as well as a very stable average voltage as compared to cells of the core-only and shell-only samples. Ultra-high precision coulometry (UHPC) measurements confirmed that the CS samples with optimal lithium content had distinctively better columbic efficiency.
Apparently, the Mn-rich shell can effectively protect the Ni-rich core from reactions with the electrolyte while the Ni-rich core renders a high and stable average voltage.

Reference

1. E.-J. Lee, H.-J. Noh, C. S. Yoon, and Y.-K. Sun, J. Power Sources, 273, 663–669 (2015).
2. J. Camardese, J. Li, D. W. Abarbanel, a. T. B. Wright, and J. R. Dahn, J. Electrochem. Soc., 162, A269–A277 (2014).

Figure 1
Effects of K-Ion Doping on Electrochemical Performance of Na3V2(PO4)3 Cathode Materials for Na-Ion Batteries
Authors: Eom Ji-Yong 
Published: February 2020

Lithium ion batteries have been widely studied due to their superior energy and power densities to utilize large scale applications such as electric vehicles and energy storage systems. In spite of extensive researches to overcome the problem of the lithium ion battery price, the large scale battery market has been sluggishly extended primarily due to the lack of lithium resources. Alternatively, sodium ion batteries are illuminated for the energy sources of the large scale energy storage system because of sufficient sodium sources.
As a class of the sodium ion battery cathode materials, phosphate-based Na-insertion hosts (NaVPO4F, NaMPO4, Na1.5VOPO4F0.5, Na2FePO4F, NaTi2(PO4)3, etc.) with strong polyanion networks have received great attention due to their excellent structural and thermal stabilities. NASICON-Na3V2(PO4)3 is the one of the promising cathode materials for the sodium ion batteries. Na3V2(PO4)3 shows 117.6 mAh·g-1 theoretical capacity at 3.4 V vs. Na/Na+ in V4+/V3+ redox couple. It has strong PO4 polyanion networks which improve the safety of the large scale applications. Unfortunately, Na3V2(PO4)3 shows severe capacity fading at high rate because of the low electrical conductivity and ion diffusivity. In the phosphate-based active materials for Li or Na ion batteries, the addition of conductive materials and the substitution of transition metal or alkali metal with alien ions have been conducted to overcome these problems. Especially the substitution of Li ion with Na ion or K ion for the Li ion batteries shows better electrochemical performances due to the lattice expansion and narrowing the band gap.
In this work, NASICON-Na3-xKxV2(PO4)3/C (x=0, 0.05, 0.10, and 0.15) are synthesized by a solid state reaction. By the doped K ion which is larger than Na ion (rK+ (1.52 Å) > rNa+ (1.16 Å)), the structure becomes enlarged and it makes Na ion migrate easily. Moreover the doped K ion in the structure even after charging contributes to the structural stability by reducing volume changes during cycling.
Conductivity Enhancement and Thin-Film Processing of Li4Ti5O12(LTO) Spinel for Li Battery Applications
Authors: Tsai Shu-Yi , Fung Kuan-Zong , Ni Chung-Ta 
Published: February 2020

Lithium titanium oxide spinel Li4Ti5O12 has been reported to be a zero-strain lithium insertion host material because it exhibits extremely small variations of the lattice parameters during the charge and discharge processes. In general, Poor adhesion between thin-film electrode and substrates is the common cause for performance degradation of thin-film electrode during repeated charge/discharge tests. Thus, Li4Ti5O12 spinel may be the ideal candidate for the anode of thin-film Li ion battery for long cycle applications.
However, unmodified Li4Ti5O12 usually exhibits poor rate performance, which mainly results from its low electronic conductivity (ca. 10-13 S·cm-1) and moderate Li+ diffusion coefficient (10-8cm2·s-1).
In addition, different electrochemical behaviors will be expected when Li4Ti5O12 spinel is prepared in thin-film compared to that in power forms. Therefore, the objective of this work is (1) to enhance the conductivity of Li4Ti5O12 spinel by substitution of aliovalent dopants for Ti ions, (2) to fabricate thin film of Li4Ti5O12spinel by using RF-sputtering technique, (2) to investigate the effect of annealing temperature/atmospheres on the electrical/electrochemical properties of thin film Li4Ti5O12, (3) to evaluate the feasibility of using thin film of Li4Ti5O12 as anode for Li microbattery applications.
In this study, the Li4Ti5O12 thin film was deposited on either the Si substrate or glass substrate by sputtering technique. The crystallization of deposited Li4Ti5O12 thin film will be enhanced by annealing at various atmospheres and temperatures. The single phase Li4Ti5O12 was finally obtained after co-sputtering of Li-containg and Ti-containing targets. The crystal structure and crystallization will be examined by glancing XRD. The resistivity of Li4Ti5O12 thin film will be evaluated by four probe technique and our novel micromeaurement system. The capacity of Li4Ti5O12 thin film will be evaluated from charge/discharge tests.
A Comparative Study of Layered Transition Metal Oxide Cathodes for Application in Sodium-Ion Battery
Authors: Hasa Ivana , Buchholz Daniel , Passerini Stefano , Hassoun Jusef 
Published: February 2020

Nowadays, efficient, safe, low cost and environmentally friendly storage systems are required in response to the modern society needs. Li-ion batteries (LIBs), considered one of the promising systems to fulfill these requirements, represent the most widespread secondary battery for consumer and portable electronics and possibly for power hybrid and electric vehicles.[1] Stationary energy storage, in contrast to high energy density applications, is principally driven by cost rather than high performances in terms of energy density. Therefore, batteries with alternative chemistry, complementary to and not competing with the lithium-ion battery technology are necessary.[2,3]
Recently, sodium-ion batteries have attracted large attention since, in principle, suitable to match the economic and environmental issues due to the high abundance and low cost of the employed materials.[4,5]Herein, we report a study on P-type layered sodium transition metal-based oxides, of the composition NaxMO2 (M=Ni, Fe, Mn), used as cathode materials for sodium-ion batteries employing a 1M NaPF6 in propylene carbonate (PC) as electrolyte solution.[6] Indeed, P-type layered oxides appear to be very promising in terms of high delivered capacity. [7,8] We synthesize the materials via co-precipitation method followed by an annealing step in air and a water rinsing process. Following, we fully investigate the effect of Ni to Fe ratio, annealing temperature and sodium content on the electrochemical performances of the electrodes. The impact of these parameters on the structural and electrochemical properties of the materials is revealed by X-ray diffraction, scanning electron microscopy and cyclic voltammetry, respectively. The suitability of this class of P-type materials for sodium battery application is finally demonstrated by cycling tests revealing an excellent electrochemical performance, with a delivered capacity of about 200 mA h g-1and charge-discharge efficiency approaching 100 %.
[1] J.-M. Tarascon, M. Armand, Nature,414, 359 (2001);
[2] J.-M. Tarascon, Nat. Chem., 2, 510 (2010) ;

[3] B. W. Jaskula , Lithium, in Mineral Commodity Summaries 2012 , U. S. Geological Survey , Reston, VA 2012 , p. 94;
[4] V. Palomares, P. Serras, I. Villaluenga, K.B. Hueso, J. Carretero-Gonzalez, T. Rojo, Energy Environ. Sci., 5, 5884 (2012);
[5] S.-W. Kim, D.-H. Seo, X. Ma, G. Ceder, K. Kang, Adv. Energy Mater., 2, 710 (2012);
[6] I. Hasa, D. Buchholz, S. Passerini, J. Hassoun, ACS Appl. Mater. Inte., (2015) in press;

[7] I. Hasa, D. Buchholz, S. Passerini, B. Scrosati, J. Hassoun, Adv. Energy Mater. 2014, doi:10.1002/aenm.201400083;

[8] N. Yabuuchi, M. Kajiyama, J. Iwatate, H. Nishikawa, S. Hitomi, R. Okuyama, R. Usui,Y. Yamada, S. Komaba, Nature Mater., 11, 512 (2012);

Figure 1
Iron Doping Effects in NiMn2O4 Structures with Hierarchical Porosity: Stabilization of the Cubic Spinel Phase and Kinetics Activation for Li Storage
Authors: Ma Yue , Tai Cheuk-Wai 
Published: February 2020

Spinel-type mixed oxides possess richer redox reactions for Li+ storage and at least two orders of magnitude higher electrical conductivity than binary metal oxides. This talk demonstrates the synthesis of NiMn2O4 composite with three-dimensional macro/mesoporous network and various iron doping amount via a facile and scalable nanocasting method. Multi-scale pores were integrated in the structure through the structural engineering: interconnected macropores were reverse-replicated by employing the polymeric sacrificial template; whereas mesopores were formed upon the pyrolysis of the polymer during heat treatment. Through tailoring the metal precursor ratio, the tetragonal sites of divalent nickel could be preferentially substituted by iron, resulted in the stabilized cubic phase of quaternary oxide FexNi1-xMn2O4. Combining the elemental analysis from XPS and EELS techniques as well as crystal field theory, we concluded the stabilization mechanism of iron doping in our spinel structure system. Electrochemical characterizations exhibited the best of the composites prepared as such was capable to deliver high specific capacity, remarkable rate capability (2 A.g-1) and very good cycle life for Li+ storage (600 cycles).
The Role of Carbon on the Discharge Product and Cell Performance of the Sodium Superoxide (NaO2) Battery
Authors: Bender Conrad L. , Schwab Matthias Georg , Adelhelm Philipp , Janek Jürgen 
Published: February 2020

Batteries based on the cell reaction between alkali metals and atmospheric oxygen are highly attractive energy stores due to their superior theoretical energy densities. However, despite continuous progress fundamental challenges in further developing these cell systems remain. Understanding the oxygen electrode reaction and improving cycle life while at the same time maximizing the practical energy capacity are some of the most important issues that have to be tackled. Here, we focus on the aprotic sodium-oxygen battery and the role of the carbon electrode on product formation and cell performance (cycle life and capacity)[1-2].
Two different discharge product have recently been reported in literature for the sodium-oxygen battery, one leading to either sodium peroxide or hydrated sodium peroxide and the other to sodium superoxide. [3-8] The thermodynamic driving force is quite similar for both cases and it remains unclear whether only kinetics or also nano-effects [9] determine the reaction route. One important aim of our current study therefore was to explain the discrepancy reported in literature. [1] We investigated whether the electrode material, the structure or the local current density have any influence on the product stoichiometry or the cell performance. Therefore, we tested several types of carbon materials with a broad range in properties. As important finding, we always found phase-pure NaO2 as discharge product irrespective of the type of carbon used. But at the same time, the achievable capacities range from 300 to values as high as 4000 mAh∙g(C)-
1. We further studied the impact of electrolyte composition on the cell chemistry and found significant differences depending on the type of solvent used. At last, we demonstrate that the cycle life of Na/O2 cells can be largely improved by using carbon nanotubes based electrodes yielding capacities of 231 mAh∙g(C)-
1 / 0.64 mAh∙cm-
2 for at least 140 cycles. [2]
Acknowledgment: The research was supported by the BASF scientific network of electrochemistry and batteries. C.L. Bender is grateful to Fonds der chemischen Industrie (FCI) for a scholarship.
Literature:
[1] C.L. Bender, Adv. Energy Mater., 2014, doi: 10.1002/aenm.201301863. [2] C.L. Bender, Energy Technol., 2015, doi: 10.1002/ente.201402208 [3] Q. Sun, Electrochem. Commun., 2012, 16, 22–25. [4] W. Liu, Chem. Commun., 2013, 49,1951-1953. [5] J. Kim, Phys. Chem. Chem. Phys., 2013, 15, 3623-3629. [6] Z. Jian, J. Power Sources, 2014, 251, 466-469. [7] P. Hartmann, Nat. Mater. 2013, 12, 228-232. [8] N. Zhao, Phys. Chem. Chem. Phys., 2014, 16,15646-15652. [9] S. Kang, Nano Lett., 2014, 14, 1016- 1020.
Cathodes for Lithium Sulfur Batteries
Authors: Nitze Florian , Fossum Kjell , Andersson Simon , Xiong Shizhao , Palmqvist Anders , Matic Aleksandar 
Published: February 2020

Lithium sulfur (Li-S) batteries are a promising candidate to replace state-of-the-art lithium-ion batteries with an expected 3-5 fold increased capacity. Even though they have been studied for decades the final breakthrough to make the system feasible for application for example in the transportation sector has not yet been achieved. However, many improvements have been made during the last years. One of many obstacles that needs to be overcome is the design of suitable cathodes, efficiently preventing capacity fading.
Here, different carbon nanostructures have been tested as sulfur containing matrices in Li-S batteries. Examples are sulfur-doped ordered mesoporous carbons (S-doped OMC) or helical carbon nanofibers (HCNFs). With both materials we achieve high sulfur utilization and good capacity retention. Sulfur-doping of the carbon matrix shows positive effects on cyclability and capacity per cathode mass. We find that the doping also influences the electrochemical behavior of the whole system and conclude that there exists a strong interaction between dopant and loaded sulfur utilized during charge and discharge of the battery. In the system using helical nanofibers we find that the performance of HCNFs is substantially better compared to straight fibers or nanotubes. We explain this with the specific properties of HCNFs making activation efficient without major deterioration of the overall structure. All materials have been extensively characterized using a variety of methods such as electron microscopy and electrochemical testing.