bluuebunny/crossref_metadata_2025 huggingface dataset:
Nickel Selenide As High-Efficiency Catalyst for Oxygen Evolution Reaction
Authors: Swesi Abdurazag , Masud Jahangir , Nath Manashi
Published: February 2020

Electrolytic water splitting is considered to be clean energy generation and a substitute for fossil fuels and oxygen evolution reaction (OER) is an important reaction involved in water splitting. However, OER typically being a 4 electron process requiring O – O bond formation is a kinetically slow process typically requiring catalysts.1Identifying more-efficient, stable, earth-abundant catalysts for the OER has long been researched. Recently, Ni-oxide based OER electrocatalysts were found to exhibit high efficiency, and it was stated that the catalytic performance can be further tuned by increasing covalency in the metal-oxygen bonds. The catalytic properties of the metal oxides can also be influenced through other variables of the electrodeposition reaction such as the total and relative concentration(s) and composition(s) of dissolved metal salts and extra electrolytes, the pH, and the duration of the electrodeposition current.2 Here we report, for the first time, a metal-rich form of Ni-selenide, Nickel subselenide, Ni3Se2 as a potential oxygen evolution electrocatalyst in alkaline condition. The Ni3Se2 phase has a structure similar to the sulfur mineral Heazlewoodite, which contains metal – metal bonding. The electrocatalytic activities of Ni3Se2towards OER was seen to be at par with or even superior to the transition metal oxide based electrocatalyst in terms of onset overpotential for O2 evolution as well as overpotential to reach a current density of 10 mA/cm2 (observed at 290 mV).

The electrocatalytic Ni3Se2 were grown by electrodeposition on conducting substrates and the deposition parameters including pH of the electrolytic bath, deposition potential, and substrate composition were seen to have some influence on the catalytic activity. Annealing of the as-deposited electrocatalytic films in an inert atmosphere enhanced their catalytic efficiencies by decreasing the overpotential (@10 mA/cm2) as well increasing the current density. In addition to low overpotentials, these Ni3Se2 electrodeposited films were seen to be exceptionally stable under conditions of continuous O2 evolution for extended period (48 – 66 h). The structure and morphology of these films has been characterized with powder X-ray diffraction, Scanning and Transmission electron microscopy, Raman, and X-ray photoelectron spectroscopy. We will discuss in detail the electrochemical and structural characterizations of these films along with catalytic activities.  

References:

1. E. Mirzakulova, R. Khatmullin, J. Walpita, T. Corrigan, N. M. Vargas-Barbosa, S. Vyas, S. Oottikkal, S. F. Manzer, C. M. Hadad, and K. D. Glusac, Nature Chem. 2012, 4, 794.

2 McCrory, C. C. L.; Jung, S. H.; Peters, J. C.; Jaramillo, T. F. J. Am. Chem. Soc. 2013, 135, 16977.
Combined Experimental and Computational Approach for Rational Design of Bio-Nano Interfaces
Authors: Babanova Sofia , Matanovic Ivana , Chavez Madelaine Seow , Atanassov Plamen
Published: February 2020

Various approaches have been developed in the last 5 years regarding targeted enzyme orientation on the electrode surface but no explanation of enzyme orientation on electron transfer properties have been provided. The same can be said about the utilization of mediators for enhancement of the interfacial electron transfer. Facing this fundamental challenge we started using computational approaches along with experimental efforts to gain knowledge of the underlying processes.

In our computational and experimental benchmark studies soluble PQQ-dependent glucose dehydrogenase (PQQ-sGDH) have been explored since this enzyme is known as capable of direct electron transfer (DET). Various techniques for PQQ-sGDH immobilization and/or enhanced electron transfer have been developed over the years and a key question regarding the “proper” orientation of PQQ-sGDH has been raised. Should the substrate-binding pocket and thus PQQ be placed facing the electrode surface or it should be fully exposed to the electrolyte?

To resolve this question and to enhance the electron transfer at the enzyme-electrode interface, quinones were explored in solution and immobilized on carbon support material. In both cases the current densities generated form the glucose oxidation through PQQ-sGDH were increased from 1.5 to 5 times depending on the properties of the explored quinones. In addition to the electrochemical characterization of the designed enzymatic anodes, molecular computational calculations, such as Density Functional Theory (DFT) and Molecular Docking Simulations, were used to gain insight into interactions between the quinones and PQQ-sGDH from one hand and the quinones and the support material, from another (Fig. 1). The role of the two types of benzoquinones, 1,2- and 1,4-benzoquinone, and ubiquinone in the operation and mechanism of the electron transfer in PQQ-sGDH anodes has been addressed1.

It was established that the higher electrochemical performance of PQQ-sGDH anodes in the presence of free 1,2- and 1,4-benzoquinones is due to the smaller distance between these molecules and the enzyme cofactor (PQQ). It was proposed that when 1,4-benzoquinone is adsorbed, it plays the role of a mediator as a result of its high electron transfer rate ability and smaller PQQ-quinone distance. At the same time when 1,2-benzoquinone is adsorbed on the electrode surface, the enzyme will transfer the electrons directly to the support and the modifier will mostly play the role of an orienting agent. Similar conclusion can be made for the PQQ-sGDH anode modified with physically adsorbed ubiquinone for which purely orientation role was proposed.

1.Babanova, S., Matanovic, I. & Atanassov, P. Quinone-modified surfaces for enhanced enzyme-electrode interactions in PQQ-dependent glucose dehydrogenase anodes. Chem. Electro. Chem.
1, 2017–2028 (2014).

Figure 1
Electrochemical Investigations of Aromatic Hydrocarbons in Adiponitrile
Authors: Cheek Graham T.
Published: February 2020

Introduction

     Recent work from this laboratory has shown that adiponitrile (NCCH2CH2CH2CH2CN) / tetraethylammonium tetrafluoroborate (TEA BF4) is a versatile solvent system for organic electrochemistry (1,2).  The extraordinary 7-Volt potential range noted in earlier work (3) has been confirmed and applied to measurement of water (1) and electrodeposition of metals (4).  The +5 V vs Ag/AgCl potential limit allows another 2 volts for study, compared to that of most other solvents.  The present paper addresses the usefulness of the positive potential region for oxidation of aromatic hydrocarbons.

Experimental

     Adiponitrile was purchased from Sigma-Aldrich, and tetraethylammonium tetrafluoroborate was purchased from Southwestern Analytical Chemicals.  Cyclic voltammograms were obtained on a PAR 283 potentiostat using PowerSuiteTMsoftware.  Potentials are referenced against a Ag/AgCl reference electrode (1).

 Results and Discussion

     A cyclic voltammogram of 10 mM naphthalene in adiponitrile / 0.2 M TEA BF4 is shown in Figure 1.  The reversible reduction of naphthalene is observed at -2.5 V, followed by an irreversible oxidation process at +1.74 V vs Ag/AgCl.  Scan reversal at +2.00 V shows no reduction current associated with this oxidation process at 100 mV/s.  Continuation of the potential scan to +5.0 V, as shown, results in considerable oxidation current up to the positive potential limit. This charge passage, however, significantly lessens the peak currents for the redox process at -2.5 V on the following sweep, implying some electrode filming in the highly positive potential range. Naphthalene oxidation has also been studied in acetonitrile (5), and the results were similar to those in the present study although the positive scan limit in acetonitrile was only +1.75 V vs SCE. In the acetonitrile study (5), the irreversible nature of naphthalene oxidation was attributed to rapid coupling of naphthalene radical cations.  The results of the present study show that the entire positive potential range in adiponitrile is available for study of the representative aromatic hydrocarbon naphthalene.  It is also intended to present results for other aromatic systems.  

References

1.  G. T. Cheek, ECS Trans., 58(46), 45-51 (2014).

2.  G. T. Cheek, ECS Trans., 61(30), 19-24 (2014).          

3.  H. Duncan, N. Salem, and Y. Abu-Lebdeh, J. Electrochem. Soc., 160(6), A838-A848.

4.  G. T. Cheek, ECS Trans., 61(24), 9-14 (2014).  

5.  M. N. Cortona, N. Vettorazzi, J. J. Silber, and L. Sereno, J. Electroanal. Chem., 394, 245-251 (1995).

Figure 1.  Cyclic voltammogram of 10 mM naphthalene at glassy carbon in adiponitrile / 0.2 M tetraethylammonium tetrafluoroborate.

               Initial negative-going sweep from 0.00 V vs Ag/AgCl; 100 mV/s

Figure 1
Organized Light Harvesting Photosystem I Layers on a Cytochrome C for the Construction of New Photobioelectrodes
Authors: Feifel Sven Christian , Stieger Kai , Lokstein Heiko , Lisdat Fred
Published: February 2020

Artificial approaches to mimick natural photosynthesis are an emerging field of research with impact on photobiocatalytic systems and photobiovoltaic applications. Herein, we manage the assembly of two heterologous proteins exhibiting key features for the usage in biohybrid light-converting electrode systems. We combine the photon converting pigment-protein super-complex - photosystem I (PSI), from natural photosynthesis of cyanobacteria1 - with a small electron carrier, cytochrome c (cyt c) from the respiratory chain, in mono- and multilayer arrangements. Often, PSI has a random orientation when self-assembled on surfaces and provides a slow direct electron transfer (DET).2 Our strategy to overcome these issues, is to assemble PSI with the help of electron carriers similar to native electron transport. This provides two advantages: (1) redox protein mediated indirect electron transfer (IET) may yield high photocurrents, due to rather small electron tunneling distances; (2) redox proteins can be considered as an assembly template on which PSI can adsorb efficiently by reason of electrostatic and/or native affinity, which has been studied by surface plasmon resonance (SPR). By this approach, we developed photoreactive protein layers on electrodes, which have a potential-driven cathodic photocurrent to reduce the PSI after light induced electron-hole-pair separation. The study determines the role of cyt c in such organised films, which works as a template but also show the ability to connect and wire the PSI with the electrode.3 This is also valid in a multilayer arrangement with PSI far away from the electrode surface. The system can be seen as a network with electron conducting elements forming a protein 3D architecture. In order to increase the photocurrent of such electrodes, a multilayer approach and a time-dependend self-growth of cyt c/PSI-architectures was developed. The presented work can be considered as a contribution to current research in order to develop organised protein films for the effective conversion of light into electrical and/or chemical energy.

(1) Grotjohann, I.; Fromme, P. Photosynth. Res. 2005, 85 (1), 51−72.

(2) Ciesielski, P. N. et al. J. Phys.
Chem. A
115, 3326–34 (2011).

(3) Stieger, K. R.; Feifel, S. C. et al. Phys. Chem. Chem. Phys. 16, 15667-15674 (2014).
Modified Electrodes Obtained By Electrochemical Codeposition of Some Conducting Polymers and Carbon Nanotubes with Different Dopants
Authors: Branzoi Florina , Branzoi Viorel , Pacuretu Catalina
Published: February 2020

Nanoporous composite films of functionalized single-walled carbon nanotubes (SWANTs) and (3, 4 –ethylene dioxythiophene) (PEDOT), 1-aminofenol and 3 methyltiophen with different dopants (anionic surfactants) were grown electrochemically from 0.1M LiClO4 aqueous solutions such that constituents were deposited simultaneously onto substrate electrodes. Scanning electron microscopy (SEM) revealed that the composite films consisted of nanoporous networks of SWANTs coated with polymeric film. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) demonstrated that these composite films had similar electrochemical response rates to pure polymeric films but a lower resistance and much improved mechanical integrity. The synthetic, morphological and electrochemical properties of nanocomposite materials type PEDOT/ FCNTs / dopants were compared. The negatively charged carbon nanotubes (CNTs) served as anionic dopant during the electropolymerization to synthesize polymer/CNTs composite films. Conducting polymers can be doped and dedoped rapidly to high charge density and as a result are potential active materials for use in various electrochemical applications. Thus an important application is the fabrication of modified electrodes. The specific electrochemical capacitance of the composite films is a significantly greater value than that for pure polymer films prepared similarly. Using these composite films, the modified electrodes with improved properties were obtained.
Thermal Stability Studies in Charged Layered Sodium Transition Metal Oxide Cathode Materials for Na-Ion Batteries
Authors: Bak Seong-Min , Zhou Yongning , Hu Enyuan , Yu Xiqian , Yang Xiao-Qing
Published: February 2020

Layered alkali transition metal oxides (i.e., LiMO2 and NaMO2, M=transition metal) are the premier class of cathode materials in lithium- and sodium-ion battery system. The safety characteristics of LiMO2 cathode based LIBs are one of the most critical barriers to be overcome for the large scale application such as EV. One of the main reasons that might cause safety hazards of the LIB is associated with the thermal instability of charged Li1-xMO2 cathode materials, which is related to the occurrence of exothermic reactions between flammable electrolyte and liberating oxygen from charged Li1-xMO2 at high temperature. Based on the structural homology between the layered LiMO2 and NaMO2, we expect that the investigation of thermal stability of charged Na1-xMO2cathode materials is also important for the practical use of SIBs. However, few attentions have been paid on safety issue of SIBs.

 In this study, the thermal stability of charged Na1-xMO2 cathode materials is investigated by using combined in situ time-resolved X-ray diffraction and mass spectroscopy (TR-XRD/MS), which allows simultaneous observation of the structural changes and gas species that are evolved during thermal decomposition of charged cathode materials, especially O2 gas in our interest. In addition, the ex situ/in situ X-ray absorption spectroscopy (XAS) has been also utilized to look at the local and electronic structural changes occurring during thermal decomposition in an elemental selective way. By utilizing combined X-ray techniques, we are able to get better understanding of structural and electronic structure changes in charged cathode materials during thermal decomposition. In this presentation, the thermal decomposition behavior of charged Na1-xMO2(M=Co, Cr) cathodes will be covered.

Acknowledgement

The work done at Brookhaven National Lab. was supported by the Assistant Secretary for Energy Efficiency and Renewable Energy, Office of Vehicle Technologies of the U.S. DOE under Contract No. DE-SC0012704.
3D-Nanostructures-Path to High Capacity Lithium Batteries with Ultimate Safety
Authors: Prochazka Jan , Stary Radomir , Pavlik Jiri , Zukalova Marketa
Published: February 2020

Thin film technologies (2D) producing lithium ion accumulators have nearly been optimized. The capacity limits are given by the thickness of the components, especially the foils and separators.

A significant increase of lithium battery capacity is achievable by nanostructured morphologies of the electrodes and extending of the electrode thickness from micrometers (2D) to millimeters (3D).

The HE3DA® battery technology is based on nanomaterials, special inorganic separators and several millimeters thick electrodes. It is ideal for production of high capacity batteries and large energy storage modules.

This fully inorganic battery does not contain any organic melting parts, demonstrates a very low internal resistance, allows easy degassing and shows a number of other advantages that are not possible to utilize by the conventional 2D technologies. This 3D battery technology provides an inherited safety to the batteries, enabling construction of very large cells on MWh level and modules on hundreds of MWh scale. HE3DA® system significantly simplifies the BMS.
In Operando Li+- Activity Measurements in Lithium Ion Batteries - a Method to Develop and Optimize Safe Operating Strategies Even at Unfavourable Conditions
Authors: Hogg Bjoern-Ingo , Wohlfahrt-Mehrens Margret
Published: February 2020

The deposition of lithium on the surface of graphitic anodes in Lithium-ion batteries is a major concern about safety and lifetime of lithium-ion batteries.

The deposition can be caused by high anodic overpotentials at low temperatures or exceeding a critical lithium ion concentration at the graphite particle surface. The prediction of the onset of lithium deposition by modelling is rather difficult because there are no reported values for the Li+ activity in the electrolyte or their changes during lithium ion insertion into graphite. Furthermore the modelling of the Li+ activity in the electrolyte is quite challenging because the needed parameters like the diffusion coefficient of Li+inside the particles depend strongly on the state of charge and the absolute value on the measuring method respectively the texture of the electrode coating [1].

The critical Li+ activity in the electrolyte in matters of a lithium deposition follows from the concentration dependency of the Li/Li+potential, which is described by the Nernst equation.

In the present study, we take advantage of the concentration dependency and develop a 4-electrode cell design (Figure 1a), which allows to measure potential changes of the metallic lithium reference electrode of the standard three electrode setup.

The potential shifts of the metallic lithium reference correlate directly with changes in the Li+ activity in the electrolyte. We studied the interaction of lithium transport and reaction kinetics in dependency of current density, temperature and active material of the anode and the cathode. The measurements indicate a direct correlation between changes in anodic and cathodic reaction kinetics and the Li+concentration in the electrolyte (Figure 1b).

Based on the knowledge of the Li+activity and its variation, we were able to improve an operation strategy for Lithium-Ion batteries and match the cell components with each other in terms of avoiding lithium deposition.

References

[1]B: Markovsky, M.D. Levi and D. Aurbach, Electrochimica Acta ,
43, 2287(1998)

Figure 1
Failure Mechanism Investigation of Commercial LiFePO4 Cells in Different Operating Conditions
Authors: Liu Yadong , Liu Qi , Li Zhe-Fei , Yang Fan , Ren Yang , Lu Wenquan , Xie Jian
Published: February 2020

The rapid growth of the Li-ion battery (LIB) market has greatly driven research on LIBs, particularly on LIB failure mechanisms under different operating conditions (long-term cycling, overcharge, over-discharge, high temperatures, low temperatures, etc.) due to safety issues1. Up to now, there are only very few of reports on the capacity fade mechanisms in the commercial batteries2. It is paramount of scientific and engineering importance to understand the microstructure evolution during normal cycle in the commercial cells. To our knowledge, in situ monitoring of microstructure evolution during the capacity fade process in either a commercial battery or lab-made batteries has never been reported before.

In this work, the capacity fade/failure processes of commercial 18650 LiFePO4 cell during the long term normal charge/discharge, overcharge, and over-discharge cycling was systematically investigated respectively. The commercial 18650 LiFePO4cells (A123 Systems) were chosen to be cycled for all cycling conditions until these cells reach 80% of initial capacity (typical criteria for EV application) or cannot be charged/discharged.

The cells were in situ characterized and the microstructure of the electrodes was investigated using synchrotron high-energy X-ray diffraction during long term normal cycling and overcharge/over-discharge cycling conditions. Synchrotron high-energy X-rays with photon energy of 115 KeV are capable of penetrate through thick samples, which allows us to probe commercial 18650 LiFePO4 cells without any cell modification and the results are presented herein. The result of 18650 cell after 2500 cycles is shown in Fig. 1. Our in situ experiment result show that loss of the active lithium source in the system is the primary cause of the capacity fade and the appearance of the inactive FePO4phase is proportional to the decrease of available lithium source during cycling.

Electrochemical Impedance Spectroscopy (EIS) is a powerful and quick analytical and diagnostic tool that can be used to study the internal resistance of Li-ion batteries during long-term normal cycling or overcharge/ over-discharge cycling3. The EIS results during overcharge and over-discharge process are shown in Fig.  2 and 3 respectively, and the de-convoluted Ohmic resistance, solid electrolyte interphase (SEI) resistance, and Warburg Coefficient, change with cycle number in some patterns, indicating the occurrence of corrosion of the current collector, SEI breakdown/decomposition and reformation, and the development of diffusion barriers of Li+ in the electrode, respectively. These parameters are associated with failure and can be used as indicators of incoming failure. Overall, EIS can be used as an effective and reliable tool to monitor the state of health, predict incoming failure of the LIB cells, and issue a warning before failure without disturbing the operation of the cells.

Figure 1
(Invited) Impact of Nafion Dispersion Morphology on Fuel Cell Performance and Durability
Authors: Kim Yu Seung , Welch Cynthia , Hjelm Rex , Mack Nathan , Johnston Christina , Choi Baeck , Langlois David A. , Lee Kwan-Soo , Orler Edward Bruce , Labouriau Andrea , More Karren , Xu Hui , Willey Jason , Mittelsteadt Cortney K
Published: February 2020

Los Alamos National Laboratory fuel cell team has discovered that Nafion dispersion morphology in dilute liquid media ca. solid content: 2.5 wt.% has distinctive characteristics, depending on dispersing fluid:[ref. 1] Small angle neutron scattering (SANS) and 19F NMR analysis indicated (i) a well-defined cylindrical dispersion in polyhydric alcohols, (ii) a gel particles that have as open network structure with sufficiently sparse physical network connections in some aprotic dispersing fluids, and (iii) a less-defined highly solvated large particle in water-monohydric alcohol mixtures.

In this talk, we present the impact of dilute Nafion dispersion morphology on film/electrode formation, fuel cell performance and durability. Following subjects will be discussed with some details:

1. Change of particle morphology and gelation behavior of Nafion dispersion during evaporation process (Fig.1).[ref. 2]

2. Characterization of fuel cell electrode by microscopy and electrochemical methods.

3. Impact on fuel cell initial and long-term performance during potential cycles.[ref. 3]

Other critical effects including mechanical toughness of dispersion-cast membranes and electrode reaction uniformity [ref. 4] will be also discussed at the meeting. This presentation will give some insights on recent progress of engineering production and processing of perfluorinated sulfonic acid ionomers and their application for fuel cell membrane and electrode processing.

Acknowledgment U.S. Department of Energy Fuel Cell Technologies Program (Dr. Dimitrios Papageorgopoulos)

References 1. Welch, C.; Labouriau, A.; Hjelm, R.; Orler, B.; Johnston, C.; Kim, Y. S. ACS Macro Letters, 2012, 1, 1403-1407. 2. Kim, Y. S. Welch, C. F. Hjelm, R. P. Mack, N. H. Labouriau, A. Orler, E. B. Macromolecules 2015, 48, 2161-2172. 3. Kim, Y. S. Welch, C. F. Mack, N. H. Hjelm, R. Orler, E. B. Hawley, M. Lee, K. S. Yim, S.-D. and Johnston, C. M. Phy. Chem. Chem. Phy. 2014, 16, (13) 5927-5932. 4. Choi, B., Langlois, D. A. Mack, N. Johnston, C. M. Kim, Y. S. J. Electrochem. Soc. 2014, 161 (12), F1154-F1162.

Figure 1
DFT-Based Screening for a New Electro-Catalyst to Convert Nitrigen to Ammonia at Room Temperature and Ambient Pressure
Authors: Abghoui Younes , Skulason Egill
Published: February 2020

Computational screening for new catalysts that are stable, active and selective towards electrochemical reduction of nitrogen to ammonia at room temperature and ambient pressure is presented from a range of transition metal nitride surfaces. Density functional theory (DFT) calculations are used to study the thermochemistry of cathode reaction so as to construct the free energy profile and to predict the required onset potential via the Mars-van Krevelen mechanism. Stability of the surface vacancy, stability of the catalyst against decomposition as well as poisoning possibility under operating conditions are investigated towards catalyst engineering for distributable and sustainable ammonia formation. The most promising candidates turned out to be the (100) facets of rocksalt structure of VN, CrN, NbN and ZrN that should be able to form ammonia at -0.51 V, -0.76 V, -0.65 V and -0.76 V vs. SHE, respectively. Another interesting result of the current work is that for the introduced nitride candidates, hydrogen evolution is no longer the competing reaction; thus, high formation yield of ammonia is expected at low onset potentials.

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

Typically, energy consuming systems are run off the traditional grid. However, there are remote areas of the United States that don’t have access to the traditional grid and in those places, there is a need for photovoltaic generation to supply those electricity needs [1].The use of photovoltaics along with lithium batteries for storing excess energy has increased due to the need for renewable energy as a viable source of electricity. Such energy storage systems (ESS) are useful for complex irrigation systems that assist in the cultivating of the United States food supply [2].  Without the ESS systems, maintaining a stable economy may be difficult in extreme cases.

  The object of this research will be to construct a virtual photovoltaic generation system that is capable of powering an irrigation system, and it will also be used in tandem with a lithium-ion battery storage system.  The focus of this irrigation system will be to water a tomato farm in the Florida climate. The work will be performed in a virtual environment using a modular approach to a system-level design that simulates the behavior of the photovoltaic system and the degradation of the lithium-ion battery pack.  Ultimately, these results suggest the necessary components for a real photovoltaic and battery operated system require the optimally sized photovoltaic panel and inverter connected to a watering pump. The PV panels convert solar energy to electrical energy with DC current and the inverter converts DC current to AC current required to run the pump. In addition, Additional information from hygrometer readings and weather profile also would be needed with a optimizing algorithm to ensure efficient irrigation operation.

Acknowledgment

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

References

 

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

 

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

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

Bulk-type all-solid-state lithium-ion batteries with nonflammable inorganic solid electrolyte are being considered as the ultimate solution for safe lithium-ion batteries. The current all-solid-state lithium-ion batteries suffer from low power density mainly due to strong kinetic limitation at the electrode/electrolyte interface. Here, we report a novel concept of a single-material all-solid-state lithium-ion battery, wherein a single Li10GeP2S12 serves as an electrolyte, an anode, and a cathode, to eliminate the highly resistive interface between the electrodes and electrolyte. The realization of the single-Li10GeP2S12 battery is based on the fact that the Li-S and Ge-S components in Li10GeP2S12 could act as the active centers for lithiation/delithiation as a cathode and an anode, respectively, when electronically-conductive carbon is mixed, while pure Li10GeP2S12 can be used as an electrolyte. This unique concept of a single-material lithium-ion battery can be extended to other solid-state battery systems, providing a new direction for high-power, high-energy, long-cycling solid-state batteries.

This work was mainly supported as part of Nanostructures for Electrical Energy Storage (NEES), an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Award Number DESC0001160.
Mixed Metal Phosphorous Oxides: Prospects for Secondary Lithium Based Batteries
Authors: Marschilok Amy C , Takeuchi Kenneth J , Takeuchi Esther S
Published: February 2020

Cathode materials containing phosphate have met with success in lithium based batteries, with a notable example being lithium iron phosphate, LiFePO4.  A recent focus for our research has been the investigation of bimetallic phosphates (MM’PxOy, where Mn+ = Ag, Cu), motivated by the desire to obtain the stability observed in phosphate based cathode materials and the opportunity for multiple electron transfers per formula unit due to the bimetallic composition of the materials.

Our initial electrochemical studies focused on Ag2VO2PO4 where the material provided a discharge capacity of 272 mAh/g and high current pulse capability.  In-situ formation of silver nanoparticles upon initiation of reduction was accompanied by a 15,000 fold increase in cathode conductivity.  Our paradigm of current enhancement via reduction displacement was in evidence.

An alternate composition Ag0.48VOPO4 material with lower silver content per formula unit shows a high operating voltage and characteristic multi-plateau voltage profile.  Counter to Ag2VO2PO4, the reduction of Ag+ to Ag0 occurs later in the discharge process for Ag0.48VOPO4.

Based on the delayed reduction of silver, we hypothesized that the MVOPO4 material class may demonstrate improved reversibility relative to the AgVO2PO4 system.  The MVOPO4 material is explored for secondary lithium based battery applications.  The electrochemistry of the analogous silver and copper containing MVOPO4 materials will be compared and contrasted in this presentation.  The inclusion of copper instead of silver in the structure is motivated by lower cost of copper versus silver and the accessibility of divalent Cu2+ which can provide 2 electron equivalents per metal center.  However, the silver containing material offers the advantage of higher operating voltage.  The electrochemistry will be summarized in the context of prior work other members of the MM’PxOy and MM’O material families.
The Thermal and Structural Behavior of Li-Rich Cathode Materials Investigated By Synchrotron-Based X-Ray Techniques
Authors: Muhammad Shoaib , Kim Hyunchul , Jang Donghyuk , Kim Yunok , Yoon Jaesang , Jeong Mihee , Lew Gil Hwan , Yoon Jaegu , Park Jin-Hwan , Yoon Won-Sub
Published: February 2020

Recently, composite layered material between Li2MnO3 and LMO2 (where M= Mn, Co, Ni), also known as the lithium rich cathode material, has received pronounced attention and has been considered as promising cathode materials due to their high discharge capacity of ~250 mAh g-1 . However, there are several intrinsic problems associated with this material family that need to be solved; e.g., the voltage as well as the capacity decay during cycling, the high irreversible capacity loss in the first cycle, poor rate capability, and oxygen release during cycling, in order to adopt these materials in practical cells. Thermal stability is another challenge which could greatly impact the safety of lithium-ion batteries. In this study, we use in situ X-ray diffraction technique to elucidate the thermal degradation mechanism of 0.5Li2MnO3-0.5LiNi0.33Co0.33Mn0.33O2 lithium rich cathode material in the absence and presence of electrolyte to simulate the real life battery conditions and compare its thermal behavior with the commercial LiNi0.33Co0.33Mn0.33O2 cathode material. We show that the thermal induced phase transformations in delithiated lithium rich cathode material are much more intense compared to similar single phase layered cathode material in the presence of electrolyte.
Study of 2R-Cell Equipped with LSC and LSCF Cathodes under Thermic and Redox Cycling
Authors: Coquoz Pierre , Grize Carolina , Ruiz Jesus , Bourradou Anais , Diethelm Stefan , Singh Vaibhav , Ihringer Raphaël
Published: February 2020

The 2R-Cell, developed by Fiaxell Sàrl, provides robustness and reliability upon multiple thermic and redox cycles. In this article we present the results of 2R-Cell tested under thermic and redox cycles. Different cathodes were studied, composite LSC-GDC and LSCF, in terms of electrical performances and resistance to thermic cycles. Degradation due to multiple thermic and redox cycles is reported and discussed. Three composite LSC-GDC cathodes were tested (40, 60 and 75 % GDC). Surprisingly the highest power density was achieved with a cathode containing 75% of GDC in the composite layer. The cell provided a current density of 1060 [mA/cm2] at 0.8 V and 780°C, before thermic cycling. This cell underwent 40 thermic cycles with an average power loss of 0.7 % per cycle and providing a power of 621 [mW/cm2] at the end. A LSCF cathode equipped 2R-Cell, tested by EPFL our partner in an EU project (Roxsolidcell), was subjected to 20 thermic cycles and 20 redox cycles. With this cathode material the average ASR increase was 0.3% per thermic cycle and 0.5 % per redox cycle. SEM pictures of the tested cells after thermic and redox cycles are presented and discussed.
Residual Stress in NiO-YSZ Composites and Its Relationship to Microstructure
Authors: Akaza Yoshiki , Syu Takaho , Iguchi Fumitada , Shimizu Makoto , Yugami Hiroo
Published: February 2020

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

 

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

 

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

 

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

 

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

Ni/YSZ composite materials have shown the tremendous success over past years for application as SOFC anodes. One of the biggest advantages of Ni/YSZ SOFC anode is its ability of direct utilization of various fuel types, i.e. H2/H2O, CO/CO2 and hydrocarbons. It is, however, well known that operation of those anodes upon various fuels could cause various types of cell degradation. Therefore, the replacement of Ni cermet with alternative ceramic materials is essential to develop long-term operating SOFC technology.

In the present contribution, we combine modeling and experimental study of electrochemical hydrogen oxidation at an alternative perovskite based mixed-conducting SOFC anode with and without an addition of nickel. Composite electrodes were produced by conventional wet ceramic processing (screen printing – spraying) and sintering on YSZ electrolytes (La0.1Sr0.9TiO3-α-Ce1-xGdxO2-α | YSZ) with different compositions and microstructure, and were electrochemically characterized using symmetrical button-cells configuration. An elementary kinetic model was developed and applied to explore the performance of LST based SOFC anode. A detailed multi-step heterogeneous chemical and electrochemical reaction mechanism was established taking into account transport of ions in all ionic phases, and gas transport in channel and porous media. It was found that heterogeneous chemistry at LST surface has capacitive behavior that alters the impedance spectra. In addition, surface charge-transfer reaction, which describes partial oxygen ionization, caused impedance feature and is rate-limiting at high temperature. However, if nickel is added to composite perovskite anodes the impact of LST surface chemistry is diminished leading to an improvement of cell performance.
Kinetic Monte Carlo Simulations of Solid Oxide Fuel Cell Cathode
Authors: LI Meiling , NI Meng
Published: February 2020

The cathode microstructure is critical to development of high performance solid oxide fuel cells (SOFC).  In this work, a 3D kinetic Monte Carlo (kMC) model is developed to study the microstructure evolution of SOFC composite cathodes during the sintering process.  Conventional Lanthanum Strontium Manganite (LSM)-Yttria-stabilized Zirconia (YSZ) composites are used as model in the parametric simulations.  The important sintering mechanisms are considered, including surface diffusion, grain boundary migration, vacancy creation, and annihilation.  The triple-phase boundary (TPB) and effective conductivities of LSM and YSZ are computed during the sintering procedure.  The effects of sintering temperature, initial particle size, and material composition on the cathode microstructure are studied and discussed.  Optimal sintering conditions are recommended for high performance cathode design.
Sulfur Tolerance of Au-Mo-Ni/GDC SOFC Anodes Under Various CH4 Internal Steam Reforming Conditions
Authors: Neofytides Charalampos , Athanasiou Michalis , Neophytides Stylianos G. , Niakolas Dimitrios K.
Published: February 2020

The present work refers to the short communication of a first series of obtained results on how Au and/or Mo addition can affect the stability of modified Ni/GDC anodes for the reaction of internal CH4 steam reforming, in the presence of H2S. Specifically, it is shown that Ni/GDC is stable in the presence of 10 ppm H2S, but only in the case where 100 vol% of H2 is the anode feed. In the case where CH4 and H2O (diluted in Helium carrier gas) comprise the anode feed, then at ratios equal to S/C = 2 or S/C = 0.13 the performance of Ni/GDC shows severe degradation, while the Au-Mo-Ni/GDC anode has the best and most stable electrocatalytic behavior. Finally, the effect of the electrocatalyst`s loading on the sulfur tolerance is also investigated.
Oxygen Nonstoichiometry and Cathodic Property of Ce0.6Mn0.3Fe0.1O2-δ for High Temperature Steam Electrolysis Cell Using LaGaO3-Based Oxide Electrolyte
Authors: Hosoi Kohei , Sakai Takaaki , Ida Shintaro , Ishihara Tatsumi
Published: February 2020

The reverse operation of SOFCs, so called solid oxide electrolysis cells (SOECs), can efficiently produce hydrogen from high temperature steam. Ni-based metal, which are widely used for anode of the conventional SOFCs, are also widely used for the cathode of SOECs due to its high catalytic activity and high electronic conductivity. However,  Ni-based cathodes frequently showed low stability against oxidation resulting in deactivation under SOECs condition. As a result, Ni-based electrodes are easily aggregated and also delaminated from electrolyte. Therefore, it is essentially required to recycle a part of produced hydrogen to the Ni based electrodes for preventing the oxidation of Ni, however, this recycle of the part of hydrogen formed requires the complicated system and also decrease the electrolysis efficiency. In order to solve these problems, recently, oxide cathode have been attracting much attention for the cathod of SOECs instead of Ni-based metal. Since oxide cathode is stable in redox cycles, recycles of hydrogen is not required. However, oxide cathode have some disadvantages, for instance, low catalytic activity and also low electronic conductivity. In this study,  Mn- and Fe-doped CeO2 (Ce0.6Mn0.3Fe0.1O2, CMF) was investigated as a new oxide cathode for SOECs. CMF is a mixed ionic and electronic conductor (MIEC), and has been reported as a potential anode catalyst for SOFCs. Although its electrical conductivity is lower than that of the typical perovskites oxide electrode materials (10-1 S/cm at 900 °C), its catalytic activity for electrode reaction was enough high when it is used in SOFCs. 

Oxygen nonstoichiometry in this CMF was studied by thermogravimetry.  It was found that higher oxidation state of Mn and Fe was observed resulting in hole conduction.  The origin of this hole conduction was further studied by XPS measurement.  On the other hand, in reducing atmosphere, because of the reduction of Ce, n-type semiconduction is observed. Therefore, oxygen nonstoichiometry of CMF is discussed in details from valence number of Ce, Mn, and Fe.

On the other hand, CMF cathode showed almost the same performance with that of  Ni-SDC cathode in steam electrolysis and  hydrogen evolution rate well obeys the Faraday’s law in temperature range of 900-700°C and stable electrolysis performance was observed. The XRD pattern and the SEM images of CMF cathode after the electrolysis measurement revealed that the CMF phase is stably remained and aggregation or delamination were hardly observed. These results suggest that CMF is highly promising as oxide cathode for SOECs
Influence of Substrate on Conductivity of Sr and Mg Doped Lanthanum Gallate Thin Film Electrolyte for Solid Oxide Fuel Cell
Authors: Dempoh Akishi , Endo Yoichi , Terai Takayuki , Suzuki Akihiro
Published: February 2020

Solid oxide fuel cell (SOFC) consisting of ion conductive ceramics has various advantages such as the high generating efficiency, the utilization of hydrocarbon-containing fuel and the non-necessity of expensive rare metal catalyst. Yttria-stabilized Zirconia (YSZ) or Gadolinium-doped Ceria (GDC) are mainly used as the electrolyte for SOFC. Strontium- and Magnesium-doped Lanthanum Gallate (La0.9Sr0.1Ga0.8Mg0.2O3-δ, LSGM) has higher conductivity than YSZ, negligible electronic conduction and high chemical stability in a wide oxygen partial pressure range compared to GDC.

Recently, it was reported that YSZ and GDC thin films have different values of ion conductivity from those of the bulk. LSGM should have the similar phenomenon. The reason for this change of the conductivity is assumed to be the lattice strain in the thin film, the difference between the bulk resistivity and the grain boundary resistivity or space charge layers at homo- or hetero-junctions. However, the mechanism of the conductivity change of LSGM thin film from the bulk is not revealed.

In this study, the radio frequency magnetron sputtering, which is a reliable method for preparing thin film, was used for obtaining various thickness films on sapphire and quartz substrate. However, the deposited film was amorphous. To obtain the crystallized LSGM film, we investigated the influence of the annealing temperature. By proper post-annealing, crystallized LSGM film was obtained. We evaluated the crystallinity by X-ray diffraction, observed the microstructure with a scanning electron microscope and measured the conductivity by electrochemical impedance spectroscopy. In this paper, we report the effect on the electrical conductivity of the difference of thermal expansion co efficiency between LSGM thin film and the substrate.
Performance Degradation Prediction of a Low-Temperature SOFC via Impedance Spectroscopy and CFD Modelling
Authors: Boigues Muñoz Carlos , Pumiglia Davide , Santoni F , McPhail Stephen J. , Comodi Gabriele , Carlini Maurizio
Published: February 2020

The on-going EU-funded project New all-European high-performance stack: design for mass production (NELLHI) foresees the manufacturing and validation of SOFC stacks produced by Elcogen, seeking a substantial increase in electrical performance and cost reduction of individual stack components. The present work encompasses the immediate performance characterisation of a first generation LSC-based SOFC single cell by means of polarization curves, electrochemical impedance spectroscopy (EIS), the distribution relaxation times (DRT) method and equivalent circuit modelling (ECM). Besides, an endurance performance characterisation based on the FCTESQA testing protocols along with EIS measurements, the aforementioned ECM and computational fluid dynamics (CFD) modelling theory has enabled to generate a time-dependent model capable of predicting performance degradation of the single cell when operating under predetermined conditions.
Performance Degradation Analysis of Different Type SOFCs
Authors: Yoshikawa Masahiro , Yamamoto Tohru , Asano Koichi , Yasumoto Kenji , Mugikura Yoshihiro
Published: February 2020

Solid oxide fuel cells (SOFC) technology has been developed by many manufacturers and there are various types of stacks having different design and materials. CRIEPI started to make detailed analyses on cell/stack performance by changing gaseous compositions in anode and cathode to establish the representation scheme for six different types of SOFCs, which have been developed by MHPS, Kyocera, TOTO, NTK, NGK, and Murata under the new NEDO project from FY2013 to FY2017. In this study, we report our recent activities toward the durability improvement of SOFCs based on the electrode performance model.