bluuebunny/crossref_metadata_2025 huggingface dataset:
Covalent Immobilization of Thiolated Oligonucleotide Onto Glassy Carbon: A Cost-Effective Alternative for Genosensor Fabrication
Authors: O Sullivan Ciara
Published: February 2020

Abstract not Available.
Investigation of Oxygen Reactions in a Screenprinted Pt/YSZ-Model Electrode System
Authors: Zheng Yingjing , Sauter Ulrich , Kunz Lothar , Streeb Martin , Oehler Gudrun , Sahner Kathy , Moos Ralf
Published: February 2020

Abstract not Available.
"UV Or Blue LEDs With Phosphors: An Interesting Way to Develop Smart Lighting.”
Authors: Chadeyron Geneviève
Published: February 2020

Abstract not Available.
Publishing Luminescence and Display Materials Content in ECS Journals: Past, Present, and Future
Authors: Hess Dennis W.
Published: February 2020

Abstract not Available.
Systematic Crystal Field Studies of Mn4+-Doped Perovskites
Authors: Srivastava Alok , Brik Mikhail G.
Published: February 2020

Abstract not Available.
Interesting Theoretical Problems in Luminescence From Solids
Authors: Mishra Kailash C. , Johnson Keith H. , Piquette Alan
Published: February 2020

Abstract not Available.
Combined Crystal Field and First Principles Studies of the Y2O2s Phosphor Doped With Yb3+ and Er3+
Authors: Gangadharan Ajith Kumar , Pokhrel Madhab , Brik Mikhail G. , Sardar Dhiraj Kumar , Ma Chong Geng
Published: February 2020

Abstract not Available.
Enhanced Luminescent Properties of Europium Complex By Replacement of Water Molecules By 2, 2'-Bipyridine
Authors: Lather Rajesh Kumar
Published: February 2020

Abstract not Available.
Luminescent Characteristics of Polyethylene Terephthalate (PET) Thin Films Deposited By Spray Pyrolysis Using Rare Earths (RE3+) As Dopants
Authors: Carmona-Tellez Salvador , Aguilar-Frutis Miguel Angel , Alarcón-Flores Gilberto , García-Hipolito Manuel , Zaleta-Alejandre Efraín , Meza.Rocha Abraham , Rivera-Álvarez Zacarias , Martínez-Martínez Rafael , Falcony Ciro
Published: February 2020

Abstract not Available.
Critical Overviews About Conventional Ideas for White-LED (Oxy)Nitride Phosphors: Covalency and Stiffness
Authors: Mikami Masayoshi
Published: February 2020

Abstract not Available.
Effect of Flux On Luminescence of Eu2+ Activated Yellow Oxynitride Phosphor
Authors: Nammalwar Prasanth Kumar , Manepalli Satya Kishore , Porob Digamber G , Setlur Anant A
Published: February 2020

Abstract not Available.
Novel Synthesis Methods for Luminescent Materials: Spark Plasma Sintering (SPS) and Micro Arc Oxidation (MAO)
Authors: Hong Seong-Hyeon , Kang Eun-Hee
Published: February 2020

Abstract not Available.
In-Situ Synchrotron X-Ray Diffraction Study of the Heat Treated Electrolytic Manganese Dioxide Cathode Used in Primary Li/MnO2 Batteries
Authors: Donne Scott W , Dose Wesley M
Published: February 2020

Abstract not Available.
Bismuth Ferrites As Electrodes for Lithium Batteries: An in Situ XRD and XANES Investigation
Authors: Wen Wen , Liu Min , Yang Tieying , Yin Guangzhi , Gu Yueliang , Gao Xingyu , Zhou Xingtai , Gong Zhengliang , Lin Chuan
Published: February 2020

Abstract not Available.
Efficient Reformulation of Pressure Induced Solid Phase Diffusion in Coupled Electrochemical-Mechanical Models for Lithium Ion Batteries
Authors: De Sumitava , Suthar Bharat Kumar , Subramanian Venkat R
Published: February 2020

Abstract not Available.
Unraveling the Oxygen Reduction Reaction Mechanism and Activity of Composite Ba0.5Sr0.5Co0.8Fe0.2O3-
d/Carbon Electrodes in Alkaline Media By Thin Film Rotating Ring Disk Electrode Measurements
Authors: Fabbri Emiliana , Mohamed Rhiyaad , Levecque Pieter , Conrad Olaf , Koetz Ruediger , Schmidt Thomas J.
Published: February 2020

Abstract not Available.
Mn Based NPM Catalyst for Oxygen Reduction Reaction in Acidic Medium for Pemfcs
Authors: Ramanujam Kothandaraman , M P Karthikayini
Published: February 2020

Abstract not Available.
Effect of Samaria-Doped Ceria Cathodic Interlayer On LT-SOFC Kinetics
Authors: Kim Young-Beom , An Jihwan , Gür Turgut M. , Prinz Fritz B.
Published: February 2020

Abstract not Available.
MnO2-Carbon Nanotube Electrodes for Electrochemical Supercapacitor
Authors: Chun Young-Gab
Published: February 2020

Abstract not Available.
Zinc Oxide Nanorod Arrays Based Dye-Sensitized Solar Cells and Its Photovoltaic Performance in Indoline Dye System
Authors: Kim Hyungjin , Mali Sawanta S. , Hong Chang Kook
Published: February 2020

Abstract not Available.
Keynote--Recent Biomedical Applications of Dielectrophoresis
Authors: Pethig Ronald
Published: February 2020

Abstract not Available.
Distinguished Invited Speaker--3D Printing of Intricate Soft and Wet Systems
Authors: Furukawa Hidemitsu
Published: February 2020

Abstract not Available.
Separation and Preconcentration Of Viable Pathogens By Chemotaxis
Authors: Xu Jie , Hesketh Peter J.
Published: February 2020

Abstract not Available.
Microcantilever Sensors Loaded With Sensing Nanomaterial for On-Site Detection and Monitoring of Trace-Level Bio/Chemical Molecules
Authors: Li Xinxin
Published: February 2020

Abstract not Available.
Strategies for Isolation of Phage Displayed Oligopeptide Probes for Rapid Detection of Pathogenic Salmonellae
Authors: Tong Zhou , Silo-Suh Laura A , Suh Sang-Jin
Published: February 2020

Abstract not Available.
Gene Direct Identification By Site-Specific Enzyme Cutting Double-Strand DNA On a Resonant-Cantilever
Authors: Li Xinxin , Xu Tiegang , Zheng Dan
Published: February 2020

Abstract not Available.
A Fresh Look On Liquid-Electrolyte-Li/S-Batteries: Non- Equilibrium Thermodynamics Based Modeling of Transport and Reactions
Authors: Hofmann Andreas Felix , Latz Arnulf
Published: February 2020

Abstract not Available.
Characterization of Layered Transition Metal Oxide Na-Ion Battery Cathode in a Neutral Aqueous Electrolyte
Authors: Frankforter Kevin Jerome , Anderson Marc Arlen
Published: February 2020

Abstract not Available.
Electrochemical Properties and Thermal Characteristics of Feof Cathode for Na-Ion Batteries
Authors: Zhao Liwei , Kitajou Ayuko , Okada Shigeto
Published: February 2020

Abstract not Available.
Carbon-Free Cobalt Oxide Cathodes With Tunable Nanoarchitectures for Rechargeable Lithium-Oxygen Batteries
Authors: Lee Jong-Won , Jung Kyu-Nam , Riaz Ahmer , Lee Seung-Bok , Lim Tak-Hyoung , Park Seok-Joo , Song Rak-Hyun , Shin Kyung-Hee
Published: February 2020

Abstract not Available.
Combined DFT and Dems Study On the Role of CO2 Poisoning On the Electronic Conduction and Overpotentials in Li-Air Batteries
Authors: Vegge Tejs , Garcia-Lastra Juan Maria , Højberg Jonathan , Younesi Reza , Mekonnen Yedilfana Setarge , Myrdal Jon S. G. , Knudsen Kristian B. , Norby Poul
Published: February 2020

Abstract not Available.
The Reaction of Sb-Based (inter)Metallics As Na-Ion Negative Electrode Materials
Authors: Veith Gabriel M , Zawodzinski Thomas A. , Sun Che-Nan , Baggetto Loic , Ganesh P. , Gorka Joanna
Published: February 2020

Abstract not Available.
Stable Interfaces of Solid Electrolytes With LiFePO4 Cathode During Charge and Discharge Operations
Authors: Kurita Tomochika , Watanabe Satoru , Yamamoto Tamotsu , Tanaka Tsutomu
Published: February 2020

Abstract not Available.
Electrochemical Modeling of Insertion/Extraction Reactions of Mg in Mg/Bi Electrode
Authors: Ramanathan Mayandi , Benmayza Aadil , Prakash Jai , Singh Nikhilendra , Arthur Timothy S. , Mizuno Fuminori
Published: February 2020

Abstract not Available.
Investigation of Performance and Stability of Li-O2 Batteries in Terms of Electrolyte and Catalyst Material
Authors: Kalubarme Ramchandra S. , Park Chan-Jin
Published: February 2020

Abstract not Available.
An Alternative Configuration for Room Temperature Sodium Ion-Sulfur Battery
Authors: Lee Dong-Ju , Park Ju-Won , Hasa Ivana , Sun Y.-K. , Scrosati Bruno , Hassoun Jusef
Published: February 2020

Abstract not Available.
Redox Active Molecular Engineer for Energy Storage
Authors: Zhang Lu , Vaughey John T , Burrell Anthony K.
Published: February 2020

Abstract not Available.
(De)Lithiation Mechanism of Se-Based Lithium Batteries Determined By In-Situ Synchrotron X-Ray Probes
Authors: Cui Yanjie , Abouimrane Ali , Lu Jun , Bolin Trudy , Ren Yang , Weng Wei , Sun Chengjun , Maroni Victor A. , Heald Steve M. , Amine Khalil
Published: February 2020

Abstract not Available.
Electrochemical Splitting of Lif: A New Approach to Lithium-Ion Battery Materials
Authors: Dimov Nikolay , Kitajou Ayuko , Hori Hironobu , Kobayashi Eiji , Okada Shigeto
Published: February 2020

Abstract not Available.
SECM Study of Optimization of the Electrochemical Reaction Mechanism At the Air Cathode for Zinc-Air Secondary Element
Authors: Gui Alicia Lei , Wittstock Gunther
Published: February 2020

Abstract not Available.
Perspectives On Factors Controlling Thermal Runaway of Li-Ion Batteries
Authors: Sriramulu Suresh , Stringfellow Richard , McCoy Christopher , Rempel Jane , Hyung YooEup , Barnett Brian
Published: February 2020

Abstract not Available.
In Situ Measurement of Li-Ion Battery Internal Temperature
Authors: Zhang Guangsheng , Cao Lei , Ge Shanhai , Wang Chao-Yang , Shaffer Christian E , Rahn Christopher D
Published: February 2020

Abstract not Available.
Effects of Electrode Density On the Safety of NCA Positive Electrode for High Capacity Li-Ion Batteries
Authors: Kim Gu-Yeon , Dahn Jeff
Published: February 2020

Abstract not Available.
Preparation of Extremely Small Pt Nanoparticle Catalysts and Their Electrocatalytic Activity for Oxygen Reduction Reaction
Authors: Inoue Hiroshi , Yamazaki Toshiki , Chiku Masanobu , Higuchi Eiji
Published: February 2020

Introduction

Polymer electrolyte fuel cells (PEFCs) have attracted great attention as the next generation energy device for electric vehicles due to their high energy conversion efficiency and low emission of pollutants. Pt nanoparticles-loaded carbon black (Pt/CB) is widely used as an electrocatalyst in PEFCs. However, it is necessary to minimize the consumption of Pt because of its high cost and diminishing reserves.

CO is known to be strongly adsorbed on Pt atoms. If Pt nanoparticles are prepared in a CO atmosphere, the growth of Pt may be suppressed. Based on the above idea, we have prepared a Pt-carbonyl cluster complex ([Pt3(CO)3 (μ-CO)3]3
2−) by bubbling CO in an acetonitrile-water (1:1 in volume ratio) mixed solution containing PtCl6
2−.1 The complex spontaneously adsorbed on CB, and oxidatively broke and aggregated to form Pt nanoparticles in air. The resultant Pt nanoparticles had the monodispersed particle size of 1.8±0.3 nm. If the Pt-carbonyl cluster complex were fixed on CB with a stabilizer, the aggregation of the resultant Pt nanoparticles could be suppressed. In this study, we designed to inhibit the growth of Pt nanoparticles by electrostatically binding several kinds of stabilizers with the anionic complex on CB before converting to Pt. We characterized the resultant extremely small Pt nanoparticles-loaded CB and evaluated its catalysis for oxygen reduction reaction.

Experimental

Several cationic molecules, polydiallyldimethylammonium-chloride (PDDA), methyl-viologen(MV), benzyl-viologen(BV), cetyltrimethylammonium-bromide(CTA), pyridine(Pyr), bipyridine(Bpy) and terpyridine (Tpy), were used as a stabilizer in this study. They were mixed after the Pt-carbonyl cluster complex dianion was adsorbed on CB, leading to the production of ionic couples due to electrostatic interaction.

Results and Discussion

Pt nanoparticles prepared with stabilizers except CTA were smaller in mean size than conventional Pt nanoparticles (ca. 1.8 nm) prepared without stabilizer, suggesting that each stabilizer inhibited the growth of Pt nanoparticles on CB.

In ORR, specific activity (SA), activity per unit electrochemical surface area of Pt, and mass activity (MA), activity per mass of Pt, for the Pt/CB catalyst prepared with bipyridine (Pt/CB+Bpy) were ca. 1.4 and 1.6 times higher than those of the commercial catalyst (Pt/CB-TKK(Tanaka Kikinzoku Kogyo TEC10E50E)), respectively. X-ray photoelectron spectra exhibited that in Pt(4f) core level spectra of Pt/CB+Bpy, a peak assigned to metallic Pt shifted to higher binding energy because of the final state effect and a decrease in electron density of Pt surface atoms due to adsorption of electron-withdrawing stabilizers, which seems to weaken Pt-O bond and increase SA and MA.

Reference

1. E. Higuchi, A. Taguchi, K. Hayashi, H. Inoue, J. Electroanal. Chem., 663, 83-89 (2011).
From Lab Scale to Large Volume Production: Substitution of Toxic NMP/PVDF with H2o/CMC/SBR in Lithium-Ion Cells
Authors: Noll Pascal , Hörpel Gerhard , Schroeder Melanie , Passerini Stefano , Winter Martin
Published: February 2020

Lithium-ion batteries (LIBs) are becoming more and more important for mobile energy storage devices, with respect to their energy density. For large size applications such as in electric vehicles (EVs) or hybrid electric vehicles (HEVs), both higher energy density and low-cost materials are required also taking environmental friendliness into account. In order to enhance the performance of lithium-ion batteries, researchers and battery-manufacturers are trying to create new electrode materials and new electrolyte compositions. Nevertheless, battery efficiency strongly depends on the electrode engineering and additionally on the production process with the optimization of each individual step.[1,2]

Polyvinylidene fluoride (PVDF) based electrodes on the cathode as well as on the anode side are widely used. One major drawback of PVDF based electrodes is the usage of volatile organic solvents that are often toxic (like N-methyl-2-pyrrolidone (NMP)) and are difficult to dispose at the end of the production process. Alternatively, water soluble natural and/or synthetical based binders have been proposed which also cope the increasing demand of a more environmentally-friendly production process and recycling of LIBs. Processing of active materials for negative as well as positive electrodes is possible using carboxy methyl cellulose (CMC) and/or styrene-butadiene (SBR).[3]

In our study we present the results of our experiments to substitute NMP/PVDF with a water based CMC/SBR binder solution. Moreover, the work comprises the development and adaption of mixing processes, coating techniques, and appropriate drying procedures. To optimize the mixing process for water based slurries we had to figure out ideal substitution grades, mixing ratios between CMC/SBR, and the right pH-value. With the focus on viscosity, mixer types, and shear rates we figured out an optimized slurry configuration for the adaption to our battery pilot plants including the manufacturing of different cell types. Furthermore, the adjustment of coating techniques is one essential issue towards large scale production processes. Nevertheless, we also had to pay attention to the last production step, the drying procedure by the combination of different drying duration and temperatures as well as the adapted drying technique.

This work demonstrates the difficulties and production steps going from lab scale to large scale manufacturing.

We kindly thank the European Regional Development Fund for the funding this project “ProLiBat” (EM-1041H) and also the project partners for support and cooperation.

[1] M. Broussely, J. Power Sources, 81-82 (1999), 140.

[2] X. Zhang, et al., J. Electrochem. Soc., 148 (2001), A463.

[3] Lux, S. F., et al J. Electrochem. Soc., 157.3 (2010), A320-A325.
Lithium Compensation to Mitigate Capacity Fading in High Voltage LiNi0.5Mn1.5O4/graphite Li-ion Cells
Authors: Hu Libo , Zhang Zhengcheng , Johnson Christopher S. , Amine Khalil
Published: February 2020

High voltage cathodes such as the high voltage spinel LiNi0.5Mn1.5O4 have become the spotlight of the Li-ion battery research recently due to their ability to deliver high energy. However, conventional electrolytes based on ethylene carbonate and linear carbonates decompose severely on such high voltage cathodes due to the highly oxidative nature of the fully charged electrode. While efforts have been made to improve the cell performance by developing better electrolytes and additives, none can achieve the high capacity retention seen in the traditional Li-ion batteries with lower voltage limits. In this study, through Li-metal half cells the mechanism of capacity fading in the high voltage Li-ion battery was examined, and the direct cause for the rapid capacity fading on the cathode has been determined to be the active lithium loss due to electrolyte decomposition. The mechanism is similar to what is observed on the graphite anode during the SEI formation process, so prelithiation has been proposed to mitigate the capacity fading in the high voltage LNMO/graphite full cell. Prelithiation of the graphite anodes electrochemically, by physically contact with lithium metal or simply using lithium metal as an anode component have all shown significant improvement in capacity retention for the high voltage LNMO/graphite full cell with conventional carbonate electrolytes at both ambient and elevated cycling temperature. This method has shown even better cycle performance in combination with the previously reported fluorinated high voltage electrolyte.
Investigation into the Solvation of Lithium Anions and the Search for a Connection with Electrode Passivation Behavior
Authors: Cresce Arthur v. , Xu Kang , Russell Selena M. , Urban Nathaniel , Wikner Emily
Published: February 2020

Abstract:

Recently published studies have shown that there is a complex relationship between a lithium ion and its solvent molecules in two-solvent electrolyte systems. Cyclic carbonates like ethylene carbonate are stable in the Li+ solvation sheath while linear carbonates like dimethyl carbonate move in and out frequently, reflecting a difference in coordinating stability with Li+. Because of this bias in Li+ coordinating ability, a correlation can be drawn between the composition of the Li+solvation sheath and the resulting composition of the passivating solid electrolyte interphase that forms on the graphitic anode of a Li-ion battery during the first charge.

We are investigating the solvation condition of the anion in the Li-ion electrolyte system with the goal of identifying a potential correlation between the solvation condition of the anion (including PF6
-, BF4
-, ClO4
-, and TFSI-) and the formation and composition of a cathode passivation layer.

Our previous work indicated that although typical electrolyte anions are poorly coordinated, both PF6
- and BF4
- showed a preference for the low-permittivity linear carbonate ethyl methyl carbonate over the high-permittivity solvent ethylene carbonate. The PF6
-results are summarized in Fig. 1. This result spurred further investigation into the solvation condition of the anion, accomplished using electrospray mass spectrometry, linear voltammetry, x-ray photoelectron spectroscopy, and density functional theory simulations of anion-solvent cluster stability.

We will attempt to show a correlation between the stability of anion-solvent clusters with the composition and formation of the cathode interphase layer.
Verification of O2
-• Formation during Oxygen Reduction Reaction in Li-O2 Batteries
Authors: Cao Ruiguo , Walter Eric , Xu Wu , Nasybulin Eduard , Zhang Ji-Guang
Published: February 2020

Li-O2 battery has been regarded as one of the most promising energy storage systems for the next generation of electrical vehicles and large scale stationary applications.1 It has very high theoretical energy density compared to those of other rechargeable batteries. However, the research for Li-O2 batteries so far is still in its early stage. Significant problems on the stability of electrolyte, cathode and Li anode used in Li-O2 battery still need to be solved before its practical applications.2

In this regards, selection of stable electrolytes, substrates, and efficient catalysts are at the heart of all concerns, without which the rechargeable Li- O2 batteries will not be successful. In order to search stable electrolyte and develop highly efficient catalyst and consequently improve the cycle life of the Li-O2 battery, it is necessary to have a deep understanding on the mechanism of oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) in non-aqueous electrolytes. The mechanism of ORR and OER greatly depends on the activity of catalysts and the types of electrolyte solution environments. Superoxide radical anion (O2
-•) has been proposed as an intermediate during the discharge process, followed by a disproportionation reaction. However, no direct evidence has been found to prove this mechanism because the lifetime of superoxide radical is extremely short at room temperature and it is difficult to visualize the existence of O2
-• by using spectroscopic techniques. Recently, we have studied ORR and OER mechanisms in a non-aqueous Li-O2 battery using ex-situ electron paramagnetic resonance (EPR) technique and have successfully detected the formation of O2
-• during the ORR process (Figure 1). In the charging process, nearly no formation of O2
-•has been found during the OER process. Details of the investigations will be reported and discussed in the presentation.

Acknowledgements

This work was supported by the Joint Center for Energy Storage Research, an Energy Innovation Hub funded by the Basic Energy Sciences, Office of Science of the U.S. DOE. The EPR measurements were performed in the Environmental Molecular Sciences Laboratory, a national scientific user facility sponsored by the DOE’s Office of Biological and Environmental Research and located at PNNL.

1. P. G. Bruce, S. A. Freunberger, L. J. Hardwick and J.-M. Tarascon, Nat Mater, 2012, 11, 19-29.

2. Y. Shao, F. Ding, J. Xiao, J. Zhang, W. Xu, S. Park, J.-G. Zhang, Y. Wang and J. Liu, Adv Funct Mater, 2013, 23, 987-1004.
Development of a High Temperature PEO-Based Li Air Battery
Authors: Balaish Moran , Ein-Eli Yair
Published: February 2020

Li-air battery has the potential of becoming the ultimate power source among all electrochemical energy conversion and storage configurations derived from lithium chemistry. Unfortunately, current configurations, mostly based on a non-aqueous organic liquid electrolyte, suffer from numerous challenges, namely high electrolyte volatility, electrolyte decomposition, low cycle-life, low discharge rates and high discharge/charge over-potential. A very appealing Li-air configuration is obviously one which sees the use of a solid, solvent-free, electrolyte, such as those formed by combining poly(ethylene oxide), PEO, and a lithium salt. Polymer electrolytes are well known promising materials for high energy density rechargeable batteries. Polymer electrolytes poses several advantages over liquid based electrolytes systems, in terms of high chemical, thermal and electrochemical stabilities, all of those are important factors for batteries in number of applications, ranging from portable electronics to electric vehicles. However, wide use of solid polymer electrolyte is still prevented by the decay in ionic conductivity (10-7 to 10-5 S cm-1 at room temperature), resulting from low ionic mobility, high degree of polymer matrix crystallinity, and low degree of charge separation in addition to ion association. We hereby offer a new Li-air battery configuration, based on the well-investigated PEO- lithium salt electrolyte system. The Li-air battery will be comprised of a lithium metal anode, a highly Li+ conductive, oxygen permeable PEO-based, lithium polymer electrolyte and a high surface area carbon air cathode. As opposed to current lithium polymer electrolytes, which operate at room temperature and suffer from low ionic conductivity, the new proposed configuration will operate at a high temperature of 80°c. Above 70°c PEO predominantly exists in the amorphous state, thus a practically useful conductivity is easily achievable in the temperature range of 70-95°c. Our Li-air cell is discharged/ charged at high temperature, thus enabling better kinetics, resulting in high current densities and lower over-potential. The system is studied by electrochemical methods as well as spectroscopic ones.

The results of this work will contribute to the development of practically viable Li-air batteries.
Development of New Anode Composite Materials for Fluoride Ion Batteries
Authors: Rongeat Carine , Munnangi Anji Reddy , Fichtner Maximilian
Published: February 2020

The increasing demand for high energy storage systems has prompted the interest to alternative chemistries for new battery systems, with better performances than currently used Li-ion batteries. Recently, the reversible charge and discharge of a battery based on a fluoride shuttle has been demonstrated [1]. Such a fluoride ion battery (FIB) can theoretically achieve a high energy density, i.e. above 5000 Wh.L-1 for some electrode combinations. This type of batteries is at an early stage of development and large improvements need to be done concerning the performance of the electrodes or of the electrolyte. In the first study, different types of metal fluorides were already tested as cathode (BiF3, CuF2, SnF2 or KBiF4) and Ce metal was used as anode. However, this material, as well as other potential anode materials like La, Ca, Li or Mg, is very sensitive to oxidation, even when stored under argon. We therefore decided to prepare electrode materials in the discharged state to investigate new anode materials, using Bi metal as cathode. We found that it was possible to obtain several cycles of charge/discharge using CeF3 or doped-CaF2 as anode but not when using MgF2. Moreover, the discharge capacities obtained after the initial charge were low. To ensure both electronic and ionic conductivity in the electrodes it is usually necessary to prepare a composite material. Here, only activated carbon was added to CeF3 and doped-CaF2 as these compounds are also good ionic conductors. In the case of MgF2, it was necessary to add also a certain amount of the electrolyte as MgF2 itself shows very poor ionic conductivity. The low performances obtained for this anode composite are thus most likely linked to interfaces issues between the different compounds of the electrode composite. In order to improve the reactivity of the interfaces, a new composite was prepared by adding Mg and MgF2 (the charge and discharge products) to the electrolyte and carbon in the anode composite. Using this new anode composite, it was possible to obtain much better cycling performances with higher charge/discharge capacities and lower polarization. Different characterization techniques were used to understand the reactions occurring when using the different anode material and understand the improvement observed when mixing Mg and MgF2.

[1] M. Anji Reddy & M. Fichtner – J. Mater. Chem. 43 (2011) 17059
UV-Curable Binders for Lithium-Ion Batteries
Authors: Xue Zheng , Zhang Zhengcheng , Amine Khalil
Published: February 2020

Polymer binder is one of the essential components of the composite electrodes used in today’s lithium-ion batteries (LIBs). Due to their chemical inertness, binders are less extensively studied than the active electrode materials in LIB research. Nevertheless, the performance of the entire battery relies heavily on the physical and chemical properties of these “inactive” polymer materials. In a typical electrode making process, a high molecular weight polymer (e.g., PVDF) is mixed with the active materials in the presence of a high boiling point solvent (e.g., NMP) to form a homogeneous slurry. The solvent was then removed from the electrode laminate and recovered―a process that requires significant energy input and capital cost. We recently developed a new process that utilizes ultraviolet (UV) curing to fabricate LIB electrodes, with low molecular weight, UV-curable oligomers serving as the binder precursor. Electrodes with excellent mechanical properties can be prepared using this new process. In the present study, electrode laminates of LiNi1/3Mn1/3Co1/3O2 (NMC) cathode with a polysiloxane acrylate (PSA) oligomer-based binder were prepared and evaluated electrochemically in NMC/Li and NMC/graphite cells. The cycling and C-rate performance of these UV-cured electrodes were comparable to that of conventional PVDF-based electrodes. The main advantage of this new approach is its high production speed with lower energy input and less solvent consumption than in traditional processes. Furthermore, a wide range of functional, reactive oligomers may potentially be utilized as binder precursors in this UV-curing process, allowing for easy tuning of the binder structure to deliver electrodes with desired physical and electrochemical properties.
Theoretical Study of the Morphological and Structural Characteristics of a Hydrated Anion Exchange Membrane Used in Alkaline Fuel Cells Using DFT
Authors: Castañeda Ramírez Sergio , Ribadeneira Paz Rafael Esteban
Published: February 2020

Anion-exchange membrane fuel cells (AEMFC) have great potential of commercialization at low cost for their use in automotive transportation, portable batteries and power generators with respect to similar technologies as the proton-exchange membrane fuel cells (PEMFC) due to: a) better kinetic characteristics both for the oxygen reduction reaction as for the hydrocarbon oxidation reducing costs of catalysts, b) lower fuel crossover from anode to the rest of the device, c) simpler water management and d) reduced degree of corrosion [1–3].

Despite the mentioned advantages, the polymeric materials used as electrolytes show low conductivity and chemical stability values, which limit respectively the efficiency and durability of the fuel cell, and as experimentally these factors have not been optimized yet, it is important to understand the related physicochemical phenomena, being the anion transport primordial [1,2,4,5]. Nevertheless, the characteristics of the mechanisms associated with that process are not well known, particularly the Grotthuss mechanism, that is considered to contribute mostly to the hydroxyl ion mobility [1,4].

In order to understand this mechanism and to improve the description of the ion mobility in AEMFCs is mandatory to carry out a rigorous theoretical study, for which the first step is to describe the appropriate structure of a particular anion exchange membrane. So, the aim of the present research is study the morphological and structural characteristics of the quaternized polystyrene-block-poly(ethylene-ran-butylene)-block-polystyrene homogeneous membrane synthetized by Qing Hua Zeng and co-workers [6] for different humidification values by means of density functional theory (DFT) techniques, considered the most suitable in terms of prediction and accuracy since there are not almost theoretical studies about structural and morphological characteristics of anion exchange materials used in AEMFC.

With the results obtained, the idea is evaluate the potentiality of DFT techniques to obtain accurate structures for polymeric membranes and use the one generated for future investigations about the physicochemical characteristics of the Grotthuss mechanism for hydroxyl ions in membranes used in AEMFCs, in order to determine the best morphological and structural characteristics of this type of materials from a theoretical approach.

References:

[1] G. Merle, M. Wessling, K. Nijmeijer, J. Memb. Sci. 377 (2011) 1.

[2] E. Antolini, E.R. Gonzalez, J. Power Sources 195 (2010) 3431.

[3] R. Slade, J. Varcoe, Solid State Ionics 176 (2005) 585.

[4] K.N. Grew, W.K.S. Chiu, J. Electrochem. Soc. 157 (2010) B327.

[5] B. Pivovar, 2011 Alkaline Membrane Fuel Cell Workshop Final Report, 2012.

[6] Q.H. Zeng, Q.L. Liu, I. Broadwell, A.M. Zhu, Y. Xiong, X.P. Tu, J. Memb. Sci. 349 (2010) 237.
Li Diffusion in Rare-Earth Metal Doped Battery Materials
Authors: Grosse Frank
Published: February 2020

One of the key elements determining the performance in Li-ion batteries is the diffusion. All solid-state batteries require fast ionic diffusion in the electrolyte but equally important in the anode and cathode. The electrolyte is required to be electronically non-conducting, the opposite is true for anode and cathode. Various compounds are currently investigated.

It is intuitively clear that by widening the Li-ion diffusion channels the activation barrier will be reduced leading to faster diffusion. The lattice parameter can be increased by partially replacing host atoms by impurities with a larger atomic radius. With this strategy in mind, I) the influence of the diffusivity on the lattice parameter is studied employing density functional theory. II) The thermodynamic stability of rare-earth metal atoms as impurities in existing battery materials is calculated in conjunction with the Li diffusion.

I) The influence on the lattice parameter is evaluated in two ways. Changing the lattice parameter by introducing impurities or alloying similar materials not only changes the lattice parameter but simultaneously introduces disorder along the Li-ion diffusion pathways. Therefore, changing only the lattice parameter artificially by applying an external strain allows disentangling the contributions from the lattice expansion vs. the disorder effect. At the example of Li diffusion in rare-earth oxides it is shown that the activation energy can be reduced by increasing the lattice parameter in agreement with experiments [1].

II) The thermodynamic stability of rare-earth metal atoms in materials suggested as cathode materials like spinel LiMn2O4 and LiCoO2 is calculated. The influence on the Li diffusion due to the introduced lattice distortion and reduced symmetry is discussed. A coarse-grained diffusion model on the basis of the DFT data is introduced containing the relevant changes in the local activation energies due to the presence of the rare-earth metal impurities. The numerical evaluation of the diffusion is carried out by kinetic Monte Carlo simulations.

Acknowledgements: This work was supported by the Leibniz-Gemeinschaft under the project No. SAW-2011-PDI-230.

[1] S. Tamura, A. Mori and N. Imanaka (2006). Solid State Ionics, 177(26-32), 2727–2730.
Effects of Particle Size and Size Distribution on the Percolation Behavior of Composite Proton Conducting Solid Oxide Fuel Cells Cathode
Authors: LI Meiling , NI Meng , Shen Geoffrey Qingping
Published: February 2020

The cathode is the key in improving the performance of solid oxide fuel cells (SOFCs) at an intermediate temperature (IT). High performance cathode requires not only large amount of reaction sites, but also efficient transport of gases, electrons and ions, which are characterized by the percolation properties of the cathode. In this paper, the effects of cathode material properties and microstructures on percolation behavior of a composite SOFC cathode are analyzed by a 3D numerically morphological dilation method with controlling contact angles between two types of particles. The proposed model is validated by comparing the present simulation results with data from our previous kinetic Monte Carlo (KMC) simulations. The model is used for calculating the effective conductivity and percolation behaviors of proton-conducting SOFC (H-SOFCs) cathode. Detailed simulations are conducted under different parameters (mean particle radius of composite cathode, volume fraction of electrode and electrolyte materials, bulk material conductivities) to investigate their effects on the important effective ionic conductivity and percolation behavior of the cathode at an IT. The results could help design high performance H-SOFC electrodes.
Comparison between Kinetic Model and Equilibrium Model in Methane Fed SOFCs with Internal Reforming Reaction
Authors: Qiong Sun , Ni Meng
Published: February 2020

SOFC is a clean and promising energy conversion device that has the advantage of fuel flexibility over other types of fuel cells. In the methane fed SOFCs with internal reforming reaction, direct internal reforming (DIR) reaction and water gas shift reaction (WGSR) occur in anode. To model internal reforming SOFCs, kinetic model and equilibrium model are normally utilized through reviewing previous researches. In order to investigate a more effective model to simulate the processes of electrochemical reactions, the chemical reactions and gas diffusion in the internal reforming SOFCs, comparison between kinetic model and equilibrium model will be conducted. The research results may provide a theoretical basis for future modeling in internal reforming SOFCs.

Key words: SOFC, Direct Internal Reforming (DIR), Kinectic model, Equilibrium model
Dynamics of Deposited Li2O2 Clusters on Cathode Surface in Li-O2 Battery Investigated By First-Principles Molecular Dynamics
Authors: Yamamoto Wataru , Alam Md. Khorshed , Takaba HIromitsu
Published: February 2020

In recent years, Li-O2 battery has received a great attention as a battery with high capacity and energy density. However, further studies are needed for the use of practical application to solve the issues must be overcome, such as lithium dendrites, side reactions of electrolyte, a blocking effect of diffusion path of oxygen and a corrosion of carbon. In this study we focus on, among from these issues, a blocking effect of diffusion path of oxygen in the cathode, which is the most important issue to realized the high capacity. Discharge products would inhibit oxygen diffusion in a cathode. Main discharge product is Li2O2. In this study we also focus on a dynamics of Li2O2. Li2O2 is generated from electrochemical reaction and will cover with the surface of the cathode resulting in the termination of further electrochemical reaction. Thus, the elucidation of dynamics of Li2O2 cluster on cathode surface is a key problem for the better understand of the life time of battery and the theoretical design of more improved Li-O2 battery.

The electrical conductivity of Li2O2 is also influenced on the life time of the battery. There has been reported that a hole forming by the defect of Li palys a important role in the electrical conductivity of Li2O2. In this study, we model the formation of deposited Li2O2 layer as well as the forming process of the crystal defect, from the point of view of diffusion of Li2O2 cluster on the cathode surface. We calculate the sintering and diffusion processes of the discharge product Li2O2 on the carbon surface using a first-principles molecular dynamics method. We also examine how Li2O2 is deposited on the carbon surface. As a result, it deposited on the cluster shape up to the thickness of 3 " at 300 K. It is observed that the band gap of the Li2O2 is related to the thickness and it rapidly increases when it exceeds the 8 ". Diffusivity decreases in proportion to the increase in the size of Li2O2 cluster. Calculated diffusion coefficient of Li2O2 is revealed to the effect on the electrical conductivity of Li2O2. From these results, we investigate the effect of electrical conductivity of Li2O2 on the discharge curve analyzing by a numerical simulation. Conductivity shows little effect on the discharge curve. Therefore, It is concluded that a pore blocking is major factor of capacity of Li-O2 battery. This is the first study will be able to provide a breakthrough for the development of better Li-O2 battery.
Performance of MIEC Cathodes in SOFC Stacks Evaluated by Means of FEM Modeling
Authors: Geisler Helge , Kromp Alexander , Weber André , Ivers-Tiffée Ellen
Published: February 2020

Solid oxide fuel cells (SOFC) are connected in series to stacks by metal interconnectors (MIC). Hereby, the potentially high performance of anode-supported cells (ASC) is significantly reduced. [1,2]. Conclusively, gas diffusion polarisation at the mixed conducting cathode contributes close to the sum of all ohmic losses to the overall polarization, both controlling stack performance.

In order to investigate the matter further, a 2D FEM repeat unit model was developed, which accounts to ohmic and polarisation loss on a stack level [3]. In the model the physical processes i) gas diffusion in the porous electrodes, ii) electric /ionic conduction in the electrodes and electrolyte as well as iii) the electrochemical electrode reactions are incorporated. Electrode microstructure is implemented via 3D reconstruction of FIB-tomography images [5,6]. Electrode kinetic parameters are determined via EIS evaluations [4]. Performance predicted by the model was validated with the help of current/voltage-characteristics measured on high performance anode supported cells.

The model calculations demonstrate the interdependence of cathode material parameters (thickness, porosity, conductivity, electrode kinetics) and MIC-design, and widen the understanding on their influence on stack performance. The results show i) that an optimal MIC-design depends on the cathode material parameters and ii) a well-chosen cathode thickness increases the overall power output.

[1] L. Blum, W. A. Meulenberg, H. Nabielek, R. Steinberger-Wilckens, Worldwide SOFC Technology Overview and Benchmark, International Journal of Applied Ceramic Technology2 pp. 482-492 (2005).

[2] M. Kornely, A. Leonide, A. Weber, E. Ivers-Tiffée, Journal of Power Sources
196 (17), pp. 7209-7216 (2011).

[3] H. Geisler, M. Kornely, A. Weber, E. Ivers-Tiffée, ECS Trans.
57, pp. 2871-2881 (2013).

[4] A. Leonide, Y. Apel, E. Ivers-Tiffée, ECS Trans.
19, pp. 81-109 (2009)

[5] J. Joos, T. Carraro, A. Weber, E. Ivers-Tiffée, J. Power Sources
196, pp. 7302-7307 (2011).

[6] J. Joos, M. Ender, I. Rotscholl, N. H. Menzler, E. Ivers-Tiffée, J. Power Sources
246, pp.819-830 (2014)
One-Step Flash Sintering of Solid Oxide Fuel Cells
Authors: Guan Xiaofei , Francis John S , Pal Uday Bhanu , Gopalan Srikanth
Published: February 2020

Solid oxide fuel cells (SOFCs) are ideally suited for environmentally benign conversion of chemical energy in hydrocarbons to electricity. While medium scale SOFC power systems in the hundreds of kWe have been demonstrated, larger scale application of such systems have been hobbled by still too high cost. Reducing the manufacturing costs of single cells is an important goal as one step towards commercialization. Previously, we demonstrated a simplified process to manufacture the complex multilayer architecture of anode supported single cells in a single high temperature firing step, after deposition of the anode active layer, electrolyte, cathode active layer, and cathode current collector layers serially by screen printing on to an anode substrate fabrication by a process known as high shear compaction. In this paper, we present a novel manufacturing process in which the basic green-state cell is fabricated using the same steps as before, but in which the high temperature conventional sintering step is replaced by a technique known as flash sintering which reduces time at temperature by up to an order of magnitude, thereby resulting in significant savings in time and electrical energy expended. We present details of this new process, cross-sectional microstructures of cells fabricated using this technique, and compare the power densities of the cells processed by flash sintering with the prior co-fired process.
(Invited) Towards a Fundamental Understanding of the Cathode Degradation Mechanisms
Authors: Wachsman Eric D. , Huang Yi-Lin , Pellegrinelli Christopher , Taillon Joshua A. , Salamanca-Riba Lourdes G.
Published: February 2020

While impressive solid oxide fuel cell (SOFC) performance has been achieved, durability under “real world” conditions is still an issue for commercial deployment. In particular cathode exposure to H2O and CO2 results in long-term performance degradation issues. Therefore, we have embarked on a multi-faceted fundamental investigation of the effect of these contaminants on cathode degradation mechanisms in order to establish cathode composition/structures and operational conditions to enhance cathode durability Using a dual Focused Ion Beam (FIB)/SEM) we are quantifying in 3-D the microstructural changes of cathode before and after the onset of cathode performance degradation. This includes changes in TPB density, phase-connectivity, and tortuosity, as well as tertiary phase formation. This is linked to heterogeneous catalysis methods to elucidate the cathode oxygen reduction reaction (ORR) mechanism to determine how H2O and CO2 affect the ORR as a function of temperature, time, and composition. By use of in-situ
18O-isotope exchange of labeled contaminants we will determine whether oxygen incorporated in the lattice of LSM and LSCF, and their composites with YSZ, originated from ambient O2 or the contaminant as well as intermediate adsorbed species and mechanisms that lead to degradation. The results will be used to develop a cohesive and overarching theory that explains the microstructural and compositional cathode performance degradation mechanisms.
Proton-Conducting Ce0.9Mn0.1P2O7 Composite Electrolytes for Low Temperature Ceramic Electrolyte Fuel Cells
Authors: Singh Bhupendra , Kim Ji-Hye , Jeon Sang-Yun , Park Jun-Young , Song Sun-Ju
Published: February 2020

Cerium pyrophosphate based solid state proton conducting materials with ionic conductivity >10-2 S cm-1 in 100-250 oC range have immense importance in fuel cells.1-5 In this work, Ce1-xMnxP2O7 (CMP) (x=0.05, 0.075, 0.1, 0.125 and 0.15) composite electrolytes are synthesized by two-step slow digestion method with different P/(Ce+Mn) molar ratio.4 The CMP samples with high phosphate content become denser on sintering. The variation of ionic conductivity with temperature is studied in dry and humidified air for the potential application of CMPs as electrolytes in proton-conducting ceramic electrolyte fuel cells. Among various CMP samples, CMP-100-2.7P (i.e. Ce0.9Mn0.1P2O7 with P/(Ce+Mn)=2.7) shows maximum conductivity of 6.54X10-6 S cm-1 at 450 oC in dry air and 1.78X10-2 S cm-1 at 170 oC in humidified air (pH2O= 0.12 atm). The ionic conductivity of CMPs increases with the increasing pH2O and CMP-100-2.7P shows maximum conductivity of 2.24X10-2 S cm-1 at 170 oC in pH2O=0.16 atm.

Figure. (a) SEM images of fractured section of 400 oC sintered pellets of Ce0.9Mn0.1P2O7 samples with different initial P/(Ce+Mn) ratio; Temperature dependence of ionic conductivity of various CMP samples with different dopant concentration in (b) dry air and (c) humidified air (pH2O =0.12 atm) condition.

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