bluuebunny/crossref_metadata_2025 huggingface dataset:
Advanced Proton Conducting Ceramic Cell as Energy Storage Device
Authors: Marrony Mathieu , Dailly Julian
Published: February 2020

The last decade reveals the high potential of Solid oxide cells (SOC) as hydrogen battery storage operating to the demand either under fuel cell (concept gas-to-power) or electrolysis (concept power-to-gas) profiles. Such types of ceramic-based cells usually operate beyond 750°C in order to keep reasonable electrical performances and reliability of the whole electrochemical device. Now, one of the main challenge is to reduce the operating temperature in order to limit ageing parameters (Cr contamination, metal corrosion…) and improve energy efficiency while promoting cheaper materials and system processing. Actually, O2
--conducting SOC suffers to an insufficient activity of the oxygen electrode and electrical performances at lower operation temperature.

In such context, Protonic Ceramic Cell (PCC) technology can overcome such technical hurdle by operating below 700°C. Protonic Ceramic Cells are benefit from the presence of the water produced/consumed at the air electrode side, avoiding the dilution of the fuel. The ageing and chemical reactivity of materials should be less critical than these observed at higher temperature. Proton Conducting Ceramic Cell is now widely investigated for a variety of applications, in particular fuel cell, steam electrolysis and hydrogen separation but such technology has to face to the lack of Technology Readiness Level (operating parameters definition, durability, dimensioning) for a viable way of market.

During the last years, our group validated promising pioneer promising electrical performances (400-500 mW.cm²) and reliability of few hundred hours under dynamic fuel cell power demand profile below 700°C [1-3]. Here is discussed the evaluation of advanced PCC materials and manufacturing processes under electrolysis and reversible Fuel cell / electrolysis cycles modes. Finally, more than 3500 h of long-term testing were validated under various function profiles (as electricity producer or as hydrogen producer) with limited electrical degradation (cf. Figure 1). Such highlights pave the way to the use of PCC technology as high efficient energy storage candidate .

Figure 1
Quantitative Defect Chemistry Analysis Of (La1-xCax)yFeO3±δ
Perovskite
Authors: Darvish Shadi , Zhong Yu
Published: February 2020

The defect chemistry of (La0.8Ca0.2)0.95FeO3±δ is analyzed using the La-Ca-Fe-O quaternary thermodynamic database. The quantitative Brouwer diagrams for LCF are developed in different temperatures and oxygen partial pressure. The detailed analysis of the charge disproportionation behavior and the electronic conductivity is carried out with the compound energy formalism model by applying the CALPHAD approach. The electronic conductivities are compared with the existing experimental measurements. The fundamental thermodynamic and kinetic analysis has been carried out to understand the factors affecting the experimental data and the thermodynamic database accuracy.
Ba0.5Sr0.5Co0.8Fe0.2O3-δ / Gd0.1Ce0.9O2-δ Core/shell Nanofiber Via One-Step Electrospinning for Cathode of LT-SOFCs
Authors: Kim Chanho , Jang Inyoung , Kim Sungmin , Yoon Heesung , Paik Ungyu
Published: February 2020

The cathode of solid oxide fuel cells (SOFC) is highly related with reduction of oxygen which is the critical factor for whole performance. In order to exert high power, research for improving the cathode property is essential. Enhancing the performance by modifying the nanostructure of cathode has limitation such as collapse of structure during the ceramic process at high temperature. In this study, Gd0.1Ce0.9O2-δ (GDC) embedded Ba0.5Sr0.5Co0.8Fe0.2O3-
δ (BSCF) nanofiber which has advantages such as charge transfer, large reaction site was investigated for cathode SOFC. One step electrospinning for synthesizing heterogeneous nanofiber was employed with solution contains BSCF particles and Gd(NO3)3 ,Ce(NO3)3 in dimethylformamide(DMF). GDC nanoparticles which has diameter of 50-100nm are embedded on the surface of BSCF nanofiber which has diameter of 400nm after sintering at 1000 oC. Ideal structure for cathode which facilitates efficient path for electron and ion was fabricated.
Fabrication of 100 Centimeter Square Metal-Supported Solid Oxide Fuel Cell Using Thermal Plasma Technique
Authors: Yang Sheng-Fu , Hwang Chang-Sing , Tsai Chun-Huang , Chang Chun-Liang , Wu Ming-Hsiu , Fu Cheng-Yun , Lee Ruey-Yi
Published: February 2020

In this study, the large-scale mold for compression molding process is prepared and a compression load of 120 ton is applied to form a porous alloy specimen with dimension of 12×12×1.2 cm. The carbon is used as pyrolyzable filler in the period of manufacturing processes in order to produce porous interconnected networks of molybdenum (Mo)-containing nickel (Ni)-based alloy. The specimens are sintered in hydrogen at the temperature of 1250°C to obtain porous alloy substrate. The flexural strength of porous alloy supporting component is measured in this work. The strength of porous alloy substrate (Sintered at 1250°C) in three-point flexure at 25°C and 750°C are 188 MPa and 76.5 MPa, respectively. Metal-supported solid oxide fuel cells (MS-SOFCs) are fabricated by thermal plasma spraying technique and the anode (Ce0.55La0.45O2-δ -NiO,LDC-NiO), electrolyte (La0.8Sr0.2Ga0.8Mg0.2O3-δ, LSGM) and cathode (Sm0.5Sr0.5CoO3-
δ,SSC) functional layers are deposited onto porous alloy substrate. The 10×10 cm2 MS-SOFC with effective electrode area of 81 cm2 shows the open circuit voltages is 1.09 V at 700°C. The measured maximum output power densities (@0.76V) of this cell has reached 588 mW/cm2 at 700°C by employing hydrogen as fuel and air as oxidant.
A New Insight into the Oxygen Reduction Reaction on High Performance Cation-Ordered PBCO Perovskite as IT-SOFC Cathode
Authors: Zhang Nan , Li Wenyuan , Berry David , Surdoval Wayne , Shekhawat Dushyant , Liu Xingbo
Published: February 2020

The advantage of double perovskite materials (cation-ordered) over single perovskite materials (cation disordered) have been widely reported in SOFC cathode studies. However, the effect of the different phase structures of double perovskite on the electrode performance has not been investigated. In this work, tetragonal and orthorhombic PrBaCo2O5+
δ (PBCO) perovskite powders are synthesized through controlling of the sintering atmosphere and temperatures. X-ray diffraction and scanning electron microscopy are used to examine the phase structure and morphology. The bulk diffusion (D) and surface exchange (k) coefficients were characterized by electrical conductivity relaxation (ECR) test on dense PBCO samples. The electrode performance is evaluated by electrochemical impedance spectroscopy (EIS) on symmetric cells. It is found that the tetragonal structure displays smaller polarization resistance than that of the orthorhombic structure. Polarization resistance value at 650 ℃ are 0.078 Ω·cm2 and 0.10Ω·cm2 respectively. This tendency is coincident with the higher D and k values obtained from ECR for the tetragonal structure. Oxygen incorporation is suggested as the rate-determining step in the oxygen reduction reaction based on the analysis of EIS and D&k data. The existence of interstitial oxygen in the tetragonal structure is proposed to be responsible for this improvement in the electrode performance.
The Electrochemical Performance of LSM with A-site Non-Stoichiometry under Cathodic Polarization
Authors: Liu Jian , Yu Yang , Yang Tao , Ozmen Ozcan , Finklea Harry , Sabolsky Edward M. , Abernathy Harry , Ohodnicki Paul R , Hackett Gregory A
Published: February 2020

The activation behavior of a LSM based-cathode in the SOFC is characterized by a rapid reduction in the electrode polarization resistance after cathodic current passage treatment. This activation behavior has been attributed to mechanisms that either enhance the kinetics of oxygen reduction or remove impediments from the oxygen reduction mechanism. Due to the sensitivity of the activation process to the operation history, a comprehensive study was carried out to reveal the relationship between the activation conditions, the steady state cathode performance and the long term stability. This work demonstrates the application of a two electrode configuration half-cell operated for the impedance analysis of LSM-based electrodes. The effects of current density and overpotentials on the activation behavior of LSM based electrode were investigated. The impacts of temperature and oxygen partial pressure to the activation process and final performance are also discussed. Long term degradation test of LSM electrodes were carried out on both half-cells and full cells with various activation processes. Numerical simulation of the LSM-based cathode was conducted with a multi-step oxygen reduction reaction (ORR) mechanism for a better understanding of the nature of the activation process. The results are of great relevance as the electrode performance depends on not only the fabrication but also on the initial break-in procedure.
Phase Stability of Lanthanum Nickelate (LNO) in LNO-Doped Ceria Composite Cathodes
Authors: Gopalan Srikanth
Published: February 2020

Phase equilibria of La2NiO4+δ: LaxCe1-xO2-δ (LNO: LDC) composites (sintered at 1300°C) was studied using X-ray diffraction (XRD). The variables considered in these experiments were the dopant concentration in the ceria phase (0.2<x<0.48) and volume fractions of LNO in the composite cathode. This system has been previously evaluated and the sub-solidus phase equilibria between NiO, La2O3, and CeO2 at 1200°C was revisited, and studied at 1300°C and 800°C. A thermodynamic rationale was used to re-engineer the LNO: LDC composites which stabilized the LNO phase in the composite electrode. Elemental analysis via wavelength dispersive X-ray spectroscopy (WDS) confirmed the chemical composition of the stable phases in the composites. Measurements of the coefficient of thermal expansion (CTE) of LNO: LDC composites as a function of LNO volume fraction provided further evidence of the stability of LNO and LDC (for x=0.4). Finally, we have also performed electrical conductivities of La2NiO4+δ: La0.4Ce0.6O2-δ composites as a function of LNO volume fraction between 600 and 800°C in air. The electrical conductivity of the composites was analyzed via the resistive network approach. Based on these experiments, a window of composition is provided for stable, high performance cathode compositions in this system.
Advances in Solid Oxide Fuel Cells: Review of Progress through Three Decades of the International Symposia on Solid Oxide Fuel Cells
Authors: Minh Nguyen , Mizusaki Junichiro , Singhal Subhash C.
Published: February 2020

Solid oxide fuel cell (SOFC) technology has made significant progress in the past 30 years and is currently in the early commercialization stage. The progress of the technology can be seen clearly through review of the papers and presentations at the biennial International Symposium on Solid Oxide Fuel Cells series initiated in 1989. This paper details the growth and evolution of the Symposium series as the technology progressed, and highlights key advances in materials development, understanding of electrode reactions and chemical interactions, and design, performance, durability and operation of SOFC single cells, multi-cell stacks and power systems as documented in the Symposium proceedings.
In situ Studies of Phase Evolution in (Pr1-xNdx)2NiO4 Electrodes with Various Interlayer Chemistries
Authors: Dogdibegovic Emir , Alabri Nawf Saif , Wright Christopher J. , Hardy John S , Coyle Christopher A , Horlick Sam , Guan Wanbing , Stevenson J. W. , Zhou Xiao-Dong
Published: February 2020

Nickelate (e.g. Pr2NiO4) exhibits high activity towards the oxygen reduction reaction over a wide temperature range (600 - 900 oC), which makes it a promising candidate as an advanced cathode for solid oxide fuel cells. However, a phase transition occurs in Pr2NiO4 during cell operation, following: Pr2NiO4 à Pr6O11 + Pr3Ni2O7. As a result, the quantification of the degree of phase transformation becomes necessary to understand the structure-electrochemical property relationship. In this presentation, we report our recent work on (1) replacing the oxide current collector with a gold metal grid, which enables the cathode to expose to the x-ray beam. The x-ray analysis was performed at room temperature and (2) utilizing in situ capability to study the kinetics and mechanisms of phase evolution and establishing the relationship between high-temperature structures and the electrochemical performance. Finally, we will compare the XRD results acquired from room temperature with these in situ studies.

This material is based upon work supported by the U.S. Department of Energy under Award Number DE-FE0023475.
Effects of H2O and CO2 Corrosion on Ba0.9Co0.7Fe0.2Nb0.1O3-δ Cathode
Authors: Yang Zhibin , Wang Jingle , Wang Yuhao , Liu Yahui , Han Minfang
Published: February 2020

With the development of SOFC technology, stability has been more and more concerned because of its necessity in SOFC commercialization. In cathode side, contaminations such as CO2 and H2O existing in air are likely to influence the stability of SOFC in long-term operation. In this work, the effect of CO2 and H2O corrosion on high performance Ba0.9Co0.7Fe0.2Nb0.1O3-δ (BCFN) cathode are studied through XRD measurements, conductivity and electrochemical impedance spectroscopy (EIS) analysis. The XRD results show that even in the atmospheres of 3%CO2-3%H2O-96%Air, the chemical reaction is happened and BaCO3 is generated. And the conductivity of BCFN reduces obviously in the presence of CO2 and H2O. Compare with the single factor of CO2 or H2O, the polarization resistance of BCFN electrode increase obviously on the co-corrosion of CO2 and H2O, which declares that the co-effect of H2O and CO2 plays an importance role in the corrosion process on BCFN cathode.
Fabrication of La1-XSrxCoO3–Sc2O3–ZrO2 Composite Cathode By Electrochemically Assisted Deposition for Solid Oxide Fuel Cells
Authors: Lee Seung-Bok , Rehman Saeed ur , Lee Jong-Won , Song Rak-Hyun , Lim Tak-Hyoung , Park Seok-Joo , Hong Jong-Eun
Published: February 2020

We developed a novel method for the fabrication of La1-xSrxCoO3–Sc2O3–ZrO2 (LSC–SSZ) composite cathode for solid oxide fuel cells (SOFC) via electrochemically assisted deposition of La1-xSrxCoO3 (LSC) into a porous Sc2O3–ZrO2 (SSZ) scaffold. To do so, a highly porous SSZ scaffold was fabricated by screen printing an SSZ ink containing 30 wt % PMMA pore-former onto a dense SSZ electrolyte layer of a NiO–SSZ|SSZ half-cell. The porous SSZ scaffold was made electrically conductive for the electrodeposition process by carbon deposition in a flowing N2/ethylene environment at 800 °C. Subsequently, lanthanum, strontium and cobalt were simultaneously deposited into the porous carbon coated SSZ scaffold by electrochemically assisted deposition involving nitrate reduction and hydroxide precipitation processes. To form an LSC perovskite phase, the button cells were heat treated in air at 800 °C for 5 h. The LSC–SSZ composite cathode functional layer was characterized by the SEM, EDS and XRD analysis. The results indicated a formation of LSC into the porous SSZ scaffold in the form of dendrites initially and as the deposition time was increased the LSC dendrites were thickened and finally formed a dense layer on the top of SSZ scaffold. The deposition was found to be uniform inside the SSZ scaffold up till the cathode/electrolyte interface. The electrochemical testing of button cells showed a high performance, which indicated that the developed technique is promising and it should be further explored to fabricate high performance SOFCs.
Applications of the Glycine Nitrate Combustion Method for Powder Synthesis on the LSGM-based Electrolyte-Supported Solid Oxide Fuel Cells
Authors: Chen Yu-Ming , Lin Tai-Nan , Liao Ming-Wei , Kuo Hong-Yi , Yeh Chun-Yen , Kao Wei-Xin , Yang Sheng-Fu , Wu Kuan-Ting , Ishihara Tatsumi
Published: February 2020

Solid oxide fuel cells (SOFCs) are recognized as environmentally friendly, highly efficient devices, and alternatives to conventional energy conversion systems. Typical material design used is the YSZ-based cell consisted of NiO-YSZ and LSM as anode and cathode, with a dense electrolyte of YSZ. When considering the use of hydrocarbon fuels, carbon deposition has been observed as major failure issue. Ce0.6Mn0.3Fe0.1O2 (CMF) has been studied recently because of the high tolerance against coke deposition and it also exhibited high catalytic activity. In this work, Cu-doped CMF powders were synthesized by glycine nitrate combustion process (GNC). The structure, microstructure, conductivity, coefficient of thermal expansion properties were investigated. Cu-doped CMF powders were utilized as anode material in Sr- and Mg-doped LaGaO3 (LSGM)-based electrolyte-supported solid oxide fuel cell for power performance test. The cell with structure of (Cu-doped CMF) | LSGM | LSCF was operated from 600 to 800 °C with humidified H2 as a fuel and ambient air as oxidant to evaluate the electrochemical properties.

keywords：Ce0.6Mn0.3Fe0.1O2, glycine nitrate combustion process, Sr- and Mg-doped LaGaO3
Study on Nickel Morphological Change at Active Three-Phase-Boundary in Solid Oxide Fuel Cell Anode Using Patterned Nickel-film Electrode
Authors: Jiao Zhenjun , Shikazono Naoki
Published: February 2020

Patterned nickel-film anode was used in this study to investigate the local morphological changes of nickel during discharge at TPB three-phase-boundary in solid oxide fuel cell anode. Compared to conventional nickel-yttria-stabilized zirconia composite cermet anode, patterned nickel-film anode has the advantages of direct observations at nickel-yttria-stabilized zirconia interface and at three-phase-boundary so that the local morphological changes of nickel can be characterized by scanning electron microscopy. The phenomena of enhanced nickel wettability on yttria-stabilized zirconia surface and nickel spreading on yttria-stabilized zirconia surface at active three-phase-boundary during discharge operation were observed and explained by a proposed model based on the modification of local nickel surface tension by discharge. The nickel-film anode performances and local nickel morphological changes at three-phase-boundary before and after discharges with different conditions were analyzed. The influences of discharge time and overpotential in discharge on local morphological change of nickel and their influences on nickel-film anode performances were also investigated.
Robust Ni-based Anode Deposited with La0.6Sr0.4FeO3
-δ

for Direct Methane-Fueled SOFCs
Authors: Zhang Yongliang , Fan Hui , Han Minfang
Published: February 2020

Conventional Ni-YSZ anodes suffer from carbon deposition when methane is used in SOFCs as fuel. In this work, a new strategy was proposed to solve the problem, that the anode was modified by SrFe1.5Mo0.5O3 nanoparticles using infiltration method. It was found that, when humidified CH4 was used as fuels, SFM@Ni-YSZ anode-supported cell shows lower power output compared with the Ni-YSZ anode-support cell. However, the infiltrated SFM has a positive impact on the long term stability of the anode. No significant degradation was found in 100hrs operation at 0.15A/cm2 and 750oC, indicating the excellent carbon deposition resistance of SFM@Ni-YSZ anode. Furthermore, it was found that the amount of infiltrated SFM was related to the anode performance, which gives a way to gain a compromise between SOFC performance and carbon deposition resistance.
Novel Ceria-Lanthanum/Zirconium (LDC/ZDC/ZLDC) Based Anodes with the Incorporation of Copper Running over Biogas Fuel Cells
Authors: Iftikhar Asia
Published: February 2020

Biogas is a promising fuel for many clean energy applications and have propitious effect on the environment as well. Hydrocarbon fuels open up new path for the electric power generation technology in replacing conventional combustion devices with renewable sources e.g., biofuel. Active and stable anode nano catalysts are utilized to achieve sufficient advantages for solid oxide fuel cells running on biogas. In this paper, a series of ceria based anodes NixLiyCu(1-x-y)-LDC/ZDC/ZLDC (x=0, 0.2, 0.4, 0.6, 0.8, y=0.2) are synthesized via ball milling route, while nanocatalysts NixLiyCu(1-x-y) (NLC) and LDC/ZDC/ZLDC are prepared by glycerol sol-assisted synthesis and simple co-precipitation method respectively . These nanocatalysts are characterized using x-ray diffraction (XRD) to study its structural properties and thermal analyses are carried out by thermo-gravimertic analysis (TGA) and BET. To study its morphology, scanning electron microscopy is done to calculate its particle size and porosity. The performance of the solid oxide fuel cell with biogas has been studied with a 50% composition of methane. The short term sable performance has been observed without any carbon formation. Key words: ceria, lanthanum, zirconium, anode catalysts, biogas
Influence of Pre-Oxidation on Dual Atmosphere Effect on AISI 441 Interconnects for Solid Oxide Fuel Cell Applications
Authors: Goebel Claudia , Alnegren Patrik , Faust Robin Leonard , Svensson Jan-Erik , Froitzheim Jan
Published: February 2020

Interconnects are an integral part of solid oxide fuels cells (SOFC) and, even when ferritic stainless steel is used, their contribution to the overall stack cost is still substantial. Stainless steels that are produced in large volumes such as AISI 441 are particularly attractive from a cost perspective. However, in our previous work, we have shown that this material suffers from severe corrosion in dual atmosphere exposure at 600 °C typical for Intermediate Temperature-SOFC (IT-SOFC) applications. We have seen a beneficiary effect of pre-oxidation and will, in the present work, closely examine this effect. By varying pre-oxidation parameters such as length and location (anode vs. cathode side) of the oxide layer, we were able to clarify the importance of pre-oxidation. Furthermore, we see a correlation between the length of pre-oxidation, and therefore the thickness of the oxide layer, and the onset of breakaway oxidation. This correlation is expected to allow for accelerated life time testing with respect to dual atmosphere corrosion.

For our studies we chose five different pre-oxidation times: 0 min, 11 min, 45 min, 180 min and 280 min. The dual atmosphere exposure was conducted at 600 °C and the exposure was interrupted after 24 h, 168 h and 500 h and photographs were taken of the air facing side of each steel sample. By means of the photographs, we can clearly correlate length of pre-oxidation with onset of breakaway. Our findings are further supported by Scanning Electron Microscopy/Energy Dispersive X-Ray (SEM/EDX) analysis.

An additional study was performed to get a clear picture of the beneficial effects of the pre-oxidation layer in relation to its location. To examine this question the samples were pre-oxidized and subsequently the resulting oxide layer was removed from one side of the sample via mechanical polishing. The samples were then exposed with the pre-oxidized surface either facing the fuel side or facing the air side. The exposure was interrupted after the same intervals as in the aforementioned experiment to visualize the progress of breakaway oxidation. Also these samples were analyzed using photographs and SEM/EDX analysis.
Cycling Performance of Vanadium Redox Flow Battery Using Anion Exchange Membrane Based on Im-bPPO
Authors: Lim Min-Hwa , Jung Ho-Young
Published: February 2020

In this work, imidazole group containing brominated poly(phenylene oxide) (Im-bPPO), in which imidazole functional groups are introduced to brominated poly(phenylene oxide), are synthesized and used as a low-cost, hydrocarbon-based anion exchange membrane for vanadium redox flow battery (VRFB). Although the imidazole group containing brominated poly(phenylene oxide) (Im-bPPO) membrane has a room temperature ionic conductivity of 0.02 S cm-1, which is somewhat lower than that of Nafion 212 (0.08 S cm-1), it shows three orders of magnitude lower VO2+ permeability of 1.75×10-9 cm2 min-1 compared with Nafion 212 (1.41×10-6 cm2 min-1), suggesting its benefit of easier rebalancing control during VRFB operation. In comparison with the single cells using Nafion 212, the Im-bPPO membrane-based cell has a higher coulombic efficiency (CE) because of its excellent rejection of vanadium ions. However, the voltage efficiency (VE) of the Im-bPPO-based cell is lower than that of Nafion 212-based cell due to the lower ionic conductivity of the Im-bPPO membrane. Also, the cycle life of the Im-bPPO-based cell is 15 times shorter than the Nafion 212-based cell because of the chemical deterioration by highly oxidative VO2
+ ions as observed for other hydrocarbon-based membranes. These results demonstrate the advantage of hydrocarbon-based anion exchange membrane in preventing vanadium crossover, but present a challenge in improving chemical stability for practical usage.

Keywords: Vanadium Redox Flow Battery; Anion Exchange Membrane; Imidazole; Polyphenylene Oxide (PPO)

Figure 1
Growth of V2O5 Films for Electrochromic and Battery Applications by Pulsed Chemical Vapour Deposition
Authors: Kazadojev Igor I , O'Brien S , Ryan Louise P , Modreanu M , Osiceanu P , Somacescu S , Vernardou D , Pemble Martyn E , Povey Ian M
Published: February 2020

Pulse chemical vapour deposition (CVD), or more correctly atomic layer deposition (ALD) outside of the ALD thermal window, was used to grow vanadium pentoxide films using Tetrakis(dimethylamino)vanadium (IV) (V(NMe2)4) as the vanadium source and either oxygen-argon plasma, oxygen or water as the co-reagent. Growths were performed at 150-300°C for 400 cycles, resulting in a range of both stoichiometric and non-stoichiometric vanadium oxides. Post growth annealing in air at 400°C for both thermal and plasma assisted methods resulted in the formation of orthorhombic α – V2O5. Electrochemical characterization revealed that the samples grown at 250°C using a plasma process and a post growth anneal demonstrate the best electrochemical properties in terms of current density and charge density with values of 0.35 mAcm-2and 55 mCcm-2 respectively. In addition, the samples grown under these conditions also possess the best electrochromic response, exhibiting a change in percentage transmission between the bleached and coloured states of 65%. The influence of growth parameters on material properties is discussed.
Numerical Investigation of Thermal Management for Lithium-Ion Battery Pack Under Thermal Abuse Condition
Authors: Li Qibo , Yang Chuanbo , Santhanagopalan Shriram , Lamb Joshua , Steele Leigh Anna M , Torres-Castro Loraine
Published: February 2020

Abstract

Thermal runaway and its propagation is a big concern for the application of lithium-ion battery. [1] In order to control the propagation in a battery pack, different types of passive cooling have been used as the heat sink of lithium-ion battery packs, such as phase change materials [2] or metal plates. [3] Aluminum has been used widely as it is a relatively light and common material with high thermal conductivity and specific heat. However, how to optimize the configuration of aluminum heat sinks to prevent thermal runaway propagation is still unclear. Recently, Sandia National laboratories [4] assembled modules with aluminum plates of different thicknesses between pouch cells, and investigated experimentally the effect of plate thickness on thermal runaway propagation in a battery module. In the present study, NREL co-investigated these results from Sandia National Laboratories using numerical simulations. [5] This talk addresses the mechanism of thermal runaway propagation in detail. The dominant parameters to prevent propagation are identified. Moreover, an optimum configuration for the aluminum heat sink is proposed. The study provides further insights into the optimization of aluminum heat sink design for lithium-ion battery packs.

Acknowledgement

This study was supported by Computer Aided Engineering for Batteries (CAEBAT) project of the Vehicle Technologies Office, Office of Energy Efficiency and Renewable Energy, U.S. Department of Energy. The research was performed using computational resources sponsored by the Department of Energy's Office of Energy Efficiency and Renewable Energy, located at the National Renewable Energy Laboratory.

Reference

[1] T. Reddy, Linden’s Handbook of Batteries, McGraw-Hill Professional (2010).

[2] S.A. Khateeb, M.M. Farid, J.R. Selman, and S. Al-Hallaj, Design and simulation of a lithium-ion battery with a phase change material thermal management system for an electric scooter, Journal of Power Sources. Vol. 128(2), pp: 292-307 (2004)

[3] E. Darcy, Passively Thermal Runaway Propagation Resistant Battery Module that Achieves > 190 Wh/kg, Sustainable Aircraft Symposium. Retrieved from https://ntrs.nasa.gov/search.jsp?R=20160003490 2017-11-16T22:50:41+00:00Z

[4] J. Lamb, C.J. Orendorff, L.M. Steele, S.W. Spangler, Failure propagation in multi-cell lithium ion batteries, Journal of Power Sources, Vol. 283, PP:517-235, (2015)

[5] G. H. Kim, K. Smith, K. J. Lee, S. Santhanagopalan, and A. Pesaran, Multi-domain modeling of lithium-ion batteries encompassing multi-physics in varied length scales, J Electrochem Soc, 158(8), pp: 955-969 (2011).

Figure 1
Analysis of Temperature Gradients in Lithium-Ion Batteries By Electrothermal Impedance Spectroscopy (ETIS)
Authors: Dippon Michael , Weber André , Ivers-Tiffée Ellen
Published: February 2020

While the surface temperature (Tsurf) of a lithium-ion cell is measurable by an external temperature sensor, the internal temperature (Tint) remains unknown. The difference between the surface temperature and the internal temperature increases with charging/discharging rate and with cell volume. A thermal model describing the correlation between load and cell temperature is necessitated, and requires reliable parameter settings.

The electrothermal impedance spectroscopy (ETIS) is an in-situ method, which determines the thermal impedance and parameterizes a thermal model. ETIS is comparable with electrochemical impedance spectroscopy (EIS), but in ETIS the excitation signal is a sinusoidal heat flow q(t), which leads to a sinusoidal temperature response (Tint(t) and Tsurf(t)). From the input signal q(t) and output signal T(t) the thermal impedance can be calculated. Using a simple thermal model (Figure 1 b)) and the measured thermal impedance (Figure 1 a)), the temperature change and the difference between the internal temperature and the surface temperature can be calculated as a function of the load current.

Consequently, the ETIS-Method was applied to a high energy (KOKAM 560 mAh) and to a high power (KOKAM 350 mAh) lithium-ion pouch cell. Both are made of a NCA-LCO blend cathode and a graphite anode, but differ in electrode thickness.

The study shows that the simple model from Figure 1 b) sufficiently describes the thermal behavior of both commercial cell types. The parametrized model describes fairly well the thermal gradient from Tsurf to Tint and is capable to quantify the thermal gradients in lithium-ion cells. The thermal resistance Rth of the high energy pouch cell is more than doubled (2.5 K/W) comparing to the high power cell (1 K/W), thus reflecting the influence of electrode thickness to the thermal behavior of a lithium-ion cell.

Figure 1
In Situ Investigation of Morphological Changes in Discharging Alkaline Zinc-Manganese Dioxide Batteries By Transmission X-Ray Microscopy
Authors: Raj Abhi , Kim Andrew , Park Jeung Hun , Steingart Daniel A
Published: February 2020

Alkaline Zn-MnO2 batteries are one of the most widely used battery chemistries. Significant research has been made to investigate the chemical processes in these batteries in an effort to prolong lifetime under high discharge rates. One promising candidate for this characterization is X-ray transmission microscopy (TXM), a technique which offers the ability to probe the internal structures of the battery, without dismantling the cell. In this work, we use an in-house TXM to take snapshots of commercially available AA alkaline Zn-MnO2 cells at a series of discharge rates and temperature conditions. As the cells discharge, morphological changes are tracked as MnO2 is reduced and Zn is converted to ZnO.
Designing a High-Performance Core-Shell Nanorod-Based WO3 // WO3/MnO2 Hybrid Ultracapacitor: A Structure and Property Correlation Study
Authors: Sarkar Debasish , Mukherjee Soham , Das Sarma Dipankar , Shukla Ashok Kumar
Published: February 2020

Densely-packed nanorods (NRs) of highly-crystalline hexagonal WO3 (h-WO3) are grown on carbon cloth substrate using a hydrothermal method. XRD data reveal that the structure comprises an open framework of interconnected WO6 octahedra with numerous cavities running across the NR length. These tunnels facilitate fast intercalation/deintercalation of protons during electrochemical reactions in conjunction with the surface-based redox processes, thereby contributing significantly towards high-charge storage capacity of WO3 anode. On the positive electrode, these NRs have been utilized as scaffold to deposit nano-flakes of MnO2, thus forming WO3/MnO2 core/shell NRs. The cathode shows attractive capacitance value of 2361 mF/cm2 which is higher than the value for pristine MnO2 nano-flakes at a current density of 1 mA/cm2 and is facilitated by the high surface area owing to the core-shell NR design together with mixed protonic-electronic conductivity of WO3 NRs. The assembled WO3//WO3/MnO2 hybrid asymmetric supercapacitor exhibits volumetric capacitance of 7.22 F/cm3 together with maximum energy and power density values of 3.25 mWh/cm3 and 411 mW/cm3, respectively, within a potential window of 1.8 V. Accordingly, the study demonstrates the versatility of h-WO3 in designing both the negative and positive electrodes for hybrid ultracapacitors.
Physical Interpretations of Impedance Spectra for Pseudocapacitive Electrodes
Authors: Mei Bing-Ang , Pilon Laurent
Published: February 2020

Electrochemical impedance spectroscopy (EIS) has been used widely to determine the properties of pseudocapacitive electrodes. It consists of applying a low-amplitude sinusoidal voltage to a steady-state potential and measuring the output sinusoidal current. Using complex notations, the impedance of the electrodes can be determined by dividing the oscillating potential by the oscillating current. The impedance spectra, including the Nyquist plots and Bode plots, are informative to determine the properties of the electrodes. However, the interpretation of impedance spectra has been a “subject of controversy”.

This study aims to provide physical insights in interpreting the impedance spectra of pseudocapacitive electrodes by numerically reproducing EIS measurements in a three-electrode setup. The continuum model used was based on the modified Poisson-Nernst-Planck model combined with the Butler-Volmer equation and accounted for (i) charge transport in both electrodes and electrolyte, (ii) the dynamics of the electric double layer, (iii) steric repulsion due to finite ion sizes, (iv) reversible redox reactions, and (v) intercalation. The effect of the electrode and electrolyte resistance, charge transfer resistance at the electrode/electrolyte interface were separated numerically by varying the bulk ion concentration, electrolyte length, redox reaction rate constant, and the steady-state potential, i.e., the biased potential. Moreover, the faradaic and capacitive contributions of the impedance can be interpreted separately. Therefore, the behaviour in each frequency regime in the impedance spectra can be related to specific physical processes.
Mathematical Modeling of the Li2s Precipitation Process in Li-S Batteries
Authors: Xie Yuanyuan , Srinivasan Venkat
Published: February 2020

The lithium sulfur battery is a promising energy storage device due to its high theoretical energy density and the abundancy of sulfur deposits. One of the key issues that limits this chemistry is the precipitation of Li2S in the discharge process. Because of its low solubility in the electrolyte solution, Li2S deposition on the surface impedes the reaction by increasing the impedance at the interface. In this study, we will describe a mathematical model, based on the phase field approach, to track the precipitation of Li2S during the discharge process. The phase field model is employed because of the ease of modeling the interfacial region, by employing continuous order parameters between two adjacent phases to avoid tracking the sharp interface. The influence of different operating parameters will be explored to reveal the mechanisms behind the precipitation process.
Oxygen Reduction Reaction of Perovskite Electrocatalysts in Alkaline Media at a Rotating Disk Electrode: Mechanism Analysis
Authors: Jin Xinfang , Mattick Viki , Huang Kevin
Published: February 2020

Owing to their high theoretical specific energy density offered by the metal-oxygen chemistry, rechargeable metal-air batteries have garnered much attention in recent years. The major technical challenge of the batteries lies in developing novel low-cost and durable bifunctional oxygen electrocatalysts. In search of such materials, Linear sweep voltammetry (LSV) and Electrochemical Impedance Spectroscopy (EIS) are conventional techniques used to characterize their catalytic activity. However, due to the complicated multi-step and parallel reactions occurring simultaneously at the oxygen electrode, the classical methods of data analysis are not applicable, such as Levich Equation, Equivalent Circuit method. In this paper, we proposed a physics-based model to include multiple oxygen transfer pathways and further estimate parameters from experimental data of Lanthanum Cobalt Oxide (LCO) catalyst at a rotating disk electrode (RDE). The model is capable to predict reaction kinetics of both sequential two-step oxygen reduction mechanism and direct one-step four-electron transfer mechanism, as well as peroxide disproportion reaction. Nonlinear parameter estimation technique is applied to obtain the relevant kinetic and transport parameters. The modeling results will give experimentalists a guideline in understanding the ORR mechanism for LCO catalyst.
Single-Step Deposition of Nanostructured Fe2O3 as Anode for Li-Ion Batteries
Authors: Wang Yang , Roller Justin , Maric Radenka
Published: February 2020

Alpha phase iron oxide has been investigated as active anode material for lithium ion batteries because of high theoretical specific capacity, low cost and eco-friendly nature. Porous nanostructured electrode materials directly deposited on current collectors effectively enhance the rate performance of Li-ion batteries. The unique structure provides open channels for electrolyte penetration and short diffusion pathways for Li ions and electrons. In addition, the open spaces can accommodate the large volume change from the repeated conversion reaction of α-Fe2O3 during cycling.

A simple and economical manufacturing approach of the nanostructured electrodes is essential to the development and application of the next generation Li-ion batteries. In this study, nanostructured α-Fe2O3 electrodes are fabricated by reactive spray deposition technology (RSDT) which is a single-step flame combustion synthesis method. This process is continuous and scalable. The structure and morphology of as-prepared electrode are investigated by X-ray diffraction, scanning electron microscopy and transmission electron microscopy. Electrochemical properties of the nanostructured α-Fe2O3 electrodes are studied using cyclic voltammetry, galvanostatic charge/discharge cycling and electrochemical impedance spectroscopy in half-cell configuration.
Understanding the Dynamics of Primary Zn-MnO2 Alkaline Battery Gassing with Operando Visualization and Pressure Cells
Authors: Faegh Ehsan , Omasta Travis J , Hull Matt , Zuraw Michael , Mustain William E
Published: February 2020

The leading cause for safety vent rupture in alkaline cells is the intrinsic instability of zinc in the highly alkaline reacting environment. Zinc and aqueous KOH react in a parasitic process to generate hydrogen gas, which can rupture the seal and vent the hydrogen along with small amounts of electrolyte. The expelled electrolyte is known to cause damage to consumer electronics equipment, and also leads to brand damage. Under most circumstances, cells are engineered to slow the hydrogen evolution process, and its effects are never apparent to the end user. However, abusive conditions (i.e. over discharge) can accelerate the rate of gassing. Industry leaders have been cognizant of this for years, and improved techniques to understand and mitigate zinc corrosion have long been desired.

In order to understand the fundamental drivers and mechanisms for such gassing behavior, our team has developed a new research platform that enables a cross-sectional view of the cell during charge and discharge (Figure 1). There also exists version of the cell that can actively measure pressure as well as the potential distribution across the cell. In this study, several parameters were investigated and it was confirmed that the formation of high surface area (or so-called “black”) zinc during cell discharge was the root cause for accelerated gassing. Steep concentration gradients caused by the cell balance and chemistry are responsible for black zinc formation and subsequent hydrogen evolution. Also, it was confirmed that in deeply discharged cells, significant hydrogen evolution does not occur during discharge because of unfavorable electrochemical conditions; gassing occurs when the cell is off load. In this talk, the fundamental mechanisms and operational parameters controlling black zinc formation will be discussed. Also, possible pathways forward for action and further research will be proposed.

Figure 1
High Performance Composite Nanofibers-Based Piezoelectric Energy Harvesters
Authors: Kim Ji Won , Kim Da Bin , Choi Hong Je , Kim Seung Won , Jung Yeseul , Han Chan Su , Cho Yong Soo
Published: February 2020

This work demonstrates the best piezoelectric energy harvesting performance of highly flexible nanofiber-based composite nanogenerators with very promising charging capability. The exceptional selection of high piezoelectric coefficient Pb(Zn1/3Nb2/3)O3–Pb(Zr0.5Ti0.5)O3 (PZN-PZT) nanoparticles enables the nanogenerators to be very competitive. It covers the entire procedure of fabricating the energy harvesters, i.e., (i) finding optimal composition in the system of PZN-PZT, (ii) synthesising nanoparticles by combustion reaction, (iii) treating surface of the nanoparticles, (iv) producing nanoparticle-dispersed composite nanofibers, (v) fabricating nanogenerators, and (iv) suggesting the enhanced way of charging capability by designing electrical connections. The achieved harvesting performance of ~3.4 V and ~240 nA is the best one so far for the nanofiber-based piezoelectric energy harvesters. The promising result is possible by adopting the optimal composition of 0.4Pb(Zn1/3Nb2/3)O3–0.6Pb(Zr0.5Ti0.5)O3, which is far better than pure PZT in terms of piezoelectric properties. Composite nanofiber sheets consisting of uniformly distributed nanoparticles in the P(VDF-TrFE) polymer matrix are successfully demonstrated. The stacking approach of the composite sheets with a series connection suggests that the charging capability can be further enhanced depending on the number of stacking sheets. As an example, only double-layered sheets exhibit a ~5.7 V charging performance within ~150 seconds.
La, Rb and Ba Additions on the Effect of Oxygen Reduction in Molten Alkali Carbonates
Authors: Lee Choong-Gon
Published: February 2020

In this study, the effects of La, Rb and Ba additions to (Li+Na)CO3 electrolyte were investigated using a half-cell and a coin-type MCFC. The effect of La and Rb on oxygen reduction on a gold electrode in a (Li+Na)CO3 melt at 650oC were examined using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The C
0
D
0
0.5 values determined from CV and EIS were not comparable. The addition of 0.5 mol% of La2O3 to (Li + Na)CO3 showed a remarkable increase in C
0
D
0
0.5 values determined by both EIS and CV analyses. The effect of La and Rb on cell performance of coin cells using (Li+Na)CO3 as electrolyte and operated at 650oC were examined using I-V curve. The total overpotential was decreased by 13% when 0.5 mol% of La2O3 was added to (Li + Na)CO3 electrolyte but was decreased by 9% when 3 mol% of Rb2CO3 was added to (Li + Na)CO3.
(Nanocarbons Division SES Young Investigator Award Address) Bottom-up Synthesis of Semiconducting Graphene Nanoribbons via CVD
Authors: Arnold Michael S
Published: February 2020

We have discovered how to drive graphene crystal growth with a large shape anisotropy through control of kinetics on the surface of Ge(001) single crystal wafers via CH4 chemical vapor deposition. This discovery enables the direct synthesis of narrow, armchair, semiconducting nanoribbons. The ribbons are self-orienting, self-defining, and have smooth edges. The ribbons exhibit exceptional transport properties (e.g., high on-state conductance and on/off ratio at room temperature) and provide a promising pathway towards the direct integration of high-performance nanocarbon electronics onto conventional semiconductor wafer platforms.

This talk will detail the synthesis of these ribbons (including seeded arrays of ribbons), the elucidation of their structure, and the characterization of their promising charge transport properties.

M. Jacobberger, B. Kiraly, M. Fortin-Deschenes, P. L. Levesque, K. M. McElhinny, G. J. Brady, Richard Rojas Delgado, S. Singha Roy, A. Mannix, M. G. Lagally, P. G. Evans, P. Desjardins, R. Martel, M. C. Hersam, N. P. Guisinger, M. S. Arnold, Direct Oriented Growth of Armchair Graphene Nanoribbons on Germanium, NATURE COMMUNICATIONS, 6, 8006 (2015).

Kiraly, A. J. Mannix, R. M. Jacobberger, B. L. Fisher, M. S. Arnold, M. C. Hersam, N. P. Guisinger, Sub-5 nm, Globally Aligned Graphene Nanoribbons on Ge (001), APPLIED PHYSICS LETTERS, 108, 213101 (2016).

M. Jacobberger, M. S. Arnold, High Performance Charge Transport in Semiconducting Armchair Graphene Nanoribbons Grown Directly on Germanium. ACS NANO, 11, 8924 (2017).

J. Way, R. M. Jacobberger, M. S. Arnold, Seed-Initiated Anisotropic Growth of Unidirectional Armchair Graphene Nanoribbon Arrays on Germanium, SUBMITTED (2017).

S. Arnold, R. M. Jacobberger, Oriented Bottom-Up Growth of Armchair Graphene Nanoribbons on Germanium, U.S. PATENT 9,287,359 (2016).

S. Arnold, A. J. Way, R. M. Jacobberger, Seed-Mediated Growth of Patterned Graphene Nanoribbon Arrays, U.S. PATENT 9,761,669 (2017).