A high energy density all solid-state tungsten–air battery

White

Huang

2013

Self Cite

A rigorous physics-based mathematical model for a solid oxide iron-air redox flow battery system is presented in this paper. The modeled flow battery system combines a Fe-FeO redox couple as the energy storage unit and a regenerative solid oxide fuel cell as the electrical functioning unit in a 2D axial symmetric geometry. This model was developed from fundamental theories of reaction engineering in which basic transport phenomena and chemical/electrochemical kinetics are included. The model shows good agreement with the experimental data. Simulation results for the chemical, electrochemical and transport behavior of the battery are discussed.

Section: Mathematical Modelmentioning

confidence: 99%

mentioning

confidence: 99%

A Multi-Physics Model for Solid Oxide Iron-Air Redox Flow Battery: Simulation of Discharge Behavior at High Current Density

White

Huang

2013

Self Cite

“…Energy conservation.-Governing equations.-The energy conservation equation applied to air channel, RSOFC, OSG chamber and RCU including conduction, convection and diffusion can be expressed by, [19] where k T is the thermal conductivity of the gas mixture; ρ is the density of gas mixture; C p is the specific heat capacity of gas mixture. For the solid phase (RSOFC or RCU), the second term on the left side of the equation disappear.…”

Section: Source Termmentioning

confidence: 99%

“…The advantages of SOMARB include double electron transfer (O 2− ), energy storage in a chemical bed separated from the electrode, fast charging and discharging rate, use of earth-abundant element such as iron for energy storage, scalability and operational safety. Since its debut in 2011, 1 significant progress has been made in the areas of electrochemical performance optimization, [2][3][4][5][6][7][8][9][10][11][12] new metal-air chemistries [13][14][15][16][17][18][19][20] and multiphysics modeling of electrochemistry, mass transport and chemical redox kinetics that govern the electrical behaviors of the battery. [21][22][23] However, these studies were all performed isothermally with a focus on evaluating the factors that can affect the electrochemical performance of the battery.…”

mentioning

confidence: 99%

Heat Balance in a Planar Solid Oxide Iron-Air Redox Battery: A Computational Analysis

Jin

White

et al. 2015

Self Cite

In the present computational study, a thermal flow analysis is performed on a large-scale (10 × 10 cm) planar Solid Oxide Iron-Air Redox Battery (SOIARB) operated at 800 • C. The results explicitly indicate that the heat generated during the discharge cycle is more than what is needed for the charge cycle. Use of air as a working fluid to regulate the heat flow and heat balance within the battery is a practical engineering solution to maintain the desirable operating temperature and high energy efficiency for the battery system. Air utilization and inlet temperature are the two most important parameters that can be adjusted to regulate the heat flow between cycles. The analysis also shows that operating at a higher current density, around 1500 A/m 2 , the battery becomes thermally self-sustainable, but at the expense of lowered electrical cycle efficiency. For any type of reversible battery, the heat effect associated with the charge and discharge reactions are always opposite, viz. endothermic vs exothermic. When the operating temperature of a reversible battery is well above the ambient temperature, the magnitude of heat produced/absorbed and its subsequent impact on the distribution of local temperature within the battery (and stack) components can be significant. A proper management of the heat flow during the charge and discharge cycle will not only minimize the temperature gradient, thus thermal stresses, but also improve the overall energy efficiency of the battery system.The recently developed Solid-Oxide Metal-Air Redox Battery (SOMARB) is a type of high-temperature reversible battery. The advantages of SOMARB include double electron transfer (O 2− ), energy storage in a chemical bed separated from the electrode, fast charging and discharging rate, use of earth-abundant element such as iron for energy storage, scalability and operational safety. Since its debut in 2011, 1 significant progress has been made in the areas of electrochemical performance optimization, 2-12 new metal-air chemistries [13][14][15][16][17][18][19][20] and multiphysics modeling of electrochemistry, mass transport and chemical redox kinetics that govern the electrical behaviors of the battery. [21][22][23] However, these studies were all performed isothermally with a focus on evaluating the factors that can affect the electrochemical performance of the battery. The temperature nonuniformity caused by the opposite heat flows during the endothermic charge and exothermic discharge reactions has not yet been investigated in the past. The objective of the present study is to fill this gap by performing a computational analysis of heat flows and balance within components of a planar SOMARB subject to a typical charge and discharge cycle. With the basic thermal information in hand, a proper engineering design can be realized. Fig. 1 shows a perceived SOMARB system encompassing thermal storage and heat exchanger with air as the working fluid. Mathematical ModelThe cell structure of a SOMARB on which the mathematical model is built is show...

“…Since the first demonstration of oxide-ion-chemistry based anodesupported tubular Solid-Oxide Iron-Air Redox Battery (SOIARB) in 2011, 1 significant progress has been made experimentally in the areas of materials identification, [2][3][4][5] new metal-air chemistries 1,[6][7][8][9][10][11][12][13][14] and performance optimization. [15][16][17][18][19][20] In contrast, theoretical understanding of the operating oxygen shuttle mechanisms of the new battery lags behind.…”

mentioning

confidence: 99%

Understanding the High-Temperature Solid-Oxide Iron-Air Redox Battery Operated with an Oxygen Shuttle Mechanism: A Computational Study

Jin

Uddin

et al. 2015

Self Cite

In this computational study, we demonstrate the use of a high-fidelity multiphysics model to predict the effects of operational parameters and the performance of a new Solid Oxide Iron-Air Redox Battery (SOIARB) operated at 800 • C. The results show explicitly that the operating current density has the most pronounced effect on the H 2 concentration distribution, Nernst potential, specific energy and round-trip efficiency. The initial porosity in the Redox Cycle Unit (RCU) must be >0.50 at high current density in order to avoid significant diffusion limitation. Also, the distance between the RSOFC (reversible Solid Oxide Fuel Cell) and the RCU has little effect on the performance of the SOIARB, but has an appreciable effect on the chamber pressure. The simulations indicate that a high round-trip efficiency (RTE) can be achieved at the expense of useful capacity. Enhancement of the electrolysis electro-kinetics of RSOFC and FeO-reduction kinetics of RCU is a key to achieving high capacity with high efficiency. Since the first demonstration of oxide-ion-chemistry based anodesupported tubular Solid-Oxide Iron-Air Redox Battery (SOIARB) in 2011, 1 significant progress has been made experimentally in the areas of materials identification, 2-5 new metal-air chemistries 1,6-14 and performance optimization. [15][16][17][18][19][20] In contrast, theoretical understanding of the operating oxygen shuttle mechanisms of the new battery lags behind. In the open literature, only Ohmoti et al. 21,22 and Guo et al. 23 have reported multiphysics models for the battery. However, neither of them has considered the important time-dependent chemical redox kinetics taking place within the energy storage component, referred to as the Redox Cycle Unit or RCU. To address this problem, we have recently established a high-fidelity multiphysics model with parameters directly validated by experimental results and a chemical redox kinetics model based on Johnson-Mehl-Avrami-Kolmogorov (JMAK) and Shrinking Core theories. 24 Integrated with mass transport of H 2 -H 2 O, charge transfer in the Reversible Solid Oxide Fuel Cell (RSOFC) and chemical redox kinetics in the RCU, the new model has been used to simulate the performance of SOIARB at 550• C with Fe/Fe 3 O 4 as the RCU material and H 2 -H 2 O as the oxygen shuttle gas (OSG).In this study, we present a computational analysis of a Solid-oxide Iron-air Redox Battery or SOIARB operated at 800• C by utilizing the same model. At 800• C, the energy storage redox couple is Fe/FeO according to thermodynamics, which equilibrates with an OSG composition of H 2 /H 2 O = 0.65/0.35 and generates a Nernst potential of 0.97 V vs air. To retain the high fidelity, all the parameters used by this model are directly validated by the experimental data obtained from our lab. This study is primarily focused on investigating the effects of current density, porosity of RCU and distance between RSOFC and RCU on the performance of a SOIARB. Key operational parameters are subsequently identified for future engineerin...