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Fundamental Studies on Transport Phenomena in Redox Flow Batteries with Flow Field Structures and Slurry or Semi-Solid Electrodes: Modeling and Experimental Approaches

Ke, Xinyou
http://rave.ohiolink.edu/etdc/view?acc_num=case1543883710323558

Abstract Details

2019, Doctor of Philosophy, Case Western Reserve University, EMC - Mechanical Engineering.
Redox flow batteries with flow field designs have been demonstrated to boost their capacities to deliver high current density in medium and large-scale energy storage applications. Nevertheless, the fundamental mechanisms involved with improved current density in flow batteries with serpentine flow field designs have been not fully understood. In this dissertation work, one-dimensional (1D) analytical model, two-dimensional (2D) numerical model with scaling analysis, and three-dimensional (3D) model of a serpentine flow field over the porous carbon paper electrodes have been developed to examine the distributions and amounts of pressure driven electrolyte flow penetrations into the porous carbon paper electrodes. It was found that the electrolyte flow penetrations are strongly under-estimated by 1D analytical model and 2D numerical model. The scaling analysis also demonstrates that the flow penetrations enhanced by the adjacent flow channels are significant, and were not able to be incorporated in the 1D and 2D models. The 3D model accounts the effects of landings/ribs bridged between the adjacent flow channels on flow penetrations and better calculates the amount of flow penetrations into the porous carbon paper electrodes. It was also found that the flow penetrations are sensitive to the properties of the porous electrode, i.e. permeability and porosity, a smaller permeability or porosity results in a much smaller flow penetration. The model is used to estimate the maximum current densities associated with the stoichiometric availability of electrolyte reactant flow penetrations through the porous carbon paper electrodes. The modeling results match reasonably well observed experimental data without using any adjustable parameters. This fundamental work on electrolyte flow distributions of limiting reactant availability will contribute to a better understanding of limits on electrochemical performance in flow batteries with serpentine flow field designs and should be helpful to optimize flow batteries. Slurry or semi-solid electrodes are being developed for electrochemical flow capacitors and flow batteries to decouple power and energy. The utilization of slurry electrodes is a critical issue. The electronic conductivity of slurry electrodes is considered the most significant factor to determine the utilization of slurry electrodes and consequently affect the electrochemical performance. However, understanding fundamentals related to the electronic conductivity of slurry electrodes is quite limited and especially from the aspect of theory. The existing theories, i.e. effective medium theory and percolation theory, are inadequate for predicting electronic conductivity. These two theories do not consider the particle aggregations from the aspect of particle-to-particle interactions. Thus, an understanding of particle aggregations based on particle dynamics for understanding electronic conductivity is desired. By making force scaling analysis, it was found that the Brownian, Van der Waals attractive, electrostatic repulsive and electric forces are dominant in the particle dynamics of nano-scale particles. While, for the micro-scale particles, viscous, inertia, gravitational, buoyant and electric forces are dominant. It was also preliminarily found that the particle aggregations may be related to the conduction paths and consequently affect the electronic conductivity. Also, a novel design was developed to examine the electronic conductivity. Future work should focus on correlating the particle interactions for inducing conduction paths with the electronic conductivities of slurry or semi-solid electrodes.
Robert Savinell (Advisor)
Joseph Prahl (Advisor)
Jesse Wainright (Advisor)
Paul Barnhart (Committee Chair)
Sunniva Collins (Committee Member)
James T'ien (Committee Member)
246 p.
Applied Mathematics; Chemical Engineering; Energy; Fluid Dynamics; Mechanical Engineering; Physics
Redox flow batteries; electrochemical flow capacitors; flow field designs; slurry or semi-solid electrodes; limiting and maximum current densities; electronic conductivity; mathematical modeling; experimental design; cell performance optimization

Recommended Citations

Citations

  • Ke, X. (2019). Fundamental Studies on Transport Phenomena in Redox Flow Batteries with Flow Field Structures and Slurry or Semi-Solid Electrodes: Modeling and Experimental Approaches [Doctoral dissertation, Case Western Reserve University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=case1543883710323558

    APA Style (7th edition)

  • Ke, Xinyou. Fundamental Studies on Transport Phenomena in Redox Flow Batteries with Flow Field Structures and Slurry or Semi-Solid Electrodes: Modeling and Experimental Approaches. 2019. Case Western Reserve University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=case1543883710323558.

    MLA Style (8th edition)

  • Ke, Xinyou. "Fundamental Studies on Transport Phenomena in Redox Flow Batteries with Flow Field Structures and Slurry or Semi-Solid Electrodes: Modeling and Experimental Approaches." Doctoral dissertation, Case Western Reserve University, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=case1543883710323558

    Chicago Manual of Style (17th edition)

case1543883710323558
558
© 2019, some rights reserved.Creative Commons License Fundamental Studies on Transport Phenomena in Redox Flow Batteries with Flow Field Structures and Slurry or Semi-Solid Electrodes: Modeling and Experimental Approaches by Xinyou Ke is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License. Based on a work at etd.ohiolink.edu.
This open access ETD is published by Case Western Reserve University School of Graduate Studies and OhioLINK.
Release 3.2.12