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Hawthorne Dissertation 2014.pdf (3.17 MB)

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Iron-Ligand Electrokinetics towards an all-Iron Hybrid Redox Flow Battery

Hawthorne, Krista Leigh
http://rave.ohiolink.edu/etdc/view?acc_num=case1405002859

Abstract Details

2014, Doctor of Philosophy, Case Western Reserve University, Chemical Engineering.
Flow batteries as a large scale energy storage technology have seen a renewed interest in recent years with the implementation of renewable energy sources on the grid. One such flow battery is the all-iron chemistry. The all-iron flow battery utilizes the Fe II/III redox couple as the positive electrode and the Fe II/0 reaction as the negative electrode. Iron plating in the negative electrode occurs in the cell stack, necessitating intelligent design of the porous electrode structure to maximize plating density, and thus energy storage density. Due to the negative potential of the iron plating reaction, hydrogen evolution is a main concern in long term operation of the all-iron flow battery. As hydrogen evolves the electrolyte pH will rise, causing precipitation of the ferric ions in the positive electrolyte. This research addresses three critical aspects of the chemistry and design of the all-iron flow battery. First, to increase the ferric ion solubility in relatively high pHs (pH 2 – 3), complexing ligands are considered as an electrolyte additive. Kinetic and mass transfer behavior of several iron-ligand complexes are examined. An electrolyte containing a 0.5:1 glycine to iron ratio showed Fe3+ solubility at pHs greater than 2.5 and reasonable kinetic performance on a glassy carbon electrode. Modeling of the equilibrium species in an iron-glycine solution is used to design an electrolyte with the desired solubility and concentration of Fe3+. Second, the iron deposition reaction is considered in conjunction with added ligand. Further suppression of hydrogen evolution was also considered through the use of various supporting electrolytes. High concentrations of chloride ions were found to hinder hydrogen evolution in the negative electrolyte, both on an iron rod electrode and in an all-iron flow battery. Third, the plating capacity of the negative deposition electrode is considered. Six three dimensional electrode structures are presented, and an achievable plating density of 150 mAh/cm2 is demonstrated in two separate electrode structures. Cycling of an all-iron flow battery with a voltaic efficiency of 80% is demonstrated.
Robert Savinell (Advisor)
Jesse Wainright (Advisor)
177 p.
Chemical Engineering; Energy
Flow Battery; Hybrid Flow Battery; Energy Storage

Recommended Citations

Citations

  • Hawthorne, K. L. (2014). Iron-Ligand Electrokinetics towards an all-Iron Hybrid Redox Flow Battery [Doctoral dissertation, Case Western Reserve University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=case1405002859

    APA Style (7th edition)

  • Hawthorne, Krista. Iron-Ligand Electrokinetics towards an all-Iron Hybrid Redox Flow Battery. 2014. Case Western Reserve University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=case1405002859.

    MLA Style (8th edition)

  • Hawthorne, Krista. "Iron-Ligand Electrokinetics towards an all-Iron Hybrid Redox Flow Battery." Doctoral dissertation, Case Western Reserve University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=case1405002859

    Chicago Manual of Style (17th edition)

case1405002859
3,656
© 2014, some rights reserved.Creative Commons License Iron-Ligand Electrokinetics towards an all-Iron Hybrid Redox Flow Battery by Krista Leigh Hawthorne 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