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Modeling and Simulation of Zinc-Bromine Redox Flow Batteries

Gol Ahmadi Avilagh, Bahram | 2022

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 55059 (06)
  4. University: Sharif University of Technology
  5. Department: Chemical and Petroleum Engineering
  6. Advisor(s): Molaei Dehkordi, Asghar
  7. Abstract:
  8. Zinc-bromine redox flow batteries are promising for large-scale energy storage applications due to their high energy density and open-circuit voltage. Proposed models for predicting these batteries' performance are limited due to challenges such as zinc deposition during the charging step and the utilization of a complexing agent. In this study, a 2D dynamic model was developed to investigate the battery performance. The kinetic equations for half-reactions are considered according to their two-step electron transfer mechanism. The model predictions were validated against experimental data reported in the literature for different current densities. Afterward, effects of various operating conditions such as electrolyte flow rate, electrodes compression ratio, thickness of separator, and the electrolyte concentration on battery performance were examined. Besides, due to the zinc deposition on the negative half-cell, parameters affecting the reaction distribution in a porous electrode were investigated in detail. The obtained results indicate that the reaction rate near the separator is larger than other parts of the electrode due to the high conductivity of the electrode relative to the electrolyte. On the negative compartment, only 24% of the electrode experiences zinc deposition due to the facile kinetics of the reaction; On the other hand, the positive half-reaction takes place all over the electrode. Decreasing electrolyte concentration increases the battery's internal resistance as well as zinc deposition near the separator; This also reduces the amount of deposited zinc near the current collector. Increasing the electrodes compression ratio up to 40% improves the battery performance due to the enhancement of electrode conductivity that also enhances the zinc deposition near the separator. Overall, accurate knowledge of the parameters affecting the distribution of reaction in a porous electrode can play an essential role in the optimal design of zinc-bromine redox flow batteries to improve the battery performance and minimize the possibility of separator damage or blockage of electrolyte pathway by zinc deposition
  9. Keywords:
  10. Energy Storage ; Modeling ; Simulation ; Electrochemical Reaction Distribution ; Hybrid Flow Battery ; Zinc-Bromine Flow Battery ;

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