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Novel magnetic flowable electrode for redox flow batteries: A polysulfide/iodide case study

Rahimi, M ; Sharif University of Technology | 2021

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  1. Type of Document: Article
  2. DOI: 10.1021/acs.iecr.0c05768
  3. Publisher: American Chemical Society , 2021
  4. Abstract:
  5. A novel approach named a magnetic flowable electrode (MFE) is proposed for the first time to enable enhancement of redox flow batteries (RFBs) performance. This approach enables the formation of a high active surface area electrode from magnetic nanomaterials, without the need to fabricate a self-supporting three-dimensional electrode structure. To form a simple MFE, magnetic modified carbon nanotubes are dispersed in the electrolyte, and permanent magnets are embedded behind the current feeder to apply a magnetic field across the flow cell channels. With circulating electrolyte, magnetic carbon nanotubes are aggregated on the graphite bipolar plate to form a well-structured nanoscale percolating network and chains serving as an electrode. The superior electrochemical activity and stability of the MFE approach is demonstrated successfully relative to a conventional stationary carbon felt electrode using the positive electrode of a polysulfide-iodide RFB. The MFE provides high electrochemical active surface area and porosity, which result in lower cell impedances and pump losses, and higher battery efficiencies. The polysulfide-iodide RFB using an MFE gives stable cycling performance over 200 cycles (with replacement of the electrolyte after 100 cycles) and delivers a high energy efficiency of 79.3% at a current density of 20 mA cm-2, which is larger than all previous reports for this RFB system. The MFE design opens new opportunities to develop the next-generation RFB systems and can be applied in various flow battery chemistries. © 2020 American Chemical Society
  6. Keywords:
  7. Carbon nanotubes ; Electrolytes ; Energy efficiency ; Flow batteries ; Magnetic materials ; Nanomagnetics ; Polysulfides ; Carbon felt electrodes ; Electrochemical active surface areas ; Electrochemical activities ; Graphite bipolar plates ; High energy efficiency ; Magnetic carbon nanotubes ; Magnetic nanomaterials ; Three-dimensional electrode ; Electrochemical electrodes
  8. Source: Industrial and Engineering Chemistry Research ; Volume 60, Issue 2 , 2021 , Pages 824-841 ; 08885885 (ISSN)
  9. URL: https://pubs.acs.org/doi/10.1021/acs.iecr.0c05768