title: Suspension Electrodes Combining Slurries and Upflow Fluidized Beds.
abstract: Carbon-based suspension electrodes are currently intensively investigated for emerging electrochemical systems, such as flow batteries, flow capacitors, and capacitive deionization cells. The main limitation of such electrodes is their low electric conductivity, which is typically orders of magnitude lower than that of traditional static carbon electrodes. Two main categories of suspension electrodes exist: 1) slurry electrodes where particles are not significantly affected by gravity, and 2) fluidized bed electrodes where particles are affected by gravity. We introduce a novel category that we term "combined" suspension electrodes, which combine dilute slurries and dense fluidized beds. We present experimental measurements of the electrochemical impedance and electric conductivity of two combined electrodes. For one set of materials, the measured electric conductivity of the combined electrode is at least an order of magnitude above the fluidized bed and slurry components alone, demonstrating that a synergetic effect can be achieved when adding dilute slurry to dense fluidized bed. For a second set of materials, results show that the combined electrode conductivity is lower than the slurry component alone, a counter-intuitive result, demonstrating that increasing electrode carbon loading does not always enhance the electric conductivity.
authors.affiliation: Faculty of Mechanical Engineering, Technion-Israel Institute of Technology, Haifa, Israel.
authors.forename: Hagai
authors.initials: H
authors.lastname: Cohen
authors.affiliation: Department of Physics, Technion-Israel Institute of Technology, Haifa, Israel.
authors.forename: Shaked Ein
authors.initials: SE
authors.lastname: Eli
authors.affiliation: Faculty of Mechanical Engineering, Technion-Israel Institute of Technology, Haifa, Israel.
authors.forename: Morten
authors.initials: M
authors.lastname: Jõgi
authors.affiliation: Faculty of Mechanical Engineering, Technion-Israel Institute of Technology, Haifa, Israel.
authors.forename: Matthew E
authors.initials: ME
authors.lastname: Suss
mesh_terms: D004553:Electric Conductivity; D017097:Electric Impedance; D055664:Electrochemical Techniques; D004566:Electrodes; D013535:Suspensions / Q000737:chemistry*
chemical_list: D013535:Suspensions
keywords: capacitive deionization; flow batteries; fluidized beds; slurries; suspension electrodes