Thermogalvanic cells demonstrate inherent physiochemical limitations in redox-active electrolytes at water-in-salt concentrations
Journal
Cell Reports Physical Science
Journal Volume
2
Journal Issue
8
Start Page
2002539
ISSN
26663864
Date Issued
2021
Author(s)
Abstract
The majority of usable energy generated by humanity is lost as waste heat, but thermogalvanic systems (or thermocells) can address this problem by converting low-grade waste heat directly into electricity using redox chemistry. The concentration of the redox couple is a critical parameter; almost invariably, higher concentrations result in more power. This study exploits the simple synergy between Na+ and K+ counter ions to achieve—to the best of our knowledge—the most concentrated stable aqueous ferricyanide/ferrocyanide thermocell to date, at 1.6 m [Fe(CN)6]3−/4−. Despite increasing the concentration by 400% relative to the standard K3/K4[Fe(CN)6] electrolyte (0.4 m), electrical power production increased only 166%. Pushing the system from conventional salt-in-water electrolytes into the quasi-stable water-in-salt region (up to 2.4 m) resulted in a decrease in power. Detailed characterization highlighted the various physicochemical hurdles introduced by these extremely concentrated electrolytes; the identified issues have direct relevance to other energy systems also seeking to use the highest possible concentration. © 2021 The Authors
Subjects
electrochemistry
energy harvesting
redox-active electrolytes
sustainable energy
thermocell
thermoelectrochemistry
thermogalvanic
water-in-salt electrolyte
Publisher
Cell Press
Description
論文編號: 2002539
Type
journal article