Buckingham, Mark A.Mark A.BuckinghamLaws, KristineKristineLawsLi, HuanxinHuanxinLiKuang, YafeiYafeiKuangLEIGH ALDOUS2024-09-182024-09-182021https://www.scopus.com/record/display.uri?eid=2-s2.0-85115998922&origin=resultslisthttps://scholars.lib.ntu.edu.tw/handle/123456789/721010論文編號: 2002539The 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 Authorselectrochemistryenergy harvestingredox-active electrolytessustainable energythermocellthermoelectrochemistrythermogalvanicwater-in-salt electrolytejournal article10.1016/j.xcrp.2021.1005102-s2.0-85115998922