Realization of an Asymmetric Non‐Aqueous Redox Flow Battery through Molecular Design to Minimize Active Species Crossover and Decomposition. Issue 24 (15th April 2020)

• Record Type: Journal Article
• Authors: Shrestha, Anuska; Hendriks, Koen H.; Sigman, Mathew S.; Minteer, Shelley D.; Sanford, Melanie S.
• Is Part Of: Chemistry. Volume 26:Issue 24(2020)
• Page Start: 5369
• Page End: 5373
• Publication Date: 2020-04-15
• Subjects: anolyte decomposition -- asymmetric -- crossover -- non-aqueous -- redox flow batteries; Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.202000749
• Languages: English
• ISSNs: 0947-6539

Abstract

Abstract: This communication presents a mechanism‐based approach to identify organic electrolytes for non‐aqueous redox flow batteries (RFBs). Symmetrical flow cell cycling of a pyridinium anolyte and a cyclopropenium catholyte resulted in extensive capacity fade due to competing decomposition of the pyridinium species. Characterization of this decomposition pathway enabled the rational design of next‐generation anolyte/catholyte pairs with dramatically enhanced cycling performance. Three factors were identified as critical for slowing capacity fade: (1) separating the anolyte–catholyte in an asymmetric flow cell using an anion exchange membrane (AEM); (2) moving from monomeric to oligomeric electrolytes to limit crossover through the AEM; and (3) removing the basic carbonyl moiety from the anolyte to slow the protonation‐induced decomposition pathway. Ultimately, these modifications led to a novel anolyte–catholyte pair that can be cycled in an AEM‐separated asymmetric RFB for 96 h with >95 % capacity retention at an open circuit voltage of 1.57 V. Abstract : Applied molecular design ! This study presents a mechanism‐based approach to the molecular design of electrolytes for implementation in an asymmetric non‐aqueous redox flow battery.