Stable, Impermeable Hexacyanoferrate Anolyte for Nonaqueous Redox Flow Batteries
- Argonne National Laboratory (ANL), Argonne, IL (United States); Indiana Univ.-Purdue Univ. Indianapolis (IUPUI), Indianapolis, IN (United States)
- Argonne National Laboratory (ANL), Argonne, IL (United States)
- Indiana Univ.-Purdue Univ. Indianapolis (IUPUI), Indianapolis, IN (United States); Purdue Univ., West Lafayette, IN (United States)
- Argonne National Laboratory (ANL), Argonne, IL (United States); Univ. of Illinois at Urbana-Champaign, IL (United States); Consejo Superior de Investigaciones Cientificas (CSIC), Madrid (Spain). Inst. de Ciencia de Materiales de Madrid, Cantoblanco
- Argonne National Laboratory (ANL), Argonne, IL (United States); Indiana Univ.-Purdue Univ. Indianapolis (IUPUI), Indianapolis, IN (United States); Purdue Univ., West Lafayette, IN (United States)
- Northern Illinois Univ., DeKalb, IL (United States)
- Argonne National Laboratory (ANL), Argonne, IL (United States); Northern Illinois Univ., DeKalb, IL (United States)
- Argonne National Laboratory (ANL), Argonne, IL (United States); Univ. of Illinois at Urbana-Champaign, IL (United States)
- Indiana Univ.-Purdue Univ. Indianapolis (IUPUI), Indianapolis, IN (United States)
Redox-active molecules, or redoxmers, in nonaqueous redox flow batteries often suffer from membrane crossover and low electrochemical stability. Transforming inorganic polyionic redoxmers established for aqueous batteries into nonaqueous candidates is an attractive strategy to address these challenges. Here, in this study, we demonstrate such tailoring for hexacyanoferrate (HCF) by pairing the anions with tetra-n-butylammonium cation (TBA+). TBA3HCF has good solubility in acetonitrile and >1 V lower redox potential vs the aqueous counterpart; thus, the familiar aqueous catholyte becomes a new nonaqueous anolyte. The lowering of redox potential correlates with replacement of water by acetonitrile in the solvation shell of HCF, which can be traced to H-bond formation between water and cyanide ligands. Symmetric flow cells indicate exceptional stability of HCF polyanions in nonaqueous electrolytes and Nafion membranes completely block HCF crossover in full cells. Ion pairing of metal complexes with organic counterions can be effective for developing promising redoxmers for nonaqueous flow batteries.
- Research Organization:
- Argonne National Laboratory (ANL), Argonne, IL (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES). Joint Center for Energy Storage Research (JCESR); USDOE Laboratory Directed Research and Development (LDRD) Program; USDOE Office of Science (SC), Basic Energy Sciences (BES). Scientific User Facilities (SUF); National Science Foundation (NSF)
- Grant/Contract Number:
- AC02-06CH11357
- OSTI ID:
- 2475772
- Journal Information:
- ACS Energy Letters, Journal Name: ACS Energy Letters Journal Issue: 9 Vol. 9; ISSN 2380-8195
- Publisher:
- American Chemical Society (ACS)Copyright Statement
- Country of Publication:
- United States
- Language:
- English