MetILs3: A Strategy for High Density Energy Storage Using Redox-Active Ionic Liquids
A systematic approach is presented for increasing the concentration of redox‐active species in electrolytes for nonaqueous redox flow batteries (RFBs). Starting with an ionic liquid consisting of a metal coordination cation (MetIL), ferrocene‐containing ligands and iodide anions are substituted incrementally into the structure. While chemical structures can be drawn for molecules with 10 m redox‐active electrons (RAE), practical limitations such as melting point and phase stability constrain the structures to 4.2 m RAE, a 2.3× improvement over the original MetIL. Dubbed “MetILs 3 ,” these ionic liquids possess redox activity in the cation core, ligands, and anions. Throughout all compositions, infrared spectroscopy shows the ethanolamine‐based ligands primarily coordinate to the Fe 2+ core via hydroxyl groups. Calorimetry conveys a profound change in thermophysical properties, not only in melting temperature but also in suppression of a cold crystallization only observed in the original MetIL. Square wave voltammetry reveals redox processes characteristic of each molecular location. Testing a laboratory‐scale RFB demonstrates Coulombic efficiencies >95% and increased voltage efficiencies due to more facile redox kinetics, effectively increasing capacity 4×. Application of this strategy to other chemistries, optimizing melting point and conductivity, can yield >10 m RAE, making nonaqueous RFB a viable technology for grid scale storage.
- Research Organization:
- Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
- Sponsoring Organization:
- USDOE National Nuclear Security Administration (NNSA); USDOE Office of Electricity (OE)
- Grant/Contract Number:
- AC04-94AL85000; NA0003525
- OSTI ID:
- 1398783
- Alternate ID(s):
- OSTI ID: 1378388
- Report Number(s):
- SAND-2017-10038J; 657059
- Journal Information:
- Advanced Sustainable Systems, Vol. 1, Issue 9; ISSN 2366-7486
- Publisher:
- WileyCopyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
Effects of chain length on the size, stability, and electronic structure of redox-active organic–inorganic hybrid polyoxometalate micelles
|
journal | January 2019 |
Synthesis, Crystal Structures, and Thermal Properties of Protic Metal-Containing Ionic Liquids, Diethanolammonium Halometallates: (HOCH2CH2)2NH2FeCl4 and ((HOCH2CH2)2NH2)2CoCl4
|
journal | April 2020 |
Crossover in Membranes for Aqueous Soluble Organic Redox Flow Batteries
|
journal | January 2019 |
Similar Records
Theoretical and Experimental Investigation of Functionalized Cyanopyridines Yield an Anolyte with an Extremely Low Reduction Potential for Nonaqueous Redox Flow Batteries
Tuning the Stability of Organic Active Materials for Nonaqueous Redox Flow Batteries via Reversible, Electrochemically Mediated Li + Coordination