Abstract
Nonaqueous redox-flow batteries (NARFBs) that use economical alkali metals and the corresponding metal polysulfides are highly attractive for grid-scale energy storage. Although sodium-sulfur systems have been recognized as promising candidates and have been the focus of many studies due to their high earth abundance and energy density, an understanding of the role of the solvation chemistry of commonly used glyme solvents is missing. Herein, we report a systematic investigation into the solvation effects of glyme-based Na-S electrolytes through comprehensive physiochemical experiments and Density Functional Theory (DFT) simulations. Our findings revealed, on one hand, that an optimal coordination strength between glymes and Na+ could maintain a relatively smooth Na+ diffusion. On the other hand, glyme solvents with extended chain lengths shift the reduction potential of S82- negatively to elevate the formation barrier of undesirable short-chain polysulfides (Sn2-, n ≤ 4) that have high membrane permeability. This solvation phenomenon not only mitigates capacity fading but also extends the operational longevity of the Na-S NARFBs. The results underscore the critical roles of balanced solvent-cation interactions and controlled redox potentials in improving the stability and efficiency of Na-S NARFB systems, marking a significant advancement in the development of sustainable energy storage solutions.
| Original language | English |
|---|---|
| Pages (from-to) | 5795-5800 |
| Number of pages | 6 |
| Journal | ACS Energy Letters |
| DOIs | |
| State | Accepted/In press - 2024 |
Funding
This manuscript has been authored by UT-Battelle, LLC under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy. The United States Government retains and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a nonexclusive, paid-up, irrevocable, worldwide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes. The Department of Energy will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan ( http://energy.gov/downloads/doe-public-access-plan ). This material is based upon work supported by the U.S. Department of Energy, Office of Electricity (OE), Energy Storage Division. W.W. and L.C. acknowledge that the computational study was performed using computational resources sponsored by the Department of Energy\u2019s Office of Energy Efficiency and Renewable Energy and located at the National Renewable Energy Laboratory. We acknowledge the program directors, Dr. Caitlin Callaghan and Dr. Nyla Khan, as well as ORNL OE30 program manager Dr. Mali Balasubramanian, for their guidance, feedback, and support on the project. We also acknowledge Dr. Thomas Zawodzinski for the fruitful discussion.
| Funders | Funder number |
|---|---|
| U.S. Department of Energy | |
| Office of Energy Efficiency and Renewable Energy | |
| National Renewable Energy Laboratory | |
| Office of Electricity |
