Thin-Film Electrolytes for High-Energy-Density and Low-Cost Polychalcogenide-Based Redox Flow Batteries
- MilleniTEK LLC
- MillenniTEK LLC
- Georgia Institute of Technology, Atlanta, GA (United States)
The overall objective of this research project is to develop a new type of sodium-sulfur redox flow battery for grid-scale energy storage. The advantages of this type of battery are: High energy density and efficiency (up to 90%) Long discharge cycles (> 10 hours) Long life (> 10 years) Low cost and domestic availability of Na and S Potential to decouple power and energy Better safety compared to incumbent battery technology If successful, this technology has the potential to combine the advantages of a vanadium redox flow battery with high temperature molten sodium-sulfur batteries, both of which have been tested at MW scale in the field. The main issue preventing the use of this type of battery currently is the high operating temperature needed for Na-S chemistry. This is driven by two factors. First, the ionic conductivity of Na+ conducting ceramic electrolytes increases with temperature, so high temperature is needed for high efficiency. Second, the wettability and surface contact of Na on the electrolyte is poor at low temperature. This project addresses both factors. First, by forming a thin electrolyte membrane supported by a thick, porous support layer. Second, by developing anolyte and catholyte solutions that have improved wettability on the solid electrolyte, while maintaining a high energy density. In Phase I of this project, we have demonstrated the following: (1) A process to form a tubular electrolyte membrane supported by a porous support, where the membrane is made from the sodium ion conducting ceramic NASICON (Na3Zr2Si2PO12). This material is significant because it is water-compatible and could therefore be used with an aqueous anolyte/catholyte system (2) Room temperature operation using an intermediate materials system, Na-β''-Al2O3 (BASE) electrolyte with a nonaqueous anolyte/catholyte that has an energy efficiency of 95% and performance degradation of 6.4% over 110 cycles. The goal for this project was > 85% efficiency, and degradation of < 8% over 200 cycles. (3) A lab-scale flow battery test setup that could be used as a test platform in Phase II. We propose continuing this work in Phase II by improving the performance of this material system to be competitive with vanadium redox flow batteries, and building a 250 W prototype system.
- Research Organization:
- MillenniTEK LLC
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES)
- DOE Contract Number:
- SC0021597
- OSTI ID:
- 1834004
- Type / Phase:
- STTR (Phase I)
- Report Number(s):
- DOE-MTEK-21597
- Country of Publication:
- United States
- Language:
- English
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