A team of researchers from the City College of New York and Sandia National Laboratories (Contact: Timothy N. Lambert) examined the impact of different acetate-based super-concentrated (or “water-in-salt”) electrolytes on zinc electrochemical performance at currents and material utilizations of practical relevance to industry (0.3-8 mA/cm2 and ~20 mAh/cm2 respectively). Data was collected to understand the fundamental thermodynamics and electrochemical rate-limiting-steps of the technology. Their results revealed that water solvation is not the reason for water-in-salt electrolyte stability but is rather due to a solid-electrolyte-interface (SEI) layer. This SEI layer also becomes the major limitation to practical battery charge/discharge rates. The team also explored strategies to overcome this hurdle, along with various cathode technologies for this electrolyte. The results were presented in an article titled “Electrochemical and Cycle Analysis of Water-in-Salt K-Acetate Electrolyte Zn-Ion Batteries Under Commercially-Relevant Conditions” and were published in the Journal of Electrochemical Society on July 15, 2024.
Decarbonization of national-scale electrical grids requires massive deployment of energy storage, a leading option for which is electrochemical-based batteries. For widespread adoption of grid-scale batteries to succeed, improvements to battery state-of-the-art are necessary in terms of affordability and safety. Toward this goal, this work researched aqueous electrolyte zinc-ion rechargeable batteries due to their low-cost materials, lack of thermal runaway risk, and inherent non-flammability. The major hurdle for aqueous electrolytes to overcome is lower energy density compared to the leading Li-ion technologies, due to the narrow stability window of aqueous electrolyte.
This research explored the use of a super-concentrated (or “water-in-salt”) aqueous electrolyte to expand the voltage window of operation. Their results showed encouraging results that may help pave the development pathway toward creating safe, low-cost, high-performance batteries of the future. The team of researchers included:
- Damon E. Turney, CUNY Energy Institute, City University of New York
- Debayon Dutta, CUNY Energy Institute, City University of New York
- Sanjoy Banerjee, CUNY Energy Institute, City University of New York
- Timothy N. Lambert, Sandia National Laboratories, Department of Photovoltaics and Materials Technology and the Center for Integrated Nanotechnologies
- Nelson S. Bell, Sandia National Laboratories, Advanced Materials Laboratory
D. Turney, D. Dutta, S. Banerjee, T.N. Lambert, N.S. Bell “Electrochemical and Cycle Analysis of Water-in-Salt K-Acetate Electrolyte Zn-Ion Batteries Under Commercially-Relevant Conditions” J. Electrochem. Soc. 171 070525 (2024) DOI: 10.1149/1945-7111/ad5769.
This material is based upon work supported by the U.S. Department of Energy, Office of Electricity (OE), Energy Storage Division. This work was performed, in part, at the Center for Integrated Nanotechnologies, an Office of Science User Facility operated for the U.S. Department of Energy (DOE) Office of Science.