A team of scientists at the U.S. Department of Energy‘s Argonne National Laboratory has made an important discovery regarding the behavior of complex component mixtures in batteries’ electrolytes. Electrolytes are materials that transport charged particles, known as ions, between a battery’s electrodes to convert stored chemical energy into electricity. The researchers found that combining different negatively charged ions, called anions, with positively charged ions, called cations, can significantly improve battery performance. This suggests that careful selection of ion mixtures can allow battery developers to customize their devices for specific performance characteristics.

The study focused on a type of next-generation battery called the multivalent battery, which uses cations such as zinc, magnesium, and calcium with a charge of +2 instead of the +1 charge of lithium ions used in current lithium-ion batteries. By moving more charge, multivalent batteries can store and release more energy, making them attractive for electric vehicles and grid storage. Additionally, multivalent batteries use abundant elements with stable domestic supply chains, unlike lithium, which has a limited supply and volatile international supply chain.

To optimize the performance of multivalent batteries, it is crucial to understand how ions interact with each other in the electrolyte. The researchers used advanced techniques such as X-ray absorption spectroscopy, Raman spectroscopy, and density functional theory to study the interactions and structures formed by zinc cations and different types of anions in the electrolyte. They discovered that certain anions induced the pairing of anions with zinc cations, which affected the rate at which the cations could be deposited as metal on the battery’s anode during charging and subsequently stripped back into the electrolyte during discharge. This finding could lead to the design of electrolytes that enhance cation transport, increase electrode stability and activity, and enable faster and more efficient electricity generation and storage.

The researchers also highlighted the importance of exploring different anion mixtures in batteries to fine-tune their interactions with cations. They suggested that machine learning could be used to rapidly calculate the interactions and select the most promising combinations of ions for further experimental investigation. The upgrade of the Advanced Photon Source, a synchrotron X-ray facility, will enable more advanced analyses of electrolyte behaviors and contribute to further advancements in battery research.

Overall, this research provides valuable insights into the design of electrolytes for advanced batteries and opens up new possibilities for improving battery performance and stability.

This new research was published in Chem.

References

• Driscoll, D. M., Lavan, S. N., Zorko, M., Redfern, P. C., Ilic, S., Agarwal, G., Fister, T. T., Assary, R. S., Cheng, L., Strmcnik, D., Balasubramanian, M., & Connell, J. G. (2023). Emergent solvation phenomena in non-aqueous electrolytes with multiple anions. Chem, 9(7), 1955–1971. https://doi.org/10.1016/j.chempr.2023.03.021
• Matz, M. & Argonne National Laboratory. (2023, November 14). A new blueprint for designing high-performance batteries. TechXplore. https://techxplore.com/news/2023-11-blueprint-high-performance-batteries.html