Researchers in the Manthiram Research Group have developed a new way to overcome a key compatibility challenge in sodium-metal batteries. Ether-based electrolytes work well with highly reactive sodium metal, but they tend to break down at the high voltages needed for higher-energy batteries. Zhiming Zhao, a research associate in the group, Dr. Arumugam Manthiram, and TMI scientist Dr. Andrei Dolocan have developed a new electrolyte chemistry that allows ether-based electrolytes to operate with high-voltage cathodes while maintaining stable sodium-metal cycling.
Their approach generates an asymmetric boron-based molecule directly within the electrolyte. The molecule reacts differently at the two electrodes. At the positive electrode, it forms a thin protective layer that helps prevent the ether electrolyte from breaking down at high voltage. At the sodium-metal electrode, it forms another protective layer that helps sodium deposit and dissolve more uniformly during repeated charging and discharging. Together, these protective layers enable highly reversible battery cycling.
By designing an electrolyte component that creates different protective environments at the two electrodes, the researchers were able to combine the advantages of sodium metal with the high-voltage operation needed for higher-energy batteries.
Read more at their article, "High-Voltage Sodium–Metal Batteries with Asymmetric Fluoroalkoxylated Organoborate Anion Chemistry," in the Journal of the American chemical Society.
