Regulating the Solvation Structure of Potassium Ions Using a Multidentate Ether in Potassium Metal Batteries

Potassium (K) is regarded as an alternative to lithium (Li) for use in contemporary energy storage devices owing to its high abundance and low electrochemical potential. However, because K ions are larger than Li ions, they exhibit different solvation properties that can ultimately affect device performance. Herein, a multidentate ether-based electrolyte is demonstrated to effectively solvate K ions and the solvation structures can be further modulated with cosolvents. The use of the multidentate ether-based electrolyte also suppresses the formation of K dendrites and significantly enhances the cycling stability of K//K symmetric cells (e.g., over 2000 h at 0.25 mA cm–2).