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). © 2022 American Chemical Society. All rights reserved.