Synergistic effect of hydrogen-bond interaction and interface regulation for stable aqueous sodium-ion batteries

Abstract

The narrow voltage window of aqueous electrolytes hinders the energy density of aqueous sodium-ion batteries (SIBs). Herein, a thermally and electrochemically stable hybrid electrolyte is developed with NaCF₃SO₃, 1,3-dioxolane (DOL), urea and H₂O. The intermolecular interactions between DOL, urea and H₂O regulate the hydrogen-bond network. Furthermore, the formation of an interfacial layer between the electrode and the electrolyte enables stable cycling of the manganese-based Prussian blue analogs (NaFeMnPBAs). As a result, a NaFeMnPBAs‖NaTi₂(PO₄)₃ full cell is constructed and it exhibits high energy density and superior stability in the hybrid electrolyte.