LAUSR

Aqueous rechargeable Na-ion batteries (ARNBs) hold great promise for grid-scale electric energy storage because of their outstanding merits of low cost and resource abundance; however, their low energy density and poor cycling stability limit practical application. In this work, we reported a Prussian Blue (PB) analogue Na2Zn3[Fe(CN)6]2 as a high-voltage aqueous cathode for ARNBs and achieved its stable cycling at a high operation potential of 1.13 V (vs SHE) by using of a highly concentrated NaClO4 electrolyte. Raman spectroscopy, in situ XRD, and DFT calculations have been utilized to study the underlying mechanism of electrode performance as a function of electrolyte concentration. It was revealed that in the concentrated 17 m NaClO4 electrolyte almost all the water molecules are coordinated with Na+ ions, and the solvation energy of PB materials increases considerably with increasing salt concentrations, which broadens the electrochemical stability window of the electrolyte and greatly alleviates the ...