A sub-neutral aqueous electrolyte with pH buffering effect for the stable and reversible zinc metal electrochemistry

A sub-neutral aqueous electrolyte with buffering effect is desirable to stabilize the electrolyte pH value and achieve the reversible zinc storage. Herein, a pH-buffered zinc acrylate/sodium acrylate electrolyte (Zn(AA)₂/NaAA) are well-proposed, which regulate the electrolyte pH value to be stable at ∼5.1 without any acid-base reagent additives. The molecular dynamics simulation results demonstrate that the acrylate anions in the (Zn(AA)₂/NaAA) electrolyte participate in the coordination of Zn²⁺. The weakly-solvated zinc ion structure effectively weakens the zinc metal corrosion and hydrogen evolution reaction. Therefore, the assembled Zn-NaV₃O₈·1.5H₂O with (Zn(AA)₂/NaAA) battery exhibits the excellent stability over a wide range of current densities (1–5 A g⁻¹). This work provides new insights to design the novel aqueous electrolyte salt for the reversible zinc storage.