Diethylene glycol dimethyl ether effectively regulates the electrochemical behavior of zinc anode

A non-proton polar solvent Diethylene glycol dimethyl ether(DGDE) was used as a cosolvent in aqueous electrolyte, the strong binding of O lone pair electrons in the C-O bond to Zn2+ enabled DGDE to participate in the first solvent sheath to reconstruct the Zn2+ solvation structure. Meanwhile, the adsorption of DGDE on the surface of zinc electrode and the steric hindrance effect of DGDE molecule induced the horizontal deposition of hexagonal Zn(002) crystal plane, suppressed the zinc dendrite growth, while formed a dense protective layer on the surface of the zinc electrode to avoid it from the corrosion by the electrolyte. The initial CE of Zn||Cu semi -battery was increased from 77 % with pure ZnSO4 electrolyte to 87 % with 0.1 M DGDE added at 0.5 mA cm-2 and 1 mAh cm-2, and the average CE at 1 mA cm-2 and 1 mAh cm-2 was maintained at 98.7 % during the long cycle. As cycled at 3C (1C = 308mAh g-1) in 0.1 M DGDE electrolyte, Zn||epsilon-MnO2 full battery demonstrated much slower discharge decay, after 580 cycles, the capacity retained 138mAh g-1, 3.5 times of the system of 1 M ZnSO4. Adding trace DGDE to aqueous electrolyte can effectively improve CE and inhibit the zinc dendrite growth, not only maintains the low-cost, quick assembly advantages of aqueous zinc-ion battery, but also lays a foundation for its further application.