A Dual Organic Solvent Zn-Ion Electrolyte Enables Highly Stable Zn Metal Batteries

Aqueous zinc (Zn) batteries have been regarded as analternativeto lithium-ion batteries due to their high abundance, low cost, andhigher intrinsic safety. However, the low Zn plating/stripping reversibility,Zn dendrite growth, and continuous water consumption have hinderedthe practical application of aqueous Zn anodes. Herein, a hydrousorganic Zn-ion electrolyte based on a dual organic solvent, namelyhydrated Zn(BF4)(2) zinc salt dissolved in dimethylcarbonate (DMC) and vinyl carbonate (EC) solvents [denoted as Zn(BF4)(2)/DMC/EC], can address these problems, which notonly inhibits the side reactions but also promotes uniform Zn plating/strippingthrough the formation of a stable solid state interface layer andZn(2+)-EC/2DMC pairs. This electrolyte enables the Zn electrodeto stably undergo >700 cycles at a rate of 1 mA cm(-2) with a Coulombic efficiency of 99.71%. Moreover, the full cell pairedwith V2O5 also demonstrates excellent cyclingstability without capacity decay at 1 A g(-1) after1600 cycles.