A Dual Organic Solvent Zn-Ion Electrolyte Enables Highly Stable Zn Metal Batteries
Ruiqi He, Fangfang Yu, Kuan Wu, Haoxuan Liu, Zhen Li, Huan Liu, Shi Xue Dou, Chao Wu
Abstract
Aqueous zinc (Zn) batteries have been regarded as an alternative to lithium-ion batteries due to their high abundance, low cost, and higher intrinsic safety. However, the low Zn plating/stripping reversibility, Zn dendrite growth, and continuous water consumption have hindered the practical application of aqueous Zn anodes. Herein, a hydrous organic Zn-ion electrolyte based on a dual organic solvent, namely hydrated Zn(BF 4 ) 2 zinc salt dissolved in dimethyl carbonate (DMC) and vinyl carbonate (EC) solvents [denoted as Zn(BF 4 ) 2 /DMC/EC], can address these problems, which not only inhibits the side reactions but also promotes uniform Zn plating/stripping through the formation of a stable solid state interface layer and Zn 2+ -EC/2DMC pairs. This electrolyte enables the Zn electrode to stably undergo >700 cycles at a rate of 1 mA cm –2 with a Coulombic efficiency of 99.71%. Moreover, the full cell paired with V 2 O 5 also demonstrates excellent cycling stability without capacity decay at 1 A g –1 after 1600 cycles.