摘要
Aqueous zinc(Zn)-metal cells with cost-effective components and high safety have long been a promising large-scale energy storage system,but Zn anodes are intrinsically unstable with common aqueous electrolytes,causing substantial underutilization of the theoretical capacity.In this work,we report a strictly neutral aqueous Zn electrolyte at a low cost by leveraging the dynamic hydrolysis equilibrium of a dual-salt Zn(Ac)2/NaAc(Ac:CH3COO−)formulation.With the pH regulation,the corrosion and hydrogen evolution encountered in Zn anodes can be suppressed significantly.This hybrid aqueous electrolyte not only enables dendrite-free Zn plating/stripping at a nearly 95%Coulombic efficiency[an increase of 24%compared to that of the single-salt 1 mol/L Zn(Ac)2 electrolyte],but also supports the reversible operation of Zn cells paired with either Na3V2(PO4)3 or iodine cathodes—the former delivers a high output voltage of 1.55 V with an energy level of 99.5 W·h/kg(based on the mass of the cathode),and the latter possesses a high specific capacity of 110.9 mA·h/g while yielding long-term cyclability(thousands of cycles).These findings open up a new avenue of modifying practical electrolytes having targeted properties to stabilize multivalent metal anodes.
基金
This work was supported by the National Key R&D Program of China(No.2017YFE0127600)
the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA21070304)
the National Natural Science Foundation of China(Nos.U1706229,21975271)
the Taishan Scholars of Shandong Province,China(No.ts201511063)
the Youth Innovation Promotion Association of Chinese Academy of Sciences(No.2019214)
the QIBEBT(No.ZZBS201808).
