Regulation of Outer Solvation Shell Toward Superior Low-Temperature Aqueous Zinc-Ion Batteries.

Abstract

Aqueous Zn-ion batteries are well regarded among a next-generation energy-storage technology due to their low cost and high safety. However, the unstable stripping/plating process leading to severe dendrite growth under high current density and low temperature impede their practical application. Herein, it is demonstrated that the addition of 2-propanol can regulate the outer solvation shell structure of Zn2+ by replacing water molecules to establish a "eutectic solvation shell", which provides strong affinity with the Zn (101) crystalline plane and fast desolvation kinetics during the plating process, rendering homogeneous Zn deposition without dendrite formation. As a result, the Zn anode exhibits promising cycle stability over 500h under an elevated current density of 15mAcm-2 and high depth of discharge of 51.2%. Furthermore, remarkable electrochemical performance is achieved in a 150mAh Zn|V2 O5 pouch cell over 1000 cycles at low temperature of -20°C. This work not only offers a new strategy to achieve excellent performance of aqueous Zn-ion batteries under harsh conditions, but also reveals electrolyte structure designs that can be applied in related energy storage and conversion fields.