Critical design strategy of electrolyte engineering toward aqueous zinc-ion battery

In virtue of cost-effectiveness, high security and environmental-friendly, aqueous zinc-ion batteries (ZIBs) are considered as one of the most promising energy storage devices, but suffer from fundamental scientific questions such as dendrite growth, hydrogen evolution reaction, by-product generation and cathode dissolution. Electrolyte, a significant component of ZIBs, provides the necessary medium for zinc-ions transport between cathode and anode. Thus, electrolyte engineering has been proved to be an effective strategy to achieve high-performance of ZIBs. Herein, electrolyte optimization strategies from the perspective of both endogenous (intrinsic properties of the electrolyte salt in aqueous and gel electrolytes) and exogenous factors (the solvation structure modulation and electrode/electrolyte interface optimization during zinc-ions transport) are comprehensively reviewed. The designing principles of electrolyte salt for different cathode materials, optimization strategies of solvation structure and interface in terms of charge storage and transport kinetic characteristics are emphasized. Based on the key relationship between the issues and modified strategies, the improved electrochemical performances are revealed. Furthermore, to accelerate the development of high-performance ZIBs in the future, the new insights and relevant potential directions are also presented.