Functional Mechanisms and Screening Strategies of Electrolyte Additives for Stable Zinc-Ion Batteries

Aqueous zinc-ion batteries (AZIBs) are promising for sustainable energy storage due to their cost-effectiveness, high safety, and environmental compatibility. The Zn anode offers advantages of a low redox potential and high theoretical capacity yet faces critical challenges of side reactions and dendrite growth in aqueous electrolytes, which decreases the energy density and cycle life of AZIBs. The electrolyte optimization strategy of employing functional additives has emerged as a scalable solution to regulate the interfacial ionic and electric fields via improving the chemical environment and interface properties of the electrode, which serves as an effective pathway for the stable Zn anode. However, the practical application of this methodology is significantly constrained by the lack of an efficient screening principle. This Perspective reviews the functional mechanisms of additives, including electrostatic shielding, solvation modulation, and solid-electrolyte interphase (SEI) formation, and further proposes a novel evaluation metric, throwing power, to assess additive efficacy, which will advance the rational design of high-performance AZIBs.