Low‐cost and Non‐flammable Eutectic Electrolytes for Advanced Zn‐I2 Batteries

As a burgeoning electrolyte system, eutectic electrolytes based on ZnCl2/Zn(CF3SO3)2/Zn(TFSI)2 have been widely proposed in advanced Zn‐I2 batteries; however, safety and cost concerns significantly limit their applications. Here, we report new‐type ZnSO4‐based eutectic electrolytes that are both safe and cost‐effective. Their universality is evident in various solvents of polyhydric alcohols, in which multiple −OH groups not only involve in Zn2+ solvation but also interact with water, resulting in the high stability of electrolytes. Taking propylene glycol‐based hydrated eutectic electrolyte as an example, it features significant advantages in non‐flammability and low price that is