The Dual Role of Halides in Zinc-Air Batteries: From Catalytic Modulator to Electrolyte Stabilizer.

Zinc-air batteries (ZABs) can effectively mitigate the over-exploitation of fossil fuels and the inherent safety issues associated with lithium-ion batteries (LIBs). However, their practical implementations remain constrained by some challenges, including sluggish oxygen reduction/evolution reaction (ORR/OER) kinetics and insufficient electrochemical stability of conventional electrolyte systems. Halogens and halides have multiple advantages, whether it is the strong electronic modulation capability possessed by F, the modification of electrolytes by Cl and Br, or the replacement of OER by the iodine oxidation reaction (IOR), all of which can solve various pain points for high-performance ZABs. Based on these advantages, the review systematically summarizes the research advancements of halogens and halides in ZABs. First, the review provides a concise overview of ZABs. Subsequently, from the perspectives of component modulation, defect engineering, interface regulation, and electrolyte modification, the review elaborates in detail the multifaceted regulatory mechanisms of fluorine, chlorine, bromine, and iodine and their compounds in enhancing catalytic activity and optimizing battery performance. Finally, the review summarizes the synergistic effects in halogen systems, outlines the remaining challenges, and offers some valuable insights for designing high-efficiency ZABs, while holding significant implications for advancing sustainable renewable energy storage technologies.