Everything in aqueous zinc-ion batteries may be Prussian blue analogues: From cathode materials to electrolyte additives applications

Aqueous zinc-ion batteries (AZIBs) have shown great potential in large-scale storage applications, owing to their inherent cost-effectiveness, higher operational safety, and eco-friendly characteristics. Prussian blue analogues (PBAs) have emerged as promising cathode candidates on account of their distinctive 3D open framework structure and superior energy storage capacity. However, PBAs still face problems such as poor conductivity, dissolution of transition metal (TM) ions, and the effect of crystal water in practical applications. To address these challenges, this article reviews the crystal structures, energy storage mechanisms and modification strategies of different metal-based PBAs in detail, covering ions doping, structural engineering, composite materials and electrolyte optimization to effectively enhance the electrochemical performance of PBAs. In addition, this review systematically summarizes the multi-functional application scenarios of PBAs in AZIBs, including innovative research progress as cathode materials, Zn anode protective layers, functional separators and electrolyte additives. Finally, the practical application challenges, future development and application prospects of PBAs materials in AZIBs are discussed. This review aims to provide guidance and assistance for the further development of AZIBs.