Critical roles of metal-organic frameworks in improving the Zn anode in aqueous zinc-ion batteries

Due to their high energy density, safety, and low cost, rechargeable aqueous zinc-ion batteries (AZIBs) have recently gained much interest. Issues, however, such as anode side reactions, passivation, corrosion, hydrogen evolution, and Zn dendrite growth, continue to pose significant barriers to further AZIBs applications. Herein, metal-organic frameworks (MOFs) are presented as potential candidates to suppress the above-mentioned problems effectively. Because of their multifunctional homogeneous porous structure and abundance of active sites with substantial surface areas, MOFs can enhance the performance of the Zn anode materials, electrolytes, and electrolyte additives. First, it emphasizes the inherent chemical characteristics, difficulties, and solvation of Zn anodes. Then, MOFs/MOF-derived anode grids or layers, anode modifications by MOFs and 3D host, MOF-based electrolytes, and separators are classified and compared in terms of structural and electrochemical properties, issues, and solutions. This review aims to provide potential directions and perspectives for the rational design of MOF-based Zn anodes and basic comprehension of the mechanisms affecting Zn2+ solvation in high-performance AZIBs. Finally, the challenges and opportunities of designing MOF-based Zn anodes are pro-posed to extend the cycling lifetime and promote the commercialization of AZIBs.

Automated summary

Rechargeable aqueous zinc-ion batteries (AZIBs) have gained much interest due to their high energy density, safety, and low cost. However, issues such as anode side reactions, passivation, corrosion, hydrogen evolution, and Zn dendrite growth continue to hinder their widespread application. This review presents metal-organic frameworks (MOFs) as potential solutions to these problems by enhancing the performance of Zn anode materials, electrolytes, and electrolyte additives through their porous structure and active sites. The review also proposes directions for the rational design of MOF-based Zn anodes and understanding the mechanisms affecting Zn2+ solvation in high-performance AZIBs, aiming to extend the cycling lifetime and promote the commercialization of AZIBs.