Covalent Organic Frameworks as Cathode Materials for Metal Ion Batteries

Covalent organic frameworks (COFs) are porous organic materials with periodic two-dimensional or three-dimensional network structures consisting of two or more organic molecules connected by covalent bonds. COFs have attracted considerable interest in energy storage due to their beneficial properties, including low skeletal density, high surface area, high porosity, structural designability and functional modifiability. COFs offer unique advantages as positive electrode materials for metal ion batteries due to their rich redox active sites and open framework structure. However, their application in energy storage is limited by challenges such as poor conductivity, low energy density, limited number of available active sites, and blockage of ion transport channels. This article provides a comprehensive review of recent research on COFs as positive electrode materials for metal ion batteries, discussing their types, design strategies, and synthesis methods . Additionally, it presents an overview of the electrochemical energy storage mechanisms from the perspective of different active groups, and the applications of COFs in various metal ion batteries. Finally, it highlights the prospects and challenges of using COFs in energy storage