Covalent organic frameworks: Design and applications in electrochemical energy storage devices

As an emerging class of crystalline organic material, covalent organic frameworks (COFs) possess uniform porosity, versatile functionality, and precise control over designated structures. Aside from the favorable charge and mass transport pathways offered by the porous framework, COFs can also exhibit designed reversible redox activity. In the past few years, their potential has attracted a great deal of attention for charge storage and transport applications in various electrochemical energy storage devices, and numerous design strategies have been proposed to enhance the corresponding electrochemical properties. This review summarizes the working principle and synthesis methods of COFs and discusses significant findings for supercapacitors and various rechargeable battery systems, emphasizing the representative design strategies and their underlying relationship with electrochemical performances. In addition, key advances achieved by computations are highlighted along with the challenges and prospects in this field.