Lithium Ion Conduction in Covalent Organic Frameworks

Ion conduction plays key roles in electrochemical systems, including fuel cells, lithium ion batteries, and metal-air batteries. Covalent organic frameworks (COFs), as a new class of porous polymers, constructed by pre-designable building blocks, are ideal hosts to accommodate ionic carries for conduction because of their straightforward pore channels, tunable pore size, controllable pore environment, and good chemical and thermal stability. Different from proton conduction, how to achieve high lithium ion conduction is still a challenge as it is difficult to dissociate ionic bonds of the lithium salts. To facilitate the dissociation of lithium salts, COFs with different pores and skeletons are well designed and constructed. This review focuses on emerging developments of lithium ion conduction in COFs, and discusses the structures of these COFs and conductive performance to elucidate the structure-property correlations. Furthermore, we have concluded the remaining challenge and future direction in these COF-based lithium conductive areas. This review provides deeper insight into COFs for ionic conduction.