Efficient proton conduction in porous and crystalline covalent-organic frameworks (COFs)

To attain the objectives of carbon peaking and carbon neutrality, the development of stable and high-performance ion-conducting materials holds enormous relevance in various energy storage and conversion devices. Particularly, crystalline porous materials possessing built-in ordered nanochannels exhibit remarkable superiority in comprehending the ion transfer mechanisms with precision. In this regard, covalent organic frameworks (COFs) are highly regarded as a promising alternative due to their pre-eminent structural tunability, accessible well-defined pores, and excellent thermal/chemical stability under hydrous/anhydrous conditions. By the availability of organic units and the diversity of topologies and connections, advances in COFs have been increasing rapidly over the last decade and they have emerged as a new field of proton-conducting materials. Therefore, a comprehensive summary and discussion are urgently needed to provide an “at a glance” understanding of the prospects and challenges in the development of proton-conducting COFs. In this review, we target a comprehensive review of COFs in the field of proton conductivity from the aspects of design strategies, the proton conducting mechanism/features, the relationships of structure–function, and the application of research. The relevant content of theoretical simulation, advanced structural characterizations, prospects, and challenges are also presented elaborately and critically. More importantly, we sincerely hope that this progress report will form a consistent view of this field and provide inspiration for future research.