Recent Progress of Hexaazatriphenylene-based Electrode Materials for Rechargeable Batteries

pi-Conjugated organic electrode materials (OEMs) attract numerous attentions for rechargeable batteries, owing to their unprecedentedly high theoretical capacity, flexible structure designability, environmental friendliness and elemental abundance. The essential rigid coplanar hexaazatriphenylene (HAT) building blocks with high density C=N functional groups, not only facilitate the delocalization of molecular orbitals for energy band engineering, but also impose fast kinetics, good cycling stability, as well as facile and large-scale production with low cost. In this Minireview, we start with a general overview of the design strategies of HATs, involving both small molecules and polymers, followed by the working principles and mechanisms of recent HAT OEMs. Subsequently, we present a comprehensive section focusing the fundamental electrochemical properties (output voltage, capacity, cycling stability, and rate performance) and optimization of HAT OEMs, with various ionic charge carriers in different batteries. Finally, the critical challenges and perspectives of HAT OEMs are discussed, aiming to develop practical batteries in both organic and aqueous electrolytes, towards high energy density, high stability, fast kinetics, and low cost. This Minireview provides insights into the development of heteroaromatic HAT OEMs with high performance for next-generation rechargeable batteries.