Recently, the increasing concerns regarding environmental and energy-related issues due to the use of fossil fuels have triggered extensive research on sustainable electrochemical energy storage and conversion (EESC). In this case, covalent triazine frameworks (CTFs) possess a large surface area, tailorable conjugated structures, electron donating–accepting/conducting moieties, and excellent chemical and thermal stabilities. These merits make them leading candidates for EESC. However, their poor electrical conductivity impedes electron and ion conduction, leading to unsatisfactory electrochemical performances, which limit their commercial applications. Thus, to overcome these challenges, CTF-based nanocomposites and their derivatives such as heteroatom-doped porous carbons, which inherit most of the merits of pristine CTFs, lead to excellent performances in the field of EESC. In this review, initially, we briefly highlight the existing strategies for the synthesis of CTFs with application-targeted properties. Next, we review the contemporary progress of CTFs and their derivatives related to electrochemical energy storage (supercapacitors, alkali-ion batteries, lithium–sulfur batteries, etc.) and conversion (oxygen reduction/evolution reaction, hydrogen evolution reaction, carbon dioxide reduction reaction, etc.). Finally, we discuss perspectives on current challenges and recommendations for the further development of CTF-based nanomaterials in burgeoning EESC research.
Covalent triazine framework (CTF) derivatives have emerged as promising metal-free electrocatalysts due to their high nitrogen content and intrinsic porosity. However, their performance remains limited by sluggish interfacial charge transport and the inaccessibility of active sites. Herein, we report an interfacial covalent bridging strategy based on grafting polymerization to construct a carbon heterostructure electrocatalyst, featuring vertically aligned nitrogen-doped nanosheets covalently anchored onto graphene (v-N/CNS/Gr) support. The covalently bridged interface promotes interfacial charge transfer across the heterostructure, activating otherwise dormant nitrogen active sites and amplifying the oxygen reduction reaction (ORR) reactivity. In situ spectroscopic analyses and theoretical simulations reveal that the covalent bridged bonding promotes charge transport and oxygen activation, and optimizes the adsorption/desorption of intermediates, collectively contributing to reduced energy barriers along the 4e- ORR pathway. As a result, the v-N/CNS/Gr delivers excellent ORR activity with a half-wave potential of 0.85 V (vs RHE). When employed as the cathode in a Zn-air battery, v-N/CNS/Gr achieves a high-power density and stable operation over 850 h. This work demonstrates a generalizable triazine-polymer-based interfacial bridge strategy for enhancing active site accessibility and charge transport in metal-free electrocatalysts.