Self-Assembled Covalent Triazine Frameworks Derived N, S Co-Doped Carbon Nanoholes with Facilitating Ions Transportation Toward Remarkably Enhanced Oxygen Reduction Reaction and for Zinc–Air Batteries

Abstract

3D assembled carbon materials, featuring unique hierarchical porosity and interconnected channels, are essential for the advancement of emerging zinc–air batteries (ZABs). In this study, nitrogen (N) and sulfur (S) co-doped 3D carbon nanoholes (N/S-CNHs) are synthesized through a straightforward procedure involving self-assembly followed by carbonization. This process utilizes a hybrid of self-assembled covalent triazine framework and sodium lignosulphonate (CTF@LS) as a multifunctional precursor. The resulting N/S-CNHs exhibit a distinctive nanoholes microstructure composed of interwoven carbon nanoclusters, which facilitates efficient ion and electron transport during the electrocatalytic process. The incorporation of N and S atoms intriguingly alters the wetting properties of the catalyst microenvironment, thereby significantly facilitating the transfer of key intermediates and their interaction with the electrolyte. Consequently, the optimized N/S-CNH-900 demonstrates remarkable electrocatalytic activity for the ORR (E_1/2 = 0.86 V vs RHE), surpassing the performance of state-of-the-art Pt/C electrocatalyst. Theoretical calculations reveal that the synergistic effect of N and S heteroatom doping significantly enhances *OOH desorption and its transformation to O*, thereby markedly accelerating the ORR process. Furthermore, both liquid and quasi-solid ZABs equipped with the N/S-CNH-900 cathode exhibit improved peak power density and specific capacity relative to those employing commercial Pt/C catalysts.