Synergistic Effects between Doped Nitrogen and Phosphorus in Metal-Free Cathode for Zinc-Air Battery from Covalent Organic Frameworks Coated CNT

Abstract

A covalent organic framework that is composed of hexachlorocyclotriphosphazene and dicyanamide has been coated on CNT to prepare metal-free oxygen reduction reaction catalyst through thermal polymerization of the Zn-air battery cathode. The N,P-codoped nanohybrids have highly porous structure and active synergistic effect between graphitic-N and -P, which promoted the electrocatalytic performance. The electrocatalysts exhibits remarkable half-wave potential (-0.162 V), high current density (6.1 mA/cm), good stability (83%), and excellent methanol tolerance for ORR in alkaline solution. Furthermore, the N,P-codoped nanohybrids were used as an air electrode for fabrication of a high performance Zn-air battery. The battery achieves a high open-circuit potential (1.53 V) and peak power density (0.255 W cm). Moreover, the effect of N,P codoping on the conjugate carbon system and the synergistic effect between graphitic-N and P have been calculated through density functional theory calculations, which are essentially in agreement with experimental data.

Recent Advances in Materials and Design of Electrochemically Rechargeable Zinc–Air Batteries

“…The same research group further used an inorganic salt (NaCl) to create web‐like structures in carbon materials, leading to increased surface area and improved mass transfer . Li et al coated a covalent organic framework comprised of hexachlorocyclotriphosphazene and dicyanamide on CNTs, which yielded an N, P‐codoped nanohybrid . Luo et al used potassium phytate as a carbonaceous precursor to synthesize porous carbon materials codoped with N and P. It was proposed that the formation of K 4 P 2 O 7 help to self‐terminate the carbon activation, resulting in a low material weight loss less than 17% .…”

Metal-free activation of molecular oxygen by covalent triazine frameworks for selective aerobic oxidation

“…4D. So far, many experimental and theoretical investigations have shown the applicability of N-doped carbon-based materials for adsorption and activation of molecular O 2 (6,(59)(60)(61)(62). Within this context, Arai and co-workers (48) proposed the adsorption of molecular oxygen on a carbon atom neighboring the quaternary N atom and/or on the carbon and nitrogen atoms, which results in the formation of some oxygen radicals.…”

Recent advances in hybrid sodium–air batteries

“…MOF-derived nanostructured materials are promising bifunctional electrocatalysts owing to their large specific surface area, robust morphology, and porosity [173]. Li et al [174] [178] synthesized N, P-containing MOF coated on CNTs as high-performance catalysts (Fig. 14b).…”