Reconstruction of nitrogen-containing covalent organic framework-coordinated Ir single-atom electrocatalysts for high-performance lithium-rich oxygen battery cathodes

Abstract

Isolated single-atom catalysts (SACs) have attracted great interest due to their remarkable catalytic properties, but due to their high surface free energy, single atoms are highly mobile and tend to aggregate during their synthesis and catalytic processes. To reduce the pressure of the metal amount on the catalysts, lower the overpotential, and increase the rate of oxidation and reduction process, a new catalytic support material called covalent organic framework (COF) and a catalyst comprised of both iridium single atoms and nanoparticles embedded in a covalent organic framework (Ir/COF SA/NP) was proposed to provide a cathode host for lithium-rich oxygen batteries. The coin cell showed excellent electrochemical performance in terms of decreased charge/discharge polarization, a high reversible specific capacity of 476 mA h g⁻¹ at 0.1 C, high-rate capacity of 408 mA h g⁻¹ and excellent capacity retention of 83.3% after 100 cycles at 1 C. This cathode composite material showed the best electrochemical performance among related cathode composites.