Ultrafine Cu6Sn5 nanoalloys supported on nitrogen and sulfur-doped carbons as robust electrode materials for oxygen reduction and Li-ion battery

Abstract

Ultrafine Cu6Sn5 nanoalloys supported on porous N and S-doped carbons (Cu6Sn5@N–S–Cs) were prepared by annealing Cu–Sn-contained covalent organic frameworks (COFs). The Cu6Sn5 alloys with particle size of about 2–10 nm were formed on the surface of N–S–Cs in a high dispersion state. The Cu6Sn5@N–S–Cs were found to efficiently catalyze oxygen reduction reaction (ORR) in both alkaline and acidic media, with half-wave ORR potential (E1/2) of 0.86 V in 0.1 M KOH and 0.67 V in 0.1 M HClO4. The ORR performance of Cu6Sn5@N–S–C could be competitive to the best Fe (or Co)-based non-precious metal electrocatalysts and commercial Pt/C. Cu6Sn5@N–S–C also showed better durability for ORR in both media. Moreover, Cu6Sn5@N–S–C also possessed electrochemical lithium ion storage capacity of 905 mA h g−1 in an initial discharge at the current density of 50 mA g−1, with the outstanding coulomic efficiency. The synergistic effects of ultrafine Cu6Sn5 nanoalloys and porous N–S–Cs contributed to the impressive ORR performance and lithium storage capacities. COFs-derived Cu6Sn5@S–N–C was demonstrated to be a promising bifunctional electrode material for proton exchange membrane fuel cells and lithium ion batteries.