Engineering Electronic Spin State of a CoNi Alloy for an Efficient Oxygen Reduction Reaction

Developing cost-effective electrocatalysts for oxygen reduction reaction (ORR) is of great importance to improve the performance of metal-air batteries. Herein, a CoNi alloy encapsulated in an N-doped carbon framework (CoNi@NC) with a high saturation magnetization (89.1 emu g(-1)) is prepared by nanoalloying, and an external magnetic field is employed to directly enhance the ORR performance of CoNi@ NC. The electronic structure of CoNi@NC is greatly optimized by electron cloud redistribution and spin-state adjustment, leading to Pt/C-comparable ORR performance in an alkaline electrolyte (the onset potential of 0.98 V and half-wave potential of 0.86 V in 0.1 M KOH). Furthermore, the CoNi@NC-based Al-air battery with magnet delivers a larger power density of 161.27 mW cm(-2) and exhibits better durability compared with those with Pt/C. This work provides a promising approach to using magnetic induction to enhance oxygen reduction activity for metal-air batteries.

Automated summary

Developing cost-effective electrocatalysts is crucial in improving the performance of metal-air batteries. In this study, a CoNi alloy encapsulated in an N-doped carbon framework (CoNi@NC) with high magnetization was prepared using nanoalloying, and an external magnetic field was used to enhance the ORR performance. The electronic structure of CoNi@NC was optimized, resulting in Pt/C-comparable ORR performance. The CoNi@NC-based Al-air battery with magnet exhibited higher power density and better durability compared to Pt/C. This work provides a promising approach to enhancing oxygen reduction activity for metal-air batteries using magnetic induction.