Interfacial engineering-boosted oxygen electrocatalysts of Fe-Fe3N@NCNTs for rechargezable zinc-air batteries

Fe-Fe 3 N@NCNTs exhibits half-wave potential at 0.92 V. • Fe-Fe 3 N@NCNTs shows a shift of only 15 mV after 30k cycles. • DFT and in-stiu Raman confirm Fe-Fe 3 N tunes adsorption energy to enhance ORR activity. • Fe-Fe 3 N@NCNTs-assembled ZABs have excellent potential for applications. : Interface engineering is regarded as a pivotal technique for overcoming the activity-stability trade-off in Fe-based oxygen reduction reaction (ORR) catalysts. Herein, a bifunctional catalyst of Fe-Fe 3 N@NCNTs heterostructure is synthesized through a simple one-step calcination method. The catalyst exhibits a remarkable half-wave potential of 0.92 V vs RHE for ORR with only 15 mV decay over 30k cycles and overpotential of 310 mV for OER. In-situ Raman and density functional theory (DFT) reveal that the electronic modulation of Fe-Fe 3 N hetero-interface activates Fe-N and C-N dual sites synergistically and achieves optimal intermediate adsorption strength, significantly lowering energy barrier of rate determine step. The assembled zinc–air batteries (ZABs) with Fe-Fe 3 N@NCNTs exhibit a high power density of 252.5 mW cm -2 and remarkable durability of 2400 h, while the corresponding flexible solid-state ZABs deliver excellent rate capability and robust stability over 1000 cycles. This work provides new insights into the design of advanced heterostructure electrocatalysts for practical energy storage applications. The prepared Fe-Fe 3 N@NCNTs composite catalyst leverages the synergistic effect between Fe and Fe 3 N, which optimizes both the structure and electron density. The unique structure significantly enhances the ORR/OER activity, enabling zinc–air batteries to achieve high power density, high specific capacity, and exceptional cycle life, demonstrating substantial promise for energy conversion and storage applications. Download: Download high-res image (453KB) Download: Download full-size image