Fe–Ni Conformational Self-Optimization Driven by Covalent Organic Polyemers for Superior Oxygen Electrocatalyts under Industrial-Level Current Densities

Excellent dual-phase catalysts with spatially separated oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) sites offer great potential for high-efficiency zinc-air batteries (ZABs). However, weak interactions between interfaces and poor electron transfer severely degrade their activity and stability at industrial current densities. Here, we engineer a unique Fe–Ni bifunctional center by anchoring Ni–OH onto the pyridine N 4 atoms of the second shell of COP BTC (Fe) and further reveal the self-reconstruction mechanism of the Fe–N 4+4 /Ni–OH interfacial structure. Theories reveal that when the Fe–N bond is stretched by 1.57% and the Ni–O bond is compressed by 3.83%, the increase in the state electron density of the Fe–Ni active site reduces the ORR/OER rate-determining step energy barrier. Furthermore, the anchoring dual-phase sites stabilize the metal center and suppress metal dissolution. The self-optimized COP BTC (Fe–Ni) strain OH provides an extremely low voltage gap Δ E = 0.547 V. After 20,000 ORR cycles and 40 h of OER operation at 100 mA cm –2, it still outperforms the benchmark Pt/C-IrO 2 . Furthermore, at an industrial current density (100 mA cm –2 ), its ZABs exhibit a 4-fold higher cycling stability than the original structure, providing a new possibility for the practical application of ZABs.