Electron Modulation and Morphology Engineering Jointly Accelerate Oxygen Reaction to Enhance Zn-Air Battery Performance

Combining morphological control engineering and diatomic coupling strategies, heteronuclear Fe-Co bimetals are efficiently intercalated into nitrogen-doped carbon materials with star-like to simultaneously accelerate oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). The half-wave potential and kinetic current density of the ORR driven by FeCoNC/SL surpass the commercial Pt/C catalyst. The overpotential of OER is as low as 316 mV (eta(10)), and the mass activity is at least 3.2 and 9.4 times that of mononuclear CoNC/SL and FeNC/SL, respectively. The power density and specific capacity of the Zn-air battery with FeCoNC/SL as air cathode are as high as 224.8 mW cm(-2) and 803 mAh g(-1), respectively. Morphologically, FeCoNC/SL endows more reactive sites and accelerates the process of oxygen reaction. Density functional theory reveals the active site of the heteronuclear diatomic, and the formation of FeCoN5C configuration can effectively tune the d-band center and electronic structure. The redistribution of electrons provides conditions for fast electron exchange, and the change of the center of the d-band avoids the strong adsorption of intermediate species to simultaneously take into account both ORR and OER and thus achieve high-performance Zn-air batteries.

Automated summary

By combining morphological control engineering and diatomic coupling strategies, heteronuclear Fe-Co bimetals can be efficiently intercalated into nitrogen-doped carbon materials, forming a star-like structure, which can simultaneously accelerate the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). The FeCoNC/SL catalyst driven ORR exhibits higher half-wave potential and kinetic current density than the commercial Pt/C catalyst. The OER overpotential is as low as 316 mV (eta(10)), and the mass activity is at least 3.2 and 9.4 times that of mononuclear CoNC/SL and FeNC/SL, respectively. The Zn-air battery with FeCoNC/SL as the air cathode shows a high power density of 224.8 mW cm(-2) and a specific capacity of 803 mAh g(-1).