Confined SnSb Nanoalloys in N-Doped Carbon: A High-Performance Oxygen Reduction Electrocatalyst for Zinc-Air Battery

Amidst depleting traditional energy resources and pressing demands for sustainable technologies, developing efficient, low-cost and pH-universal oxygen reduction reaction (ORR) catalysts is crucial for advancing fuel cells and metal-air battery. Currently, Pt-based materials represent the most efficient electrocatalysts for ORR, yet their commercial deployment is constrained by high costs and moderate stability. In this work, we successfully encapsulated SnSb alloy nanoparticles in N-doped porous carbon using 4,5-dicyano-2-aminoimidazole as a dual-functional molecular precursor with sacrificial MgO templates, achieving nanolevel metal dispersion and alloy-carbon coupling. The catalyst, incorporating N-doped porous carbon with a high specific surface area and nanosized SnSb alloy as active sites, exhibits outstanding ORR activity with half-wave potentials (<i>E</i>_1/2) of 0.87 V in 0.1 M KOH, 0.76 V in 0.1 M PBS, and 0.67 V in 0.5 M H₂SO₄, which DFT calculations attribute to favorable d-band modulation and optimized intermediate adsorption from Sn-Sb synergy. In zinc-air battery, the catalyst delivers a peak power density of 169 mW·cm^-2 and an energy density of 848.8 Wh·kg_Zn^-1 at 10 mA·cm^-2, markedly higher than Pt/C benchmarks, confirming its significant potential for practical energy-conversion devices.