Core-Shell Catalysts with Superhydrophobicity for Enhanced Oxygen Reduction Kinetics in Zinc-Air Batteries.

Zinc-air batteries (ZABs) operating in gas-solid-liquid three-phase systems suffer from sluggish reaction kinetics and low power output, which severely hinder their commercialization. To address these challenges, an integrated strategy is proposed combining core-shell heterophase catalytic species with superhydrophobic properties. The H─CoFe─CNT catalyst, featuring carbon nanotube-grown hollow cubic carbon cages, incorporates metal carbide@metal core-shell heterophase catalytic species and exhibits superhydrophobicity. The metal carbide@metal core-shell structure modulates the electronic state of catalytic sites, reduces the oxygen reduction reaction (ORR) energy barrier, and enhances catalytic activity. Meanwhile, the superhydrophobic property of the catalyst creates an abundant triple-phase reaction interface, promotes oxygen accumulation at the air cathode, thereby improving ORR kinetics and boosting the power density of ZABs. The as-prepared H─CoFe─CNT catalyst demonstrates exceptional oxygen electrocatalytic activity, achieving a high ORR half-wave potential of 0.909 V and a low oxygen evolution reaction (OER) overpotential of 307 mV. Liquid ZABs assembled with this catalyst exhibit a peak power density of 255 mW cm, and outstanding durability. Moreover, quasi-solid-state ZABs deliver an ultrahigh peak power density of 610 mW cm, indicating promising practical applicability. This work opens a new avenue for developing high-power-density ZABs through the synergistic integration of core-shell heterophase catalytic species and superhydrophobic engineering.