Designing Hydrophobic Micro‐Three‐Phase Reaction Interfaces to Enhance the ORR Kinetics Toward Zinc‐Air Battery

Taking advantage of the constructed micro-three-phase interfaces (MTPI), significantly enhancing the effective active sites of ORR and expediting the mass transfer process, the Zn−air batteries (ZABs) achieve a lower overpotential (0.77 V @ 2 mA cm⁻²) and a longer service life (>1000 h). Critical insights for designing high-current and long-duration ZABs are provided by this work.

Abstract

Zinc−air batteries (ZABs) are considered as a promising option for energy storage systems and the consumer electronic market. The sluggish kinetics of oxygen reduction/evolution reactions at cathodes result in issues such as low power density and unsatisfactory cyclic life. Herein, a superiorly simple strategy of hydrophobicity engineering is used to regulate the rich micro-three-phase interfaces (MTPI) of the cathode by adopting hydrophobic ionic liquid coated on N-doped hollow carbon spheres. According to the results of ab initial molecular dynamics simulation and finite element method, the spatial distance between the catalysts and electrolytes can be effectively expanded by the generated hydrophobic micro-environment, which is beneficial to creating cavities at the boundaries of the three-phase interfaces of the electrochemical reaction, further improving the oxygen concentration around the catalytic active sites and improving the sufficient utilization of the catalytic active sites. Accordingly, the as-assembled ZABs exhibit an excellent rate performance of 0.94 V (@ 150 mA cm⁻²), lower galvanostatic charge–discharge voltage gap of 0.77 V (2 mA cm⁻²) with extremely long cyclic stability over 1000 h, and a maximum power density of 193 mW cm⁻². The obtained beneficial results provide a promising strategy for designing high-performance ZABs and promoting its industrial application.