NiO/Co(OH)2 Heterojunction N-Doped Carbon Nanotube Electrode for High-Stability Zinc–Air Batteries

Abstract

The development of zinc–air batteries (ZABs) requires high-performance and durable oxygen electrodes. Existing catalysts mainly optimize intrinsic catalytic activity yet suffer from poor structural stability during operation. Herein, a NiO/Co(OH)2 heterojunction is fabricated on a self-supporting N-doped carbon nanotube electrode (NiCo-CNT/SS) through electrodeposition and annealing treatment. The three-dimensional N-CNT network grown on a stainless steel substrate guarantees favorable conductivity and rapid mass transfer. Meanwhile, the formed NiO/Co(OH)2 heterostructure regulates the local electronic configuration to improve intrinsic oxygen evolution reaction activity. The obtained electrode achieves a low OER overpotential of 258 mV at 10 mA cm–2. Assembled as a binder-free air cathode, the aqueous ZAB achieves a peak power density of 152.3 mW cm–2 and maintains stable operation for more than 480 h at 5 mA cm–2, showing superior performance compared with commercial catalysts. This work develops stable electrode materials and offers a feasible strategy for constructing robust electrocatalysts toward advanced metal–air energy devices.