Highly Nitrogen-Doped Carbon Nanotube Nanoarrays as Self-supported Bifunctional Electrocatalysts for Rechargeable and Flexible Zinc-Air Batteries
Zhiyuan Li, Haoqi Yang, Hang Sun, Song Liang, Guolong Lu, Zhenning Liu, Shuqing Kou
Abstract
Rational design of bifunctional electrocatalysts to promote the sluggish kinetics of oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) remains a fundamental challenge for the application of zinc-air batteries (ZABs). Herein, we propose a facile and cost-effective strategy to in situ grow N-doped carbon nanotubes with encapsulated FeCo alloy nanoparticles on carbon cloths (FeCo/N-CNTs@CC) as a self-supported air cathode for rechargeable ZABs. The bamboo-like FeCo/N-CNTs@CC catalyst with high nitrogen content (10.5 atom %) exhibits excellent electrocatalytic activities, including a half-wave potential of 0.816 V for ORR and an overpotential of 1.638 V for OER at 10 mA cm–2 in alkaline medium. Impressively, the liquid-state ZAB based on the FeCo/N-CNTs@CC cathode demonstrates a remarkable power density of 132.0 mW cm–2 and a stable cycling performance over 65 h. Furthermore, the flexible all-solid-state ZAB possesses outstanding performance retention under various bending conditions. The electrocatalyst presented in this work holds great potential as a self-supported air cathode for practical applications.