Crosslinked Carbon Nanotube Aerogel Films Decorated with Cobalt Oxides for Flexible Rechargeable Zn–Air Batteries

Air electrodes with high catalytic activity are of great importance for rechargeable zinc–air batteries. Herein, a flexible, binder‐free composite air electrode for zinc–air batteries is reported, which utilizes a lightweight, conductive, and crosslinked aerogel film of carbon nanotubes (CNTs) functioned as a 3D catalyst‐supporting scaffold for bifunctional cobalt (II/III) oxides and as a current collector. The composite electrode shows high catalytic activities for both oxygen reduction reaction and oxygen evolution reaction, resulting from the synergistic effect of nitrogen‐doped CNTs and spinel Co 3 O 4 nanoparticles. Solid‐state Zn–air batteries assembled using such free‐standing air electrodes (without the need of additional current collectors) are bendable and show low resistances, low charge/discharge overpotentials, and a high cyclic stability.