Fe/Fe3C Embedded in N-Doped Worm-like Porous Carbon for High-Rate Catalysis in Rechargeable Zinc-Air Batteries.

Designing low-cost preparation of high-activity electrocatalysts with excellent stability is the route one must take to fully realize large-scale application implementation of zinc-air batteries. 3D nitrogen-doped nanocarbons with transition metals or their derivatives encapsulated in show promising potential in the field of non-precious metal oxygen electrocatalysis. Herein, we report a simple, economical, and large-scale production method to construct worm-like porous nitrogen-doped carbon with in situ-grown carbon nanotubes and uniformly embedded Fe/Fe3C nanoparticles. It not only has high conductivity owing to the nitrogen-doped nature but also has ample active sites and electrolyte diffusion channels benefitting from the uniformly distributed heterostructural Fe/Fe3C nanoparticles and discrete hierarchically porous structures. When used as catalyst materials for a zinc-air battery, an energy density of 719.1 Wh kg-1 and a peak power density of 101.3 mW cm-2 at a 50 mA cm-2 discharge current density is achieved. Additionally, throughout charging and discharging for 200 cycles at a current density of 20 mA cm-2, the charge/discharge voltage gap is nearly constant.