Mono‐Doped Carbon Nanofiber Aerogel as a High‐Performance Electrode Material for Rechargeable Zinc‐Air Batteries

Abstract

AbstractNitrogen‐doped porous carbon (NPC) materials have attracted increased attention for zinc‐air battery (ZAB) applications because of their comparable electrocatalytic activity to precious metals. However, few metal‐free NPC catalysts exhibit an oxygen reduction reaction performance better than Pt catalysts, together with high oxygen evolution reaction catalytic activity. Herein, an efficient oxygen electrocatalyst based on highly integrated carbon nanofiber (CNF) and NPC aerogels, with CNF as the core and NPC as the shell, is demonstrated. The NPC@CNF aerogels are prepared through a large‐scale, direct pyrolysis of metal‐organic frameworks and bacterial cellulose hybrids. This mono‐doped carbon material with nitrogen heteroatoms displays outstanding bifunctional performance compared to the individual counterparts, which demonstrates the effectiveness of morphological and structural engineering. Density functional theory calculations reveal that the active sites with the participation of multi‐electrons weaken the O−O bond and facilitate the four‐electron oxygen reduction in the dissociation pathway. The ZAB based on the NPC@CNF air electrode exhibits a peak density of 96 mW cm−2 and a stable charge–discharge durability of over 420 cycles with an overpotential increase of only 0.10 V, indicating that the mono‐doped NPC@CNF performs as one of the best bifunctional catalysts among those recently reported metal‐based and metal‐free catalysts.