In situ growth of N-doped bamboo-like carbon nanotubes embedded with FeNi nanoparticles on carbon cloth as self-standing cathodes for efficient rechargeable zinc–air batteries†

Abstract

In situ growth of N-doped bamboo-like carbon nanotubes embedded with FeNi nanoparticles on carbon cloth (FeNi@NBCNTs/CC) has been reported, along with the demonstration of the direct application of FeNi@NBCNTs/CC as self-standing bifunctional air cathodes in rechargeable zinc–air batteries (RZABs). The resulting FeNi@NBCNTs/CC, with 3D integrated conductive frameworks, large surface area, hierarchically porous architecture and embedded FeNi nanoparticles, provided sufficient accessible reaction sites and an optimal charge/mass transfer environment. Thus, the FeNi@NBCNTs/CC exhibited excellent electrocatalytic performance toward the oxygen reduction reaction (ORR) with a positive half-wave potential of 0.90 V and toward the oxygen reduction reaction (OER) with a low potential of 1.52 V at 10 mA cm⁻², outperforming commercial Pt/C and Ru/C catalysts, respectively. Impressively, they served as self-standing air cathodes for liquid and flexible quasi-solid-state RZABs, demonstrating outstanding battery performance with high energy density, robust durability with a low rate of energy loss and favorable flexibility. This work provides a useful strategy for fabricating low-cost and efficient electrodes without the use of polymeric binders and noble metals for metal–air batteries and other related fields.