3D Porous Nb2C MXene/reduced graphene oxide aerogel coupled with NiFe alloy nanoparticles for wearable Zn–air batteries

Insufficient catalytic activity and self-restacking of 2D MXenes during catalytic processes would lead to a limited number of active sites, sluggish ionic kinetics and poor durability, extremely restricting their application in Zn–air batteries (ZABs). Herein, a facile and moderate synthetic path is reported for the synthesis of a 3D porous framework, Nb2C MXene/reduced graphene oxide aerogel coupled with NiFe alloy nanoparticles (NiFe/MG) as a cathode in wearable ZABs. The large specific surface area, abundant functional groups (O, –OH, and –F), porosity and rich channels of 3D NiFe/MG aerogel are beneficial for increasing the number of active sites, facilitating the diffusion of electrolyte and promoting transference of electrons. As a result, the NiFe/MG electrocatalyst achieves outstanding bifunctional activity delivering an indicator ΔE of 0.79 V, which is superior to the state-of-the-art commercial Pt/C + IrO2 benchmark (ΔE = 0.84 V). Specifically, the as-assembled wearable ZAB exhibits a remarkable peak power density (96.1 mW cm−2), long-term durability and outstanding mechanical stability. This study provides an ingenious strategy to promote the application of 3D MXene-based bifunctional electrocatalysts for metal–air batteries.