Atomic Synergy of Vacancy‐Engineered Layered Double Hydroxide/Heteroatom‐Doped Carbon Quantum Dots for Bifunctional Oxygen Electrocatalysis in Zn–Air Batteries

ABSTRACT Low conductivity and poor oxygen reduction reaction (ORR) catalytic activity limit the bifunctional catalytic performance of layered double hydroxide (LDH) in zinc–air batteries. In this work, an efficient bifunctional electrocatalyst was prepared by loading nitrogen and phosphorus co‐doped carbon quantum dots (NPCQDs) onto a cationic‐vacancy‐containing NiFe‐LDH substrate (NPCQDs@NiFe v ‐LDH). The catalyst exhibits an overpotential of 280 mV for the OER at a current density of 10 mA cm −2 and a half‐wave potential of 0.82 V for the ORR. Benefiting from the cationic vacancy engineering and interfacial electronic coupling of NPCQDs@NiFe v ‐LDH, the electron transfer from NiFe‐LDH to NPCQDs was promoted, generating more higher‐valence Ni 3+ states and optimizing OER intermediates adsorption kinetics. Furthermore, N, P heteroatoms doping in CQDs resulted in the modulated electronic structure, and the formed heterostructure with NiFe v ‐LDH increased the specific surface area, thereby promoting mass transfer and exposure of active sites, thus improving the bifunctional catalytic performance. The Zn–air battery (ZAB) assembled using this catalyst achieves a high‐power density of 124.6 mW cm −2 , a large energy density of 799.8 mAh g Zn −1 , and remarkable long cycle stability with high round‐trip efficiency. Similarly, flexible ZABs demonstrate high power density and outstanding cycling stability. This work provides a novel strategy to enhance the bifunctional catalytic reactivity of electrocatalysts for ZAB.