Interfacial electric field engineering in Ni-ZrC heterostructures for high-efficiency zinc-air batteries

Developing efficient non-precious oxygen reduction reaction (ORR) catalysts remains a critical challenge. Herein, a direct current (DC) arc plasma strategy was demonstrated to construct nitrogen-doped carbon-coated Ni-ZrC heterostructured nanoparticles ((Ni/ZrC)@NC NPs) with precisely tuned interfacial built-in electric fields (BIEFs). Theoretical studies reveal that the significant work function difference (Δ Φ ) drives an asymmetric charge redistribution at the Ni-ZrC heterointerface, shifting d-band centers to optimize the adsorption energy of oxygen intermediates and to reduce reaction energy barriers. In situ optical emission spectroscopy (OES) captures the dynamic plasma evolution (electron temperature ( T e ) at local thermal equilibrium (LTE): 10,330.9 K), elucidating real-time atomic/ionic flux variations and formation mechanism of the core-shell structure and heterostructure. The synergistic Ni-ZrC core and N-doped carbon shell cooperatively enhance charge transfer kinetics and expose abundant active sites. The resulting catalyst achieves exceptional ORR activity with a half-wave potential ( E 1/2 ) of 0.82 V, surpassing Pt/C (0.80 V), alongside superior methanol tolerance and 4e − selectivity. When deployed in both liquid and all-solid-state flexible zinc-air batteries (FZABs), the catalyst delivers superior metrics: peak power densities of 251.63 mW cm −2 (liquid) and 184.22 mW cm −2 (flexible), and stable operation for a long time. This work establishes a paradigm for manipulating interfacial electronic structures via BIEFs engineering, providing a versatile platform for high-performance energy conversion technologies.