CoNi Alloy@N-Doped Carbon Nanotube Mott-Schottky Heterojunction for Efficient ORR/OER in Zinc-Air Batteries

Enhancing electron transfer, mass diffusion, and structural stability through interface regulation and nanostructure design is critical for enhancing the catalytic performance of carbon-based materials. Herein, derived from the 2D CoNi-ZIF nanosheets supported on carbon cloth (CC), a 1D/2D self-supported Mott-Schottky-type heterogeneous electrocatalyst (CoNi@NCNT/CC), composed of CoNi alloy encapsulated in a 1D N-doped carbon nanotube (NCNT), was fabricated via an in situ growth strategy. Theoretical calculations prove that the rectifying contact between CoNi and NCNT is beneficial for regulating the electronic states, resulting in spontaneous electron transfer at the Mott-Schottky interface and optimizing the energy barriers associated with the elemental steps of the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) . Moreover, the interconnected structure formed by the NCNT can offer highly accessible channels for active sites, dramatically promoting mass diffusion in the electrocatalytic process. As expected, this electrocatalyst delivers a half-wave potential of 0.860 V and an overpotential of 323 mV at 10 mA cm^-2. With excellent bifunctional activity, CoNi@NCNT/CC exhibits promising peak power density and long-term stability when applied in liquid (146 mW cm^-2, 510 h) and solid-state (62 mW cm^-2, 58 h) zinc-air batteries (ZABs). This work enhances both electron and mass transfer capabilities in Mott-Schottky catalysts. It lays the foundation for the design of bifunctional electrocatalysts with rapid kinetics for next-generation ZABs.