Synergetic of Built-In Electric Field and Sulfur Defects in Co@Co9S8 Mott-Schottky To Achieve High-Efficiency Zinc-Air Battery Performance

The slow kinetics of the bifunctional (OER/ORR) oxygenelectrocatalystis the bottleneck problem restricting the performance of zinc-airbatteries (ZABs). The design and synthesis of an efficient and stableelectrocatalyst at the air cathode to improve the performance of ZABsis of great significance for the development of sustainable energyconversion devices. Herein, we have developed a sulfur vacancy-richMott-Schottky catalyst (Co@Co9S8-NCNT),which shows superior ORR/OER bifunctional electrochemical activityand stability. Specifically, the OER overpotential is only 210 mVat 10 mA cm(-2), and the half-wave potential (E (1/2)) of ORR is up to 0.88 V. Furthermore, aZAB has been assembled using the Co@Co9S8-NCNT,which delivers a high power density (196.7 mW cm(-2)) and an open-circuit voltage (1.501 V), showing excellent batteryperformance. Density functional theory calculations demonstrate thatthe Co@Co9S8 Mott-Schottky heterojunctionand S vacancy defects are beneficial to elevate the d-band centralenergy level to the Fermi level, significantly enhancing the adsorption/desorptioncapacity of oxygen-containing intermediates, thereby effectively improvingthe OER activity. Moreover, the N-doped carbon nanotubes can promotethe continuous electron transfer between the metal and semiconductorinterface. This work proposes a valid method for the constructionand structural regulation of Mott-Schottky catalysts and offersnew insights into the development of catalytic materials for energyconversion equipment.

Automated summary

Researchers have developed a sulfur vacancy-rich Mott-Schottky catalyst (Co@Co9S8-NCNT) with superior ORR/OER bifunctional electrochemical activity and stability at the air cathode. This catalyst exhibits excellent battery performance in zinc-air batteries, providing a valid method for the construction and structural regulation of Mott-Schottky catalysts.