p-Block anion compressed d/p band center of bifunctional oxygen electrocatalysts for durable aqueous Zn–air batteries

Abstract

Robust bifunctional electrocatalysts that accelerate the sluggish oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) are vital for rechargeable aqueous Zn–air batteries (AZABs). In this study, a three-dimensional foam-like N-doped carbon frameworks (NCFs) catalyst with abundant N CoTe 2 active sites (CoTe 2 @NCFs) was successfully constructed using the carbon dots (CDs)-assisted strategy as the efficient bifunctional ORR/OER catalyst. In situ Raman spectra were used to monitor the formation of Co-OOH, which confirmed the dynamic change in oxygen intermediates on the surface of the CoTe 2 @NCFs catalyst. Both theoretical calculations and experimental results demonstrate that the integrated Te element in the p-block results in a reduction in the difference between d/p band centers (Δ ε d-p ), which effectively enhances the rapid adsorption/desorption capability of *OOH/*OH, thereby improving the ORR/OER performance. Impressively, the CoTe 2 @NCFs catalyst shows excellent bifunctional oxygen catalytic performance (Δ E = 0.66 V). Moreover, the assembled CoTe 2 @NCFs-based rechargeable AZABs exhibit a high peak power density of 177.8 mW cm −2 , substantial specific capacity of 793.4 mAh g −1 , and excellent long-term cycling durability over 1000 cycles. The compressed d/p-band synergistic center provides novel insights into the design of bifunctional oxygen electrocatalysts for efficient energy storage and conversion devices.