Long-Range Regulation of Se Doping for Oxygen Reduction of Atomically Dispersed Sb Catalysts for Ultralow-Temperature Solid-State Zn–Air Batteries

Abstract

Regulating the p-orbital valence electrons of atomically dispersed main-group metals to improve the inherent electrocatalytic activity has attracted extensive concerns. Herein, we designed and synthesized an atomically dispersed Sb–SeNC catalyst containing SbN2C2 and SeC2 structures, which have been identified by X-ray absorption spectroscopy and density functional theory (DFT) calculations. Sb–SeNC exhibits a high activity for the oxygen reduction reaction (ORR), and a Sb–SeNC-based flexible solid-state zinc–air battery (ZAB) can work efficiently at −40 °C, with a peak power density of 54.1 mW cm–2 and a rate discharge operation of about 44 h. DFT calculations further confirm the long-range regulation mechanism of the SeC2 moiety for the ORR of SbN2C2 and obtain the volcano relationship of Uonset vs the Se–N distance. When the Se–N distance is 7.4 Å, the adsorption ability of active site Sb can be regulated to an optimal state related to the RDS: *O → *OH, while the smaller Se–N distance in short-range would lead to the excessive attenuation of adsorption ability of active site and decrease of ORR activity, which therefore yields the long-range regulation effect of Se doping on the ORR activity of SbN2C2. This long-range regulation strategy may provide a promising approach to boost the catalytic activity of main-group metal catalysts to achieve its application in ultralow-temperature solid-state ZABs.