Controllable Constructing Janus Homologous Heterostructures of Transition Metal Alloys/Sulfides for Efficient Oxygen Electrocatalysis

Abstract

Constructing novel heterostructures is an effective way for enhancing the oxygen electrocatalytic properties of the catalysts. In this work, a class of Janus homologous heterostructures, compositing transition metal alloys with their corresponding sulfides (TM/TMS), are controllably synthesized through an ultrafast high-temperature shock (HTS) strategy. The ultrafast sintering rate and carbothermal reduction reaction lead to the formation of sulfides and partial reduction of sulfides to alloys, while the ultrafast cooling rate keeps the homologous heterostructure of TM/TMS stable. The components of TMs in the composites can be well controlled from unary to quaternary. Moreover, benefiting from the synergistic effect of the metallic sites in the interfaces, the adsorption and desorption energy barrier of the active intermediates are significantly optimized and thus leading to the enhanced oxygen catalytic performance. Impressively, the aqueous zinc-air battery (ZAB) using the binary homologous nanocomposite FeCo/(FeCo)S as air cathodes achieves impressive durability (> 470 cycles) and power density (261.8 mW cm⁻²). The as-assembled flexible ZAB can well power the wearable devices and can work for at least 300 cycles without obvious degradation. This work opens a new chemical space for designing homologous heterostructures for their application in energy storage and conversion systems.