Constructing Bridging Heterointerfaces of PtCo/Co9S8 for Enhancing Oxygen Electrocatalysis in Zn-Air Batteries

Constructing heteronanostructures is an essential approach for integrating multiple functionalities into one single entity. Here, PtCo/Co9S8 composites with bridging heterointerfaces are synthesized using an ultrafast hightemperature shock strategy. The oxygen electrocatalysis of PtCo/Co9S8 is remarkably enhanced by constructing the well-coupled Pt-Co-S interfaces in the composites, in which the Co acts as the bridging linkage. PtCo/Co9S8 composites show efficient bifunctional activities toward oxygen evolution and reduction reactions (OERs and ORRs). The OER overpotential (10 mA cm(-2)) and ORR half-wave potential reach 284 and 832 mV, respectively. The rechargeable aqueous zinc-air battery (ZAB) using PtCo/Co9S8 composites as air cathodes achieves high power density (262.5 mW cm-2) and long-term cycling life (more than 1000 cycles). Moreover, the assembled flexible solid-state ZAB can power electronic devices well. The theoretical results suggest that the catalytic sites of Co and Pt in the bridging interfaces could impressively optimize the adsorption/desorption/transformation of O* to OH*, thus lowering the ?G and facilitating the ORR process. This work provides an extremely promising strategy to develop bridging heterointerfaces for their application in energy storage and conversion systems.