In situ Construction of Multistage Core-Shell Nanostructure as Bifunctional Catalyst for Ultrastable Zinc-Air Batteries.

ABSTRACT

Many efforts have been devoted to obtaining excellent cathode catalysts for Zinc air batteries (ZABs), but the inevitable use of binder will damage the catalytic activity and weaken long-term stability, inefficient mass transfer of oxygen is also chargable for the limited activity. Herein, in situ grown hydrogen substituted graphdiyne (HGDY) on carbon paper has been prepared and used as cathode catalyst layer in ZABs. Multiple catalytic sites are firmly combined and end with the boosted bifunctional catalytic activity of oxygen reduction and oxygen evolution. Moreover, the specific surface area, sufficient active sites, multilevel pore nanostructure and robust conductivity are fully exposed to establish efficient catalytic interface and skeleton. Cu/Co nanoparticles are uniformly distributed and warped by HGDY network, which can stably exist during the catalytic process. As a result, a current density of 18.75 mA cm-2 and a Tafel slope of 61.06 mV dec-1 for oxygen reduction and a ultralong operation for more than 2300 h in aqueous ZAB have been achieved, which is beyond many reported bifunctional catalysts in ZAB system.