Reactive template-induced core-shell FeCo@C microspheres as multifunctional electrocatalysts for rechargeable zinc-air batteries.

Sluggish kinetics and thermodynamic unfavorability restrict electrocatalysis for energy storage and conversion reactions such as oxygen reduction/evolution and hydrogen evolution reactions. Herein, we report the synthesis and electrochemical performance of novel core-shell nanoparticles@porous carbon microspheres. A unique core-shell architecture of dual-phase FeCo-based nanoparticles@heteroatom-doped carbon microspheres (FeCo@C MS) has been prepared via a two-step carbonization process from a reactive multifunctional core-double shell template. With the advantages of heterogeneous composition and architectural structure, the obtained FeCo@C MS exhibits excellent performances for the electrochemical oxygen reduction reaction (ORR) and hydrogen evolution reaction (HER), which are comparable to those of commercial Pt/C catalyst. As an excellent cathode catalyst of the Zn-air battery (ZAB), FeCo@C MS exhibits high discharge voltage of 1.27 V, high specific capacity of 503 mA h gZn-1, an energy density of 639 W h kgZn-1, and better cycling durability than the battery having a mixture of 20 wt% Pt/C and RuO2. This approach provides a new way to design structures with controlled morphology and excellent multifunctional electrocatalytic activity.