Abstract
A dual-template strategy for facile preparation of a bifunctional oxygen electrocatalyst for high-performance rechargeable zinc–air batteries has been reported. Coupling FeNi alloys with hollow nitrogen-doped carbon frameworks results in exceptionally high electrocatalytic oxygen reduction and evolution activities. In 1 M KOH, the resulting new material exhibits a superior oxygen evolution activity with a low overpotential of 250 mV to deliver 10 mA cm−2 current density, at which the obtained oxygen reduction performance is also comparable to that of commercial Pt/C and the half-wave potential reaches as high as 0.87 V. As a result, the bifunctional oxygen electrocatalysis performance thus obtained (0.61 V, 1 M KOH) ranks among the best of non-precious oxygen electrocatalysts. Using this new catalyst as an air electrode, the as-prepared rechargeable Zn–air battery shows a high current density of 215 mA cm−2 at a voltage of 1.0 V, large peak power density (310 mW cm−2), high potential efficiency (64.7% at 10 mA cm−2) and prolonged operation durability. This approach provides a means to control the surface features, thereby tuning the catalytic properties of the material, and may open up new possibilities for the rational design and synthesis of new materials for electrochemical applications.
