CoSb3 alloy nanoparticles wrapped with N-doped carbon layers as a highly active bifunctional electrocatalyst for zinc-air batteries

Rational design and successful synthesis of highly efficient, long-term stable and low-cost bifunctional electro-catalysts are vital for commercialized application of rechargeable zinc-air batteries. Herein, a series of composite catalysts of different contents of CoSb3 alloy nanoparticles wrapped with N-doped carbon layers (CoSb3@NCL) have been synthesized by a simple one-step pyrolytic process. The optimized catalyst (CoSb3@NCL-30) exhibits excellent catalytic activities for both the ORR and OER in alkaline medium, which can be competitive with the Pt/ C catalyst (20%). More importantly, a real rechargeable zinc-air battery with the CoSb3@NCL-30 catalyst serving as an air cathode exhibits outstanding electrochemical properties and excellent cycling stability (the overall increment of the voltage gap was only 0.1 V after 60 hours), making it possible to replace expensive noble metal-based catalysts for actual application in rechargeable zinc-air batteries.