Rational modulation of N, P co-doped carbon nanotubes encapsulating Co₃Fe₇ alloy as bifunctional oxygen electrocatalysts for Zinc–Air batteries

Rational design and development of non-precious metal-based electrocatalysts for bifunctional oxygen reduction/evolution reactions (ORR/OER) are essential to realize the dischargeable Zinc-air batteries (ZABs). Herein, for the first time we synthesize CoFe-alloy nanoparticles enveloped by N, P co-doped carbon nanotubes (NPMC/CoFe), through a simple route by pyrolyzing dicyandiamide complex in the presence of phytic acid. The obtained electrocatalysts possess excellent ORR (a half wave potential of 0.896 V in 0.1 M KOH) and OER (η_{10 mA cm-2} = 310 mV in 1 M KOH) performance, respectively. The liquid-state ZABs based on the NPMC/CoFe air-cathode demonstrates a high peak power density of 146.34 mW cm⁻² and excellent durability. Specifically, flexible and button-like ZABs with impressive performances are both realized, which could power light-emitting diodes. This work offers an attractive approach to develop the nonprecious metal-based ORR/OER catalysts, and modulators for the design of performance oriented electrocatalysts for wider electrochemical energy applications.