Controllable Construction of Bifunctional Co<i><sub>x</sub></i>P@N,P‐Doped Carbon Electrocatalysts for Rechargeable Zinc–Air Batteries
Qing Shi, Qiao Liu, Yapeng Zheng, Yaqian Dong, Lin Wang, Hantao Liu, Weiyou Yang
Abstract
The exploration of cheap, efficient, and durable bifunctional electrocatalysts for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) is highly desired to push forward the commercialization of rechargeable metal–air batteries. Here, bifunctional ORR/OER electrocatalysts based on Co x P (0 < x < 2, i.e., Co 2 P, Co 2 P/CoP mixture, and CoP) nanoparticles (NPs) anchored on N,P‐doped carbon framework (Co x P@NPC) are developed via one‐step carbonization of the mixture of as‐synthesized ZIF‐67 and melamine–phytic acid supermolecular aggregate (MPSA). The stoichiometric ratio of resultant Co x P NPs can be rationally designed by adjusting the introduced ratio of ZIF‐67 to MPSA, enabling their fabrication in a controlled manner. It is found that the as‐synthesized Co 2 P@NPC exhibits the best bifunctional ORR/OER activity among the Co x P@NPC analogues, with a reversible oxygen electrode index (Δ E = E j10 − E 1/2 ) down to ~0.75 V. The constructed Zn–air battery based on Co 2 P@NPC delivers a peak power density of 157 mW cm −2 and an excellent charge‐discharge stability with negligible voltage decay for 140 h at 10 mA cm −2 , superior to those based on Pt/C+RuO 2 and most Co x P‐based electrodes ever reported.