Outstanding platinum group metal-free bifunctional catalysts for rechargeable zinc-air batteries

Developing highly active and durable catalysts for zinc-air batteries (ZAB) is critical for energy conversion and storage. Herein, we prepared Fe-N-C catalysts at a kilogram scale by the commercial VariPoreTM method and the effect of synthesis conditions on the catalyst performance at ZAB air electrode was investigated. The results show the PA-450-HT exhibits excellent electrocatalytic activity toward oxygen reduction reaction (ORR) and it is the most suitable catalyst for primary ZAB with the galvanostatic polarization discharge peak power density of 149 mW cm-2, outperforming commercial Pt-Ru/C catalysts. Additionally, the NCB-600-HT catalyst displays the half-wave potential of 0.87 V vs. RHE for ORR and Delta E value of 0.81 V (indicating outstanding ORR and OER reversibility) and exhibits excellent charge-discharge cycling durability similar to NCB-550-LT around 160 h for the secondary ZAB. This work reports outstanding bifunctional Fe-N-C catalysts for rechargeable ZAB at mass production for the first time.

Automated summary

In this study, Fe-N-C catalysts were prepared at a kilogram scale using the commercial VariPoreTM method, and the effect of synthesis conditions on the catalyst performance at ZAB air electrode was investigated. The results showed that the PA-450-HT catalyst exhibited excellent electrocatalytic activity for the oxygen reduction reaction (ORR) and was the most suitable catalyst for primary ZAB, with a galvanostatic polarization discharge peak power density of 149 mW cm-2, outperforming commercial Pt-Ru/C catalysts. Additionally, the NCB-600-HT catalyst displayed outstanding ORR and OER reversibility, with a half-wave potential of 0.87 V vs. RHE and a Delta E value of 0.81 V, and exhibited excellent charge-discharge cycling durability similar to NCB-550-LT for the secondary ZAB. This study reported for the first time the mass production of outstanding bifunctional Fe-N-C catalysts for rechargeable ZAB.