FePc nanoclusters modified NiCo layered double hydroxides in parallel with Ti3C2 MXene as a highly efficient and durable bifunctional oxygen electrocatalyst for zinc-air batteries

Boosting the bifunctional oxygen activity of layered double hydroxides (LDHs) is a frontier but challenging issue for metal-air batteries. Herein, an iron phthalocyanine (FePc) nanocluster modified NiCo LDH in parallel with Ti3C2 (FePc-NiCo-LDH/Ti3C2) two-dimensional multilayer structured bifunctional oxygen catalyst is engineered by growing NiCo-LDH in parallel with Ti3C2 followed with adsorbing FePc via electrostatic interaction approach. Thanks to the abundant retained Fe-N-x active sites, the FePc-NiCo-LDH/Ti3C2 catalyzes the oxygen reduction reaction (ORR) with a half-wave potential (E-1/2) of 80 mV positive compared to Pt/C. Besides, the current density only drops 5% after 33,000 s of chronoamperometry test, confirming the robust ORR stability. On the other hand, there are electronic interactions formed between FePc nanocluster and NiCo-LDH/Ti3C2 which boosts the OER activity as demonstrated by the negatively shifted potential of 89 mV at 10 mA cm(-2) versus RuO2. The overall ORR/OER activity makes FePc-NiCo-LDH/Ti3C2 ranking top among the most active analogous samples. The Zn-air battery (ZAB) assembled with FePc-NiCo-LDH/Ti3C2 as air electrode exhibits a peak power density of 148 mW cm(-2) and can be charge-discharged continuously for 80 h. This direct engineering ORR/OER active center strategy offers a unique facile direction for the fabrication of oxygen electrode catalysts for renewable clean energy devices.

Automated summary

The bifunctional oxygen activity of layered double hydroxides (LDHs) is enhanced by modifying them with iron phthalocyanine (FePc) nanoclusters and Ti3C2, resulting in the engineered FePc-NiCo-LDH/Ti3C2 catalyst. This catalyst exhibits excellent performance in oxygen reduction reaction (ORR) and oxygen evolution reaction (OER), making it one of the most active samples among the analogues. The Zn-air battery assembled with FePc-NiCo-LDH/Ti3C2 as the air electrode shows high peak power density and long discharge time, highlighting the significance of this direct engineering strategy in renewable clean energy devices.