NiFe nanoparticles embedded N-doped carbon nanotubes as high-efficient electrocatalysts for wearable solid-state Zn-air batteries

Wearable and rechargeable Zn-air batteries (ZABs) hold great potential application in flexible electronic devices, and light-weight power sources for their high energy density and good safety. However, the practical application of ZABs is hindered by their low power density and poor rechargeability, which arises from the sluggish kinetics of oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) on air cathode. Herein, a high-power, wearable ZAB with impressive electrochemical performances is achieved based on a new NiFe nanoparticles embedded N-doped carbon nanotubes (NiFe/N-CNT) as bifunctional electrocatalyst. The in-situ Raman and oxygen adsorption and DFT calculations reveal that our designed NiFe/N-CNT catalyst can remarkably promote the oxygen adsorption in ORR and OH− adsorption in OER, which enable this NiFe/N-CNT to own superior electrocatalytic activity toward both OER and ORR. The as-fabricated wearable ZAB with the NiFe/N-CNT as air cathode exhibits an ultrahigh open-circuit potential (Voc) of 1.41 V and a remarkable high peak power density of 105.4 mW cm−2, Furthermore, it also obtains a small charge-discharge voltage gap of 0.61 V and superior durability for 800 min. This research provides a new design pathway for the electrocatalysts for high-performance rechargeable and wearable metal-air batteries.