Boosting electrocatalytic activity with the formation of abundant heterointerfaces and N, S dual-doped carbon nanotube for rechargeable Zn-air battery

Herein, a facile synthetic strategy is proposed to fabricate high-performance electrocatalysts for rechargeable Zn-air batteries (ZABs). Heterostructured NiCo/NiCo2S4 nanoparticles encapsulated in N-, S- co-doped CNT (NiCo/NiCo2S4@NSCNT) are synthesized via co-precipitation, thermal carbonization, and partial sulfidation processes. The strongly coupled NiCo/NiCo2S4 heterostructure can improve the redox property and charge transfer ability. Also, the CNTs with abundant foreign dopants provide high electrical conductivity and abundant defect sites for both the oxygen evolution reaction (OER) and oxygen reduction reaction (ORR). The prepared NiCo/NiCo2S4@NSCNT electrocatalyst exhibits a low overpotential of 349 mV at a current density of 10 mA cm−2 and a half-wave potential of 0.865 V for the OER and ORR, respectively. Moreover, the ZAB assembled using as-prepared NiCo/NiCo2S4@NSCNT can provide superior specific capacity (756.16 mA h gZn−1), peak power density (155.82 mW cm−2), and long-term cyclability compared to those of the precious metal-based electrocatalyst (Pt/C + RuO2).