A Stable Rechargeable Aqueous Zn-Air Battery Enabled by Heterogeneous MoS2 Cathode Catalysts

Aqueous rechargeable zinc (Zn)-air batteries have recently attracted extensive research interest due to their low cost, environmental benignity, safety, and high energy density. However, the sluggish kinetics of oxygen (O-2) evolution reaction (OER) and the oxygen reduction reaction (ORR) of cathode catalysts in the batteries result in the high over-potential that impedes the practical application of Zn-air batteries. Here, we report a stable rechargeable aqueous Zn-air battery by use of a heterogeneous two-dimensional molybdenum sulfide (2D MoS2) cathode catalyst that consists of a heterogeneous interface and defects-embedded active edge sites. Compared to commercial Pt/C-RuO2, the low cost MoS2 cathode catalyst shows decent oxygen evolution and acceptable oxygen reduction catalytic activity. The assembled aqueous Zn-air battery using hybrid MoS2 catalysts demonstrates a specific capacity of 330 mAh g(-1) and a durability of 500 cycles (similar to 180 h) at 0.5 mA cm(-2). In particular, the hybrid MoS2 catalysts outperform commercial Pt/C in the practically meaningful high-current region (>5 mA cm(-2)). This work paves the way for research on improving the performance of aqueous Zn-air batteries by constructing their own heterogeneous surfaces or interfaces instead of constructing bifunctional catalysts by compounding other materials.

Automated summary

This study reports a stable rechargeable aqueous zinc-air battery using a heterogeneous two-dimensional molybdenum sulfide cathode catalyst. The catalyst shows decent oxygen evolution and acceptable oxygen reduction catalytic activity compared to commercial ones.