Heterointerface promoted trifunctional electrocatalysts for all temperature high-performance rechargeable Zn-air batteries

The rational design of wide-temperature operating Zn-air batteries is crucial for their practical applications. However, the fundamental challenges remain; the limitation of the sluggish oxygen redox kinetics, insufficient active sites, and poor efficiency/cycle lifespan. Here we present heterointerface-promoted sulfur-deficient cobalt-tin-sulfur (CoS 1− δ /SnS 2− δ ) trifunctional electrocatalysts by a facile solvothermal solution-phase approach. The CoS 1− δ /SnS 2− δ displays superb trifunctional activities, precisely a record-level oxygen bifunctional activity of 0.57 V ( E 1/2 = 0.90 V and E j =10 = 1.47 V) and a hydrogen evolution overpotential (41 mV), outperforming those of Pt/C and RuO 2 . Theoretical calculations reveal the modulation of the electronic structures and d-band centers that endorse fast electron/proton transport for the hetero-interface and avoid the strong adsorption of intermediate species. The alkaline Zn-air batteries with CoS 1− δ /SnS 2− δ manifest record-high power density of 249 mW cm −2 and long-cycle life for >1000 cycles under harsh operations of 20 mA cm −2 , surpassing those of Pt/C + RuO 2 and previous state-of-the-art catalysts. Furthermore, the solid-state flexible Zn-air battery also displays remarkable performance with an energy density of 1077 Wh kg −1 , >690 cycles for 50 mA cm −2 , and a wide operating temperature from +80 to −40 °C with 85% capacity retention, which provides insights for practical Zn-air batteries. Flexible solid-state Zn-air batteries with CoS 1− δ /SnS 2− δ and CBCs demonstrate a high energy density of 256 Wh kg cell −1 including all active and inactive components, high operating rates of 50 to 100 mA cm −2 , and a temperature range of +80 to −40 °C.