Heterostructure engineering of NiCo layered double hydroxide@NiCo2S4 for solid-state rechargeable zinc-air batteries

• The NiCo-LDH@NiCo 2 S 4 is constructed via heterostructure engineering • Its electronic interaction and energy-level configuration are optimized • Its oxygen catalytic performance exceeds the pure NiCo-LDH and NiCo 2 S 4 • The corresponding zinc-air batteries deliver high power density and rechargeability Solid-state zinc-air batteries (ZABs) are considered as one of the promising next-generation energy storage devices, serving for artificial intelligence and wearable equipment. Unfortunately, they are less than satisfactory because of the unsatisfactory oxygen catalytic performance on air-electrode and the poor contact with solid-state electrolytes. Heterostructure engineering is one of the effective routes to solve the above problems. Herein, we constructed a bifunctional (oxygen reduction and evolution reactions) NiCo layered double hydroxide@NiCo 2 S 4 catalyst with well-designed heterointerfaces, which enhanced electronic interaction and optimized energy-level configuration. It delivers fast charge transfer kinetics and enhanced activity and thus achieves an excellent power density of 88.4 mW cm −2 and rechargeability with a high round-trip efficiency of 74.3% in the solid-state ZABs. This work provides deep insights into the structure-activity relationship between heterostructure catalysts and high-performance ZABs.