Efficient Bifunctional NiFe-LDH@Co9S8 Nanoflower Electrocatalysts Anchored with Pt Nanocrystal for Flexible Quasi-solid Rechargeable Zinc Air Battery

Efficient and affordable electrocatalysts are a crucial part of rechargeable zinc air batteries (ZAB) to address the problems caused by the sluggish activity of the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) on the cathode. Anchoring noble metals on transition-metal-based substances is a promising strategy to reinforce electrochemical activity and reduce the cost. Herein, we have developed a subsequent spontaneous-redox strategy to load Pt nanoparticles with 3.75% containing NiFe-LDH nanoflakes to boost the ORR activity. After that, NiFe-LDH@ Co9S8 is constructed as a rational design for bifunction catalysis. In the ORR process, the half-wave potential of the obtained catalyst, Pt-anchored NiFe-LDH@Co9S8, is 0.83 V vs RHE, showing better catalytic activity than Pt/C. In the OER process, the obtained catalyst exhibits a low overpotential of 280 mV, which is superior to that of RuO2. Notably, aqueous ZAB and quasi-solid-state ZAB achieve peak power densities of 164.3 and 78.4 mW cm–2, respectively. Furthermore, quasi-solid-state ZAB exhibits a long cycle lifespan for 240 cycles in 80 h, and a remarkable stability after bending for 50 cycles. This work paves the way for the design of the NiFe-LDH nanostructure by vacancy engineering.