Rational design of multifunctional electrocatalyst: An approach towards efficient overall water splitting and rechargeable flexible solid-state zinc–air battery

Constructing an electrocatalyst with highly durable active and cost-effective core-shell with a porous carbon nanosheet for the development of high efficiency energy conversion and storage devices. Herein, we developed core-shell nickel-iron oxide on a highly porous N-doped carbon nanosheet (CS-NFO@PNC) via a facile solvothermal calcination route. The optimized CS-NFO@PNC-700 showed remarkable electrocatalytic activity towards ORR (0.85 V vs RHE), OER ƞ₁₀ = 217 mV, and HER ƞ₁₀ = 200 mV with excellent durability towards the corresponding half-cell reactions. Further, we investigated the ORR, OER, and HER mechanistic pathways of the electrocatalyst using the density functional theory. Finally, we fabricated a rechargeable liquid electrolyte-based zinc–air battery with CS-NFO@PNC-700 as the cathode which displayed an improved power density of 130 mW cm⁻² at 217 mA cm⁻² with excellent durability of 180 h. The rechargeable flexible quasi-solid-state zinc–air battery with CS-NFO@PNC-700 air cathode, which exhibited excellent long term durability over 40 h at 5 mA cm⁻².