Dual Heteroatom‐Doped Carbon Nanofoam‐Wrapped Iron Monosulfide Nanoparticles: An Efficient Cathode Catalyst for Li–O2 Batteries

Abstract Cost‐effective dual heteroatom‐doped 3D carbon nanofoam‐wrapped FeS nanoparticles (NPs), FeS‐C, act as efficient bifunctional catalysts for Li–O 2 batteries. This cathode exhibits a maximum deep discharge capacity of 14 777.5 mA h g −1 with a 98.1 % columbic efficiency at 0.1 mA cm −2 . The controlled capacity (500 mA h g −1 ) test of this cathode delivers a minimum polarization gap of 0.73 V at 0.1 mA cm −2 and is sustained for 100 cycles with an energy efficiency of approximately 64 % (1st cycle) and 52 % (100th cycle) at 0.3 mA cm −2 , under the potential window of 2.0–4.5 V. X‐ray photoelectron spectroscopy reveals the substantial reversible formation and complete decomposition of Li 2 O 2 . The excellent recharging ability, high rate performance, and cycle stability of this catalyst is attributed to the synergistic effect of FeS catalytic behavior and textural properties of heteroatom‐doped carbon nanostructures.