Iron carbide decorated carbon nanosphere- sheet hybrid based rechargeable high-capacity non-aqueous Li–O2 batteries

High energy density carbon-neutral electrochemical systems are highly sought after for next-generation energy technologies, and lithium-oxygen (Li–O 2 ) battery occupies a unique position in them. Here, we report the development of a high capacity (9000 mAh g −1 ), long-term cyclability (>60 cycles), low-cost (iron and carbon) catalyst based non-aqueous Li–O 2 battery and unravel the role of the catalyst's porosity and structure in the battery performance. A scalable catalyst, named FeN x C y (S/S), is shown as the bifunctional catalyst at the cathode of the cell, where FeN x C y (S/S) has a unique structure constituted by nitrogen doped iron carbide nanoparticles decorated graphitic carbon spheres connected via graphitic sheets. The mechanism of the growth of discharged product in correlation with the high surface area and meso-porosity in FeN x C y (S/S) are studied using in situ Raman and ex situ XRD studies. The study shows the potential of Li–O 2 batteries as low-cost energy systems having high energy density (2920 Wh kg Li2O2 −1 ) and power density (18 mW cm −2 ) values that are close to their theoretical limits.