Nitrogen doped carbon with a high surface area was used as cathode electrode in a solid-state lithium–oxygen battery. Various techniques including the Brunauer–Emmett–Teller (BET) surface area, X-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX) were employed to evaluate the nitrogen functionality on carbon. The electrochemical properties of nitrogen doped carbon as cathode electrode in lithium–oxygen battery were studied using galvanostatic charge–discharge characteristics and electrochemical impedance spectroscopy (EIS). The lithium–oxygen cell fabricated with nitrogen doped Ketjenblack–Calgon activated carbon cathode exhibits two times higher discharge cell capacity than that of a cathode composed of only Ketjenblack–Calgon activated carbon. This work shows that the nitrogen functionality on carbon is responsible for the electro-catalytic activity of cathode and an enhancement in cell capacity of lithium–oxygen battery.