The direct effect of nitrogen content and various nitrogen species on oxygen reduction reaction (ORR) activities in non-aqueous lithium-oxygen (Li-O-2) batteries are systematically investigated. Mesoporous carbon (MC) with various nitrogen species is prepared through heat treatment of N-containing precursor under different temperature. The effect of the heat treatment temperature on the performance of carbon materials in Li-O-2 battery is investigated. The bonding state of nitrogen atoms is found to have a significant effect on the ORR activity. The ORR activity in Li-O-2 battery is proved to be dependent on the quaternary N content while the total N content in the carbon material does not play a crucial role in the ORR process. (C) 2014 Elsevier Ltd. All rights reserved.