Li-O-2 batteries with super-high theoretical energy density are attracting extensive attention. However, the sluggish oxygen reduction/ evolution reaction, the huge volume change from O-2/Li2O2 conversion and the undesired electrolyte decomposition in cathode limit their performance. Herein we show design and synthesis of RuO2-coated ordered mesoporous carbon nanofiber arrays by using a natural crab shell template as a catalyst for Li-O-2 battery, exhibiting several advantage features. First, the ordered mesopores in nanofibers facilitate electrolyte penetration and electron/ion transfer. In addition, the macrosized voids between the nanofibers provide efficient buffer space for O-2/Li2O2 accommodation and improve O-2 diffusion. Furthermore, the uniform RuO2-coating layer alleviates undesired electrolyte decomposition and enhances the surface electronic conductivity. As a result, the battery displays high performance, including high capacity (20600 mAh g(-1) at a current density of 100 mA g(-1)), high rate (9750 mAh g(-1) at a current density of 1000 mA g(-1)) and long-life (300 cycles at a fixed capacity of 1000 mAh g(-1)). (C) 2014 Elsevier B.V. All rights reserved.