Binder-free, graphitic, hierarchically porous carbon nanofiber (CNF) electrodes with in-situ encapsulated Co-Ni catalysts are synthesized with electrospinning as an efficient oxygen electrode for Li-O-2 batteries (LOBs). The inherently interconnected, graphitic network makes it unnecessary to include binders and carbon additives, therefore eliminating the possible side reactions from binder and facilitating the ion and electrical transport in the electrodes. The in-situ encapsulation of Co-Ni nanoparticles facilitates uniform dispersion of catalysts and prevents the catalyst aggregation after cycles. The resulting Co-Ni/CNF composite electrodes deliver competitive electrochemical performance of 8635 mAh g(c)(-1) at a current density of 200 mA g(c)(-1), and sustain 60 cycles with an upper-limit capacity of 1000 mAh g(c)(-1). The strategy developed here provides insightful perspectives in designing carbon/metal hybrid electrodes for LOBs. (C) 2016 Elsevier Ltd. All rights reserved.