In general, air electrodes are fabricated by mixing an oxide catalyst, carbon, and a binder. However, a nanosized oxide catalyst may not disperse homogeneously; instead, it easily aggregates, thus limiting its full catalytic activity. In order to solve this problem, a carbon nanofiber (CNF)/Co3O4 composite was prepared and characterized in this work. A polydopamine layer was used as a binding agent for the CNFs and Co3O4. The polydopamine-assisted CNF/Co3O4 composite was characterized by homogeneously dispersed nanosized Co3O4 particles, resulting in a wide catalytic active area. The electrode containing the CNF/Co3O4 composite was prepared via the buckypaper method and exhibited superior capacity, lower overpotential, and better cyclic performance than an electrode containing commercial Co3O4 nanoparticles and CNFs. This result indicates that the CNF/Co3O4 composite is an effective catalyst for air electrodes of lithium-air cells. (C) 2014 Elsevier B.V. All rights reserved.