Herein, we report the design and synthesis of a unique honeycomb-like Ni3S2 structure growing directly on the Ni foam skeleton (H-Ni3S2/NF) and its application in lithium-oxygen (Li-O-2) batteries as a free-standing cathode. Excellent electrocatalytic activity of honeycomb-like Ni3S2 and the unique network structure of Ni matrix can provide synergistic effect for facilitating electron transport and the diffusion of both oxygen and Li+, leading to the excellent electrochemical performance of Li-O-2 battery. Specifically, Li-O-2 batteries with H-Ni3S2/NF electrodes exhibit high energy efficiency (84.2%), outstanding cycle stability of over 116 cycles at limiting capacity of 4mA h cm(-2) and excellent rate capability (9.84 mAh cm(-2) at 12 mAcm(-2)). (C) 2018 Elsevier Ltd. All rights reserved.