A sponge-like cobalt sulfide/reduced graphene oxide (CoS/rGO) hybrid film is deposited on fluorine doped SnO2 (FTO) glass by electrophoretic deposition and ion exchange deposition, following by sodium borohydride and sulfuric acid solution treatment. The film is used as the counter electrode of dye-sensitized solar cells (DSSCs), and is characterized by field emission scanning electron microscopy, Raman spectroscopy, cyclic voltammetry, electrochemical impedance spectroscopy and Tafel measurements. The results show that the CoS counter electrode has a sponge structure with large specific surface area, small charge-transfer resistance at the electrode/electrolyte interface. The addition of rGO further improves the electrocatalytic activity for I-3(-) reduction, which results in the better electrocatalytic property of CoS/rGO counter electrodes than that of Pt counter electrode. Using CoS/rGO(0.2) as counter electrode, the DSSC achieves a power conversion efficiency of 9.39%; which is increased by 27.93% compared with the DSSC with Pt counter electrode (7.34%). (C) 2015 Elsevier B.V. All rights reserved.