A novel titanium foil substrate strategy for the synthesis of high electrocatalytic activity nickel sulfide/polyaniline/titanium (NiS/PANI/Ti) composite film with one-dimensional (1D) net-work structure by using an in situ electropolymerization route, and proposed as platinum (Pt)-free counter electrode (CE) catalyst for flexible dye-sensitized solar cells (FDSSCs). The photovoltaic performance of the FDSSC based on the NiS/PANI/Ti CE exhibits Jsc of 14.56 mA cm(-2), Voc of 0.743 V, FF of 0.68, and corresponding to the h of 7.35%, much higher photoelectric conversion efficiency than that of Pt/Ti CE (6.24%). The NiS/PANI/Ti CE with 1D net-work structure is characterized by using the scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and Tafel polarization plots. The NiS/PANI/Ti CE presents multiple functions, i. e., excellent conductivity, great electrocatalytic ability for iodine/triiodine, and lower charge transfer resistance of 1.48 +/- 0.02 ohm center dot cm(2) compared to the Pt/Ti electrode (2.25 +/- 0.02 ohm center dot cm(2)). The photocurrent-photovoltage (J-V) character curves are further used to calculate theoretical short-current densities and open-circuit voltage of the devices. Therefore, the NiS/PANI/Ti CE with 1D net-work structure can be considered as a promising and efficient CE for FDSSCs. (C) 2014 Elsevier Ltd. All rights reserved.