The composite of cobaltosic sulfide/electrospun carbon nanofibers (Co3S4/ECs) with high catalytic activity have been successfully synthesized by combining the versatility of the electrospunning technique and following a hydrothermal synthesis method. And the composite of Co3S4/ECs was introduced into dye-sensitized solar cells (DSCs) as counter electrode (CE) for the first time. Combining a new electrolyte with iodide free redox couples involving Co3+/2+, the Co3S4/ECs composite demonstrated good performance in DSCs. Under AM 1.5G illuminations, the DSCs based on Co3S4/ECs composite CE achieved a high power conversion efficiency (PCE) of 9.23%, which increased by 10.1% compared to the DSCs based on Pt CE (8.38%). (C) 2016 Elsevier B.V. All rights reserved.