As a potential electrolyte for energy storage devices, mesoporous TiO2-doped epoxy-based composite electrolytes were fabricated. The presence of mesoporous TiO2 in the composites promotes the cross linking reaction of epoxy resin, as well as reduces the charge transfer resistance and favors the ionic transport, providing the composite electrolytes with enhanced electrochemical performance, mechanical strength and thermal stability. The highest ionic conductivity (11 x 10(-5) S cm(-1)), ionic transference number (0.661) and compression strength (5.06 MPa) were obtained for a composite electrolyte with 6 wt% doped mesoporous TiO2. The nano-structured reinforcing phase is beneficial to the enhancement in the electrochemical and mechanical performances of electrolyte simultaneously. (C) 2017 Elsevier B.V. All rights reserved.