The effect of nanoclay cloisite Na+ on the mechanical and conductive properties of ionic liquids (ILs) doped sulfonated ABPBI (SABPBI) composite membranes for high temperature proton electrolyte membrane (PEM) applications were investigated in this report. The composite SABPBI membranes with well-dispersed cloisite Na+ showed great improvement in mechanical properties with the increase of over 90% in ultimate tensile strength and 40% in Young's modulus, respectively, compared with those of pristine ABPBI membrane. The ILs absorption was also increased due to the incorporation of well-dispersed cloisite Na+, resulting in significant increase in the ionic conductivities of SABPBI membranes at the temperatures above 100 degrees C. The highest conductivities were 4.0 x 10(-2) S/cm at 220 degrees C for [HMIM]Cl doped 3 wt% SABPBI composite membranes (doping level 1.32), and 9.6 x 10(-3) S/cm x 10(-3) S/cm at 220 degrees C for [TMG][BF4] doped SABPBI composite membranes (doping level 1.37), respectively. Copyright (C) 2015, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.