It is vital to choose economical and environmentally friendly proton conductive materials to improve the performance of proton exchange membranes, which occupies a unique position in proton exchange membrane fuel cells. This paper reports a new proton conductive nanocomposite, that was named NbO2(OH)-PA prepared from phytic acid (PA) and NbCl5. NbO2(OH)-PA showed an excellent proton conductivity of 135 mS cm(-1) at 85 degrees C and 97% relative humidity. In addition, NbO2 (OH)-PA was combined with sulfonated poly (ether ketone) (SPEEK) in different proportions to form proton conductive membranes, that are labeled SPEEK-x NbO2(OH)-PA. SPEEK-0.9% NbO2(OH)-PA exhibited the best proton conductivity of 0.17 S cm(-1) at 80 degrees C in water. This work may provide new ideas for improving proton conductivity of membranes through simple methods. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.