The sulfonated poly (ether ketone) (SPEEK) with the combination of ethylene diamine modified strontium ferrite (SrFeO3NH2) have been electrospun by the electrospinning technique to produce the nanofibers mats (SFN). These are filled with SPEEK matrices to construct the dual interfacial sites in the composite membranes (SPEEK/SFN) for the high proton transporting pathways. In this method, two distinctive interfacial channels are formed inside the SFN nanofibers and along with the SPEEK/SFN matrix, in which highly ordered acid–base (–SO−….+H2N–) pairs are created. These provide the strong electrostatic attraction and improve the structural stability by controlled polymers chain movement. The dual acid-base interfacial sites at SFN (inside) and SPEEK/SFN (along) matrices could create the well-interconnected channels and aids the proton transporting pathways. These confer the ultrafast proton migration via Grotthuss hopping by supporting proton donors and acceptors pairs (–SO−….+H2N–). Mainly, SPEEK/SFN3 obtains outstanding conductivity of 94.87 mS cm−1 and power density of 341.22 mW cm−2 under 80 °C and 100%RH. SPEEK/SFN3 achieved the excellent value of young modulus (897 MPa) and weight retention (92.5 wt% at 185 °C) via mechanical and thermal analysis. The overall test showed the SPEEK/SFN is a better performer than SPEEK (casting) membrane for PEM.