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The sulfonated poly (ether ketone) (SPEEK) with the combination of ethylene diamine modified strontium ferrite (SrFeO3 NH2) 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.

Polybenzimidazole (PBI)-sulfonated nano titania (S-TiO2) polymer composite membranes have been prepared by solvent casting technique for high temperature polymer electrolyte membrane (HT-PEM) fuel cells. X-Ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy was used to characterize the polymer structure and confirm the complexation of the sulfonated titania inside the polymer matrix. The highest proton conductivity obtained was 0.091 S cm−1 at 160 °C. The temperature dependent proton conductivity of the phosphoric acid doped proton conducting polymer electrolyte exhibits an Arrhenius relation and Grotthuss mechanism. Thermal gravimetric analysis (TGA) showed that all the prepared proton conducting polymer membrane exhibit good thermal stability. The morphological behaviors of the prepared proton conducting polymer electrolytes were depicted by scanning electron microscope (SEM) micrograph. The prepared composite membranes were characterized by proton conductivity, durability and mechanical strength. The acid uptake of the PBI-sulfonated titania blended membrane was found to be higher than that of the pristine PBI. The fabricated composite membrane with the highest conductivity exhibited a maximum current density of 0.89 A cm−2 through the high proton conductivity.

Nanocomposite membranes are synthesized by the combination of sulfonated poly(ether ether ketone) (SPEEK), poly(ethylene glycol) (PEG), and 3-aminopropyl triethoxysilane (APTEOS)-modified CaTiO3. F...

The sulfonated poly(ether ether ketone) (SPEEK) membrane has substantial property only with unification of acid-polymer and nanoparticles. The high stability of acid-based sulfonated poly(vinylidene fluoride-co-hexafluoropropylene) polymer is tailored with the SPEEK membrane to fine-tune the membrane stability, causing depletion in ionic conductivity. Various quantities of lanthanum zirconate (La₂Zr₂O₇) (2, 4, 6, and 8 wt %) nanoparticles were impregnated into the blend membrane to elevate the ionic conductivity with enriched stability. The effects of more hydrophilic domains facilitate the proton hopping mechanism. The distinct properties of the prepared membrane are examined using X-ray diffraction (XRD), NMR, field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), tensile tests, water uptake, etc. The homogeneous appearances of the membrane morphology are exposed. The thermal and mechanical stability of the nanocomposite membranes is validated by a tensile test, and obtained results are better than those of the pure SPEEK membrane. The maximum proton conductivity of the SPEEK/SPVdF-co-HFP/La₂Zr₂O₇ (6 wt %) membrane is 1.53 × 10–² S cm–¹. The voltage–current measurement of the membrane is obtained in the single cell type at 80 °C under relative humidity (RH) 75% with the H₂/O₂ gas flow. The maximum current density and power density obtained are 78 mA cm–² and 335 mW cm–².

The present work deals with the effect of phosphotungstic acid (PWA) in the sulfonated poly (ether ether ketone) (SPEEK)/poly amide imide (PAI) polymer matrices. These membranes are prepared using solvent casting method. The complexation and structural analysis are characterized by FTIR and XRD studies respectively. The obtained results of ion exchange capacity, water uptake, and proton conductivity show their physico-chemical properties of the prepared composite membranes significantly enhanced after the incorporation of PWA. At ambient temperature, 5.6 × 10−2 S/cm is the maximum conductivity achieved for the 20 wt% PWA-doped SPEEK/PAI membrane. The TGA/DTG thermograms show that the membrane retains good thermal stability with 54–57% of char yield which having maximum proton conductivity at different temperatures in the range of about 10−2 S/cm because of the Keggin unit structure of PWA. The SEM micrograph reveals the dispersion of PWA in the SPEEK/PAI matrices. The insertion of PWA in the SPEEK/PAI matrix exhibiting better properties with Bacillus amyloliquefaciens is used to carry out the performances in the microbial fuel cell for bioelectricity generation. The maximum obtained voltage and power density are 786 mV and 113 mW/m2, respectively, with current density of 207 mA/m2.

In recent decades, there has been a need for novel advancement of sustainable non-fluorinated polymer electrolyte membranes for proton exchange membrane fuel cell (PEMFC) applications. The set forth strategy aims to ameliorate proton conduction of sulfonated polyethersulfone (SPES) polymer membranes with a distinct mixture of barium cerate (BCO) and neodymium-doped barium cerate (BCNO) perovskites developing cationic composite membranes (CCMs) prepared through a technique of solvent casting. The CCMs were subjected to analysis of their mechanical, structural, chemical compositional, thermal, morphological, oxidative, physicochemical, electrochemical and fuel cell polarization performance respectively. Acceptor doping of the trivalent neodymium group at the B site of BCO increases the number of oxygen vacancies and improves ionic conduction. The CCM of neodymium-doped barium cerate demonstrates a higher proton conductivity of 42.2 mS cm-1 with a lower activation energy of 6.80 kJ mol-1 at 80 °C. The maximum current density and power density with the OCV of 0.93 V for the neodymium-doped barium cerate membrane are 397 mA cm-2 and 117 mW cm-2, which is 1.8 times greater than that of the pure SPES membrane. On the basis of polarization performance, the SPES membrane with neodymium-doped barium cerate has great potential in highly-efficient PEMFC applications.