Preparation and Characterization of Sulfonated Poly (ether ether ketone)/Phosphated Zirconia Nanoparticles Composite Proton-conducting Membranes (original) (raw)
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International Journal of Hydrogen Energy, 2016
In this study, sulfated zirconia (SZ) nanoparticles were used as inorganic additives in order to improve physicochemical properties of sulfonated poly (ether ether ketone) (SPEEK) membranes especially for fuel cell application at intermediate temperature. Interactive effects of SPEEK sulfonation time and the content of incorporated additive (as the factors) were studied on the proton conductivity and the oxidative stability of the nanocomposite membranes (as the responses) through the response surface method (RSM) using the central composite design (CCD). The optimum parameters were 6.9 h sulfonation time and 5.94 wt. % of sulfated zirconia that represented proton conductivity of 3.88 mS cm À1 (at 100 C and 100% RH) and oxidative stability of 102 min. The sulfonation time had more effect on both responses. Furthermore, the addition of SZ nanoparticles improved both of oxidative stability and proton conductivity. The morphology, thermal and mechanical properties of optimized nanocomposite membrane were investigated by FESEM, TGA, DSC and tensile strength test, respectively. Also, the XRD, TGA, FTIR, EDX and TEM analysis were conducted to characterize the SZ nanoparticles.
European Polymer Journal, 2007
Biodegradable solid polymer electrolytes based on PVA (polyvinyl alcohol) and amino acid (proline) with different molar mass percentages of ammonium chloride (NH 4 Cl) were prepared by solution-casting technique using distilled water as solvent. Their structural, thermal, vibrational, and electrical properties were studied. XRD analysis confirms the amorphous nature of the polymer electrolytes. DSC measurements show a decrease in T g with increasing salt concentration. The FTIR analysis reveals the complex formation between the PVA, proline, and ammonium chloride. Transference numbers for the proton-conducting polymer electrolytes have been measured. The maximum ionic conductivity has been found to be 7.01 × 10 −4 S/cm at ambient temperature for 75 Mwt% PVA;25 Mwt% proline:0.3 (m.m.%) of NH 4 Cl polymer electrolyte using AC impedance analyzer. The temperaturedependent conductivity of the polymer membranes obeys Arrhenius behavior. The highest ionic conductivity polymer electrolyte has low activation energy of 0.07 eVamong the prepared polymer electrolytes. An electrochemical stability window of 3.10 V has been measured using linear sweep voltammetry for the highest ionic conducting membrane. The highest conductivity polymer electrolyte 75 Mwt% PVA:25 Mwt% proline:0.3 (m.m.%) NH 4 Cl has been used to construct a primary proton battery and fuel cell.
Chemistry of materials : a publication of the American Chemical Society, 2010
Because of their strong acidity and water affinity, sulfated zirconia nanoparticles were evaluated as inorganic additives in the formation of composite Nafion-based membranes. Two types of sulfated zirconia were obtained according to the preparation experimental conditions. Sulfated zirconia-doped Nafion membranes were prepared by a casting procedure. The properties of the composite membranes were compared with those of an unfilled Nafion membrane obtained by the same preparation method. The water uptake, measured at room temperature in a wide relative humidity range, was higher for the composite membranes, this confirming the hydrophilic nature of the selected additives. The membrane doped by zirconia particles having the highest sulfate group concentration showed the highest water diffusion coefficient in the whole range of temperature and relative humidity investigated because of the presence of SO 4 2providing extra acid sites for water diffusion. The proton diffusivity calculated from impedance spectroscopy measurements was compared with water self-diffusion coefficients measured by NMR spectroscopy. The difference between proton and water diffusivity became significant only at high humidification levels, highlighting the role of water in the intermolecular proton transfer mechanism. Finally, great improvements were found when using the composite membrane as electrolyte in a fuel cell working at very low relative humidity.
Chemistry of Materials, 2010
Because of their strong acidity and water affinity, sulfated zirconia nanoparticles were evaluated as inorganic additives in the formation of composite Nafion-based membranes. Two types of sulfated zirconia were obtained according to the preparation experimental conditions. Sulfated zirconia-doped Nafion membranes were prepared by a casting procedure. The properties of the composite membranes were compared with those of an unfilled Nafion membrane obtained by the same preparation method. The water uptake, measured at room temperature in a wide relative humidity range, was higher for the composite membranes, this confirming the hydrophilic nature of the selected additives. The membrane doped by zirconia particles having the highest sulfate group concentration showed the highest water diffusion coefficient in the whole range of temperature and relative humidity investigated because of the presence of SO 4 2providing extra acid sites for water diffusion. The proton diffusivity calculated from impedance spectroscopy measurements was compared with water self-diffusion coefficients measured by NMR spectroscopy. The difference between proton and water diffusivity became significant only at high humidification levels, highlighting the role of water in the intermolecular proton transfer mechanism. Finally, great improvements were found when using the composite membrane as electrolyte in a fuel cell working at very low relative humidity.
Organic-Inorganic Composite Polymer Electrolyte Membranes, 2017
Proton-exchange membrane fuel cells (PEMFCs) are one of the most promising commercial technologies used to produce clean energy with high efficiency, energy density, and low emission of harmful gases. Proton-exchange membrane (PEM) is a major part of fuel cell that plays an important role. However, these membranes are very expensive, thermally degradable at high temperature, and conduct protons only in aqueous condition that limits the performance of PEMFC. However, at lower operating temperature, the performance of fuel cell is affected, due to slow electrode kinetics. Recently, great attention has been paid to develop high temperature-tolerant PEM with high proton conductivity. The organic-inorganic composite PEM that can work at high temperature with high proton conductivity is being developed. These organic-inorganic membranes are created by incorporation of metal oxide nanoparticles in the polymer host such as Nafion with strong acid site. These membranes provide high proton conductivity, and chemical and thermal stability to PEMs. Sulfated zirconia (S-ZrO 2), a strongest super acid possessing protogenic groups, is being used as an inorganic filler for composite membranes which showed improved operation at elevated temperature. This chapter presents an overview of the commonly used polymer hosts and inorganic additives. The available literature on S-ZrO 2 nanohybrid membrane technology has been discussed in view of catalyzing the future research to develop more suitable PEM for fuel cell.
Macromolecular Materials and Engineering, 2018
when operating at elevated temperatures, researchers have focused on heat-resistant materials as electrolytes for application at intermediate temperatures. [3-7] One of such materials is a type of hydrocarbon polymers known as poly(ether ether ketone) (PEEK) which is converted to sulfonated poly(ether ether ketone) (SPEEK) during an electrophilic sulfonation reaction. [8-15] Due to the fact that pristine SPEEK suffers from major drawbacks at higher temperatures, that is, above 100 °C, the fillers are introduced into polymeric matrix to overcome them. [16-18] For instance, numerous additives such as zeolite, [8] aluminum oxide, [19] single-walled carbon nanotubes, [20] and zirconium oxide [21,22] were embedded into SPEEK matrix and possessed great properties. Besides, Du et al. [23] studied the compatibility of silica sulfuric acid (SSA) particles with SPEEK by fabricating a series of SSA/ SPEEK membranes. The proton conductivity, distribution of ionic clusters, water retention, and thermal behavior of the prepared SSA/SPEEK membranes were promoted. [23] In addition, the composites of SPEEK and surface-functionalized TiO 2 (hydrophilic and hydrophobic TiO 2) additives were investigated by Di Vona et al. [24] It was proved that different types of functionalities on the surface of the filler make variation in physicochemical properties of prepared nanocomposite membranes. Likewise, titania nanosheet (TNS)/SPEEK membranes were another interesting candidates for electrolytes of fuel cells working at medium temperatures (T > 100 °C). [25] Sulfated zirconia (SZ) superacid with favorable properties including high proton conductivity, thermal stability, and simple synthesis procedure, is considered a primary interest filler within composites. [26] The SZ fillers by representing a high conductivity of 3 mS cm −1 in Nafion/SZ composite membranes under completely dry condition received much attention for application in high-temperature fuel cells. [27] Zhang et al. [28] employed sulfated zirconia supported platinum catalyst (Pt-SZ) as a self-humidifying agent in SPEEK matrix for PEMFC application under low relative humidity condition. The Pt-SZ additives by providing additional acidic sites within the SPEEK/ Pt-SZ membrane made a general enhancement in terms of proton conductivity, power density, and water uptake (WU) at Sulfated Zirconia Fillers This study expresses that the characteristics of sulfated zirconia (SZ) nanostructure in sulfonated poly(ether ether ketone) (SPEEK)-based membranes is the key to optimize their properties for fuel cell applications. Two types of SZ treating in different thermal conditions are produced by precipitation and analyzed by X-ray diffraction, thermogravimetric analysis, Fourier transform infrared spectroscopy, energy-dispersive X-ray analysis, and transmission electron microscopy. Sulfate concentration on both types of SZ is changing from 0.54 to 1.45 wt% and thus the SZ samples differ in particle size and sulfate content. The nanocomposite membranes are prepared by incorporating 6 wt% of SZ samples into SPEEK matrix in casting procedure followed by performing electrochemical characterizations and impedance spectroscopy. Moreover, morphology, mechanical, and chemical stability of the membranes are investigated by field emission scanning electron microscopy, stress-strain, and ex situ Fenton's tests. The incorporation of SZ sample having more surface sulfate groups in the SPEEK matrix results in not only excessive oxidative stability and tensile strength but also more acidic sites for ion transport, promoting conductivity. Furthermore, both types of nanocomposite membranes show improved ionic conductivity and water affinity with a lower tendency to swell rather than the plain SPEEK membrane. It is proved that desired consequences of doping SZ into SPEEK matrix can be intensified by changing the physicochemical properties of sulfated zirconia nanoparticles.
International Journal of Hydrogen Energy, 2017
The present research focused on investigation of physicochemical and electrochemical properties of proton exchange membranes based on sulfonated poly (ether ether ketone) (SPEEK) by using zirconia nanoparticles. Plain and nanocomposite SPEEK membranes with different loadings of microwave-induced gel combustion synthesized ZrO 2 were fabricated. Sulfonation of polymer and nanoparticle production was confirmed by H NMR and XRD, respectively. Physical, chemical, and electrochemical properties of membranes were investigated by SEM, IEC, WU, EIS, tensile stressestrain, TGA, Fenton, and hydrolytic stability tests. H NMR spectra represented a DS of 65% for the sulfonated polymer. The prepared nanocomposite membranes possess improved thermal and mechanical stability with higher hydrolytic stability and enhanced oxidative stability. In addition, nanocomposite membranes exhibited higher water uptake with lower IEC. The hygroscopic zirconia nanoparticles resulted higher proton conductivity of nanocomposite membranes at temperatures upper than 80 C in comparison with pristine SPEEK membrane. All results showed the fabricated nanocomposite membranes have good physicochemical properties and promising future of the introduced approach for PEMFC applications.
International Journal of Energy Research, 2020
Simultaneous high proton conductivity with high oxidative stability is one of the major concerns in the proton exchange membrane (PEM) preparation. With this perspective, different loadings of the sulfated zirconia-titania, a binary metal oxide that possesses enhanced physicochemical properties, nanoparticle in sulfonated poly(ether ether ketone) (SPEEK) polymer were evaluated by the response surface method to obtain the novel PEM with boosted proton conductivity and oxidative stability. Two models for correlation of proton conductivity and oxidative stability (in Fenton solution) with two independent factors, including sulfonation time and the weight percent of the nanoparticle loading, were obtained by central composite design. The optimum parameters to attain the highest proton conductivity with oxidative stability are found to be the sulfonation time of 6.48 hours and the nanoparticle weight percent of 10.12%. The nanoparticle loading was found to be the more significant factor in the proton conductivity model, while the sulfonation time in the oxidative stability model was the main affecting factor. The optimal membranes were characterized by
International journal of electrochemical science
A composite Nafion-Sulfated Zirconia (SZrO 2 ) membrane was prepared and investigated in a solid polymer electrolyte (SPE) water electrolyzer at different temperatures. The performance was compared to a commercial Nafion 115 membrane of similar thickness. The cell equipped with Nafion -SZrO 2 showed better performance at intermediate temperatures. The current densities were 2.7 and 2.2 A·cm -2 at a terminal voltage of 1.8 V for the composite Nafion -SZrO 2 and Nafion 115, respectively, at 100°C and atmospheric pressure. The superior performance of the composite electrolyte was due to the strong acidity and water affinity of sulfated zirconia nanoparticles used as filler. Operation at intermediate temperatures in a solid polymer electrolyte water electrolyzer appears useful for a better thermal management of the heat released at high current densities.
Materials Letters, 2015
New proton conducting organic/inorganic nano hybrid polymer electrolyte membranes were synthe sized by solving casting method. Inorganic nanopowders were a layered double hydroxides (LDH) with Zn,Al cations in which heptamolybdate were inserted. These nanopowders were prepared by anion exchange method from hydrotalcite (LDH) with interlayer anions (NO 3). The sulfonated polymers were prepared by an electrophilic aromatic substitution reaction between the polymer and trimethylsylil cholorosulfonate (TMSCS). The composites membranes were characterized by FTIR and TGA and water uptake was determined. Electrochemical impedance spectroscopy (EIS) was used to study the proton conductivity of the membranes. EIS measurements were performed facing the membrane to different HCl concentrations (10 3 rc r10 1 M). It was concluded that these new composite membranes present good thermal properties and proton conductivity slightly higher than SPSU.