三羧基丁烷膦酸锆/SPPEK复合膜在高温不同湿度下电导率

磺化杂萘联苯聚醚酮（SPPEK）膜在温度高于100℃时会因严重失水而导致电导率急剧下降。为此，合成出具有较高电导率的吸湿性质子导体1，2，4-三羧基丁烷-2-膦酸锆［Zr（PBTC）］，并将其掺杂到SPPEK中制备出Zr（PBTC）/SPPEK复合膜。实验表明，Zr（PBTC）的掺杂能有效提高复合膜在高温低湿情况下的吸水能力，从而提高其电导率。SPPEK膜在120℃、相对湿度为40％情况下电导率仅有约10^-4 S·cm^-1，而相同条件下30% Zr（PBTC）/SPPEK复合膜的电导率达到2×10^-3 S·cm^-1。而且相对湿度越小，复合膜电导率的提高幅度越大，在相对湿度小于20%时，复合膜的电导率大约比SPPEK膜高两个数量级。     

季铵盐化氧化石墨烯复合磺化聚磷腈质子交换膜的制备与表征

制备了一系列含有季铵盐化氧化石墨烯(QGO)的磺化聚磷腈类复合质子交换膜。通过对复合膜的稳定性能和电化学性能测试发现,复合膜(SP-x-QGO)的吸水率和溶胀度都低于纯磺化聚磷腈膜(SPFPP)。复合膜具有较好的抗氧化性能;复合膜SP-3-QGO在80℃完全吸水条件下的质子传导率为0.092 S/cm。结果表明,季铵盐化的氧化石墨烯(QGO)复合磺化聚磷腈类质子交换膜(SP-x-QGO)在燃料电池领域具有很大的发展前景。     

无机杂化倍半硅氧烷／磺化杂萘联苯聚醚酮质子导电复合膜

通过磺化反应制备了一系列不同磺化程度的磺化杂萘联苯聚醚酮（SPPEK）,采用共混法将无机杂化倍半硅氧烷（POSS）掺杂到IEC值为1．60的SPPEK中,通过溶液浇铸制得复合膜。对SPPEK／POSS复合膜进行了FTIR、TGA分析和SEM表观形貌观察。研究了SPPEK／POSS复合膜的吸水性、溶胀度和质子导电性,并与Nation 117进行对比。随着POSS的加入,复合膜的吸水性、溶胀度和氧化稳定性提高。SPPEK／POSS复合膜的室温电导率达到0．75×10^-2S·cm^-1,接近Nafion 117膜相同条件下的电导率（1．08×10^-2S·cm^-1）。随着温度升高,SPPEK／POSS复合膜的电导率逐渐增大。采用不同测试方法分别对复合膜的膜平面方向和厚度方向上的电导率进行了测试,表明在两个方向上的电导率相差较大,SPPEK／POSS复合膜室温下膜平面方向上的电导率达到2．1×10^-2S·cm^-1。     

磺化聚苯并咪唑/磺化聚醚砜酸碱复合质子交换膜的制备与表征

为提高膜的尺寸稳定性和阻醇性能,以磺化聚苯并咪唑(S-PBI)与高磺化度聚醚砜(ABPS)两种聚合物为原料,采用溶液共混的方法,制备了系列酸碱复合质子交换膜。研究了复合膜的甲醇溶胀性、吸水率、甲醇渗透系数、质子传导率随S-PBI含量的变化规律。研究表明,随着S-PBI含量的增加,膜的阻醇性能和尺寸稳定性明显提高;同时,复合膜具有较好的质子传导率,有望应用于直接甲醇燃料电池。     

基于含氟聚苯并咪唑/磺化壳聚糖复合质子交换膜的制备与表征

通过磺化反应在壳聚糖(CS)上引入磺酸基团制得具备良好质子传导能力的磺化壳聚糖(SPCS)。以含氟聚苯并咪唑(FPBI)为基体材料,通过掺杂磺化壳聚糖制备得到FPBI-SPCS复合质子交换膜。研究了SPCS的质量分数对复合膜的机械性能、热稳定性、吸水率、溶胀度、质子电导率等性能影响。结果表明,复合膜的质子电导率随着SPCS质量分数的增加而增加,但是吸水率、溶胀度却随着SPCS质量分数的增加而下降,复合膜依然能够保持良好的机械性能和热稳定性。FPBI-SPCS复合膜在80℃下最高电导率达18.52 m S/cm,有望在质子交换膜燃料电池中得到应用。     

BaCe_(0.8)Al_(0.2)O_3掺杂的SPEEK复合质子交换膜制备与性能

针对普通磺化聚醚醚酮(SPEEK)膜质子传导率较低的问题,提出无机掺杂的改善方法。采用共沉淀法制备BaCe_(0.8)Al_(0.2)O_3复合氧化物,将其掺杂到SPEEK膜基体中,并通过溶液浇铸法制得了SPEEK/BaCe_(0.8)Al_(0.2)O_3复合质子交换膜。对复合膜的尺寸稳定性、氧化稳定性、力学性能、质子传导率及微观形貌等进行了测试与表征。结果表明,BaCe_(0.8)Al_(0.2)O_3的掺杂可有效地提高复合膜的质子传导率。其中,SPEEK-BaCe_(0.8)Al_(0.2)O_3-9复合膜的质子传导率在80℃下达到0.187 S×cm~(-1),拉伸强度达29.43 MPa,单电池最大功率密度达0.82 W×cm~(-2),几乎可与普通的Nafion质子交换膜媲美。此外,掺杂还改善了复合膜的化学稳定性。     

聚醚砜/磺化聚醚醚酮共混膜的制备和性能

采用流延法制备了聚醚砜(PES)含量不同的PES/磺化聚醚醚酮(SPEEK)共混膜。PES与SPEEK具有良好的相容性。所制备PES/SPEEK共混膜的含水率、溶胀度和甲醇透过系数均随PES含量的增加而降低。虽然共混膜的质子传导性能有所降低.但阻醇性能和溶胀性能提高,这说明PES/SPEEK共混膜是一种很好的直接甲醇燃料电池用固体高分子电解质膜材料。     

PWA-13X-CS复合质子交换膜的性能研究

用13X分子筛负载无机质子导体-磷钨酸,然后加入壳聚糖(CS)中制备得到PWA-13X-CS复合质子交换膜,对其进行扫描电镜表征,测试了其吸水率、溶胀度、质子导电率、甲醇渗透系数等性质。结果表明PWA-13X-CS复合质子交换膜溶胀度较小,机械性能较好,质子导电率明显高于壳聚糖空白膜,且随温度升高呈上升趋势,其质子导电活化能低于壳聚糖空白膜,甲醇渗透系数小于Nafion117膜。将其与同样添加负载磷钨酸的13X分子筛的聚酰亚胺复合膜及聚乙烯醇复合膜性能进行对比,结果表明PWA-13X-CS复合质子交换膜综合性能较优,在直接甲醇燃料电池中具有较好的应用潜力。     

全氟磺酸质子交换膜的辐照改性研究

Nafion117膜是直接甲醇燃料电池广泛使用的全氟磺酸质子交换膜,但是它过高的甲醇渗透率和溶胀率降低了电池的性能.针对这一问题,采用60Co源对其进行辐照改性处理,并对改性后质子交换膜的性能进行了研究.通过对甲醇渗透率、溶胀率、含水率的测试,发现采用不同剂量γ-射线辐照对膜的性能影响不同,照射剂量适当的辐照处理能使质子交换膜的甲醇渗透率、溶胀率明显下降,并且不使质子交换膜的含水率明显降低.这一研究成果使得γ-射线辐照有望成为一种能实际应用的全氟磺酸质子交换膜的改性手段.     

介孔碳掺杂磺化聚酰亚胺质子膜的制备与性能

以有序介孔碳(CMK)为掺杂剂,在乙醇中超声分散后与磺化聚酰亚胺的间甲酚溶液直接混合,然后采用流延法制备掺杂质子交换膜。环镜扫描电子显微镜表征发现CMK在膜中分散均匀。通过吸水率、溶剂吸收率、尺寸变化、电导率、甲醇透过率、力学性能及稳定性等测试发现掺杂膜虽然电导率有所下降,但其吸水率下降了15%~26%;抗溶胀性提高了15%~30%;热稳定性提高了约20~30℃;抗氧化性增大了1.3~1.5倍;水稳定性和力学性能也显著提高。     

Sulfonated poly(ether ether ketone)/zirconium tricarboxybutylphosphonate composite proton-exchange membranes for direct methanol fuel cells

Sulfonated poly(ether ether ketone) (SPEEK) is a very promising alternative membrane material for direct methanol fuel cells. However, with a fairly high degree of sulfonation (DS), SPEEK membranes can swell excessively and even dissolve at high temperature. This restricts membranes from working above a high tolerable temperature to get high proton conductivity. To deal with this contradictory situation, insolvable zirconium tricarboxybutylphosphonate (Zr(PBTC)) powder was employed to make a composite with SPEEK polymer in an attempt to improve temperature tolerance of the membranes. SPEEK/Zr(PBTC) composite membranes were obtained by casting a homogeneous mixture of Zr(PBTC) and SPEEK in N,N-dimethylacetamide on a glass plate and then evaporating the solvent at 60°C. Many characteristics were investigated, including thermal stability, liquid uptake, methanol permeability and proton conductivity. Results showed significant improvement not only in temperature tolerance, but also in methanol resistance of the SPEEK/Zr(PBTC) composite membranes. The membranes containing 30 wt-% ∼ 40 wt-% of Zr(PBTC) had their methanol permeability around 10^-7 cm²·s^-1 at room temperature to 80°C, which was one order of magnitude lower than that of Nafion ^¯115. High proton conductivity of the composite membranes, however, could also be achieved from higher temperature applied. At 100% relative humidity, above 90°C the conductivity of the composite membrane containing 40 wt-% of Zr(PBTC) exceeded that of the Nafion ^¯115 membrane and even reached a high value of 0.36 S·cm^-1 at 160°C. Improved applicable temperature and high conductivity of the composite membrane indicated its promising application in DMFC operations at high temperature.     

Sulfonated poly(ether ether ketone)/zirconium tricarboxybutylphosphonate composite proton-exchange membranes for direct methanol fuel cells

Sulfonated poly(ether ether ketone) (SPEEK) is a very promising alternative membrane material for direct methanol fuel cells. However, with a fairly high degree of sulfonation (DS), SPEEK membranes can swell excessively and even dissolve at high temperature. This restricts membranes from working above a high tolerable temperature to get high proton conductivity. To deal with this contradictory situation, insolvable zirconium tricarboxybutylphosphonate (Zr(PBTC)) powder was employed to make a composite with SPEEK polymer in an attempt to improve temperature tolerance of the membranes. SPEEK/Zr(PBTC) composite membranes were obtained by casting a homogeneous mixture of Zr(PBTC) and SPEEK in N,N-dimethylacetamide on a glass plate and then evaporating the solvent at 60°C. Many characteristics were investigated, including thermal stability, liquid uptake, methanol permeability and proton conductivity. Results showed significant improvement not only in temperature tolerance, but also in methanol resistance of the SPEEK/Zr(PBTC) composite membranes. The membranes containing 30 wt-% ∼ 40 wt-% of Zr(PBTC) had their methanol permeability around 10⁻⁷ cm²·s⁻¹ at room temperature to 80°C, which was one order of magnitude lower than that of Nafion?115. High proton conductivity of the composite membranes, however, could also be achieved from higher temperature applied. At 100% relative humidity, above 90°C the conductivity of the composite membrane containing 40 wt-% of Zr(PBTC) exceeded that of the Nafion?115 membrane and even reached a high value of 0.36 S·cm⁻¹ at 160°C. Improved applicable temperature and high conductivity of the compositemembrane indicated its promising application inDMFC operations at high temperature. __________ Translated from Acta Polymerica Sinica, 2007, (4): 337–342 [译自:高分子学报]     

Characterization and application of composite membranes in DMFC

The present work focuses on the characterization of membranes for direct methanol fuel cells (DMFC), prepared using composites of sulfonated poly(ether ether ketone) (sPEEK, with sulfonation degree, SD, of 42 and 68%) as polymer matrix. This polymer was inorganically modified incorporating different amounts of zirconium phosphate (ZrPh) pretreated with n-propylamine and polybenzimidazole (PBI). The investigated properties were: proton conductivity, water and aqueous methanol swelling, permeability coefficients for DMFC species and morphology. DMFC tests were performed at 110 °C with relative humidity (r.h.) in the cathode feed of 100 and 138%. The results obtained show that the inorganic modification of the polymer decreases the proton conductivity, water and aqueous methanol swelling and permeability towards DMFC species. In terms of morphology, it was found that the applied procedure enabled the preparation of membranes with good compatibility between inorganic and organic components. In terms of the DMFC tests of the composite membranes, working with the cathode feed at 100% r.h., the unmodified sPEEK membrane with SD = 42% proved to have the best performance, although with higher methanol crossover. In contrast, for r.h. of 138%, the best performance was achieved by the sPEEK composite membrane with SD = 68 and 20.0 wt.% of ZrPh and 11.2 wt.% of PBI.     

Novel Nafion/Hydroxyapatite composite membrane with high crystallinity and low methanol crossover for DMFCs

Summary Novel Nafion/Hydroxyapatite (HA) composite membrane with high crystallinity was fabricated to suppress methanol crossover for direct methanol fuel cell (DMFC) applications. In this study, water and methanol diffusivity were evaluated through water-methanol sorption/desorption test and methanol permeation experiments. It was shown that the water-methanol diffusivity and methanol crossover for the composite membranes decrease as HA increases. Structural variation was investigated with wide-angle x-ray. As a result, it was found that the crystallinity of composite membranes increases with HA whereas water uptake content decreases gradually. Methanol permeability using a diffusion cell reduced in the composite membranes, suggesting that high crystallinity and low water uptake of composite membrane result in the suppression of methanol crossover due to the incorporation of HA into Nafion structure.     

Sulfonated poly(ether sulfone)/phosphotungstic acid/attapulgite composite membranes for direct methanol fuel cells

Novel composite sulfonated poly(ether sulfone)(SPES)/phosphotungstic acid (PWA)/attapulgite (AT) membranes were investigated for direct methanol fuel cells (DMFCs). Physical–chemical properties of the composite membranes were characterized by FTIR, DSC, TGA, SEM‐EDX, water uptake, tensile test, proton conductivity, and methanol permeability. Compared with a pure SPES membrane, PWA, and AT doping in the membrane led to a higher thermal stability and glass transition temperature (T_g) as revealed by TGA and DSC. Tensile test indicated that lower AT content (3%) in the composite can significantly increase the tensile strength, while higher AT loading demonstrated a smaller contribution on strength. Proper PWA and AT loadings in the composite membranes can increase the proton conductivity and lower the methanol cross‐over. The proton conductivity of the SPES‐P‐A 10% composite membrane reached 60% of the Nafion 112 membrane conductivity at room temperature while the methanol permeability was only one‐fourth of that of Nafion 112 membrane. This excellent performances of SPES/PWA/AT composite membranes could indicate a potential feasibility as a promising electrolyte for DMFC. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

PWA/silica doped sulfonated poly(ether sulfone) composite membranes for direct methanol fuel cells

A novel sulfonated poly(ether sulfone) (SPES)/phosphotungstic acid (PWA)/silica composite membranes for direct methanol fuel cells (DMFCs) application were prepared. The structure and performance of the obtained membranes were characterized by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), water uptake, proton conductivity, and methanol permeability. Compared to a pure SPES membrane, PWA and SiO₂ doped membranes had a higher thermal stability and glass transition temperature (T_g) as revealed by TGA‐FTIR and DSC. The morphology of the composite membranes indicated that SiO₂ and PWA were uniformly distributed throughout the SPES matrix. Proper PWA and silica loadings in the composite membranes showed high proton conductivity and sufficient methanol permeability. The selectivity (the ratio of proton conductivity to methanol permeability) of the SPES‐P‐S 15% composite membrane was almost five times than that of Nafion 112 membrane. This excellent selectivity of SPES/PWA/silica composite membranes indicate a potential feasibility as a promising electrolyte for DMFC. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Enhanced transport properties in polymer electrolyte composite membranes with graphene oxide sheets

Polymer electrolyte membranes have been widely investigated for high performance fuel cells. Here, we report the synthesis of ionic conductive Nafion/graphene oxide (GO) composite membranes for application in direct methanol fuel cells. GOs interact with both the non-polar backbone and the polar ionic clusters of Nafion because of their amphiphilic characteristics attributable to hydrophobic conjugation and hydrophilic functional groups. Accordingly, GO sheets serve to modify the microstructures of two domains of Nafion. In particular, the transport properties of Nafion are favorably manipulated by the incorporation of GO. This modulated the ionic channels of Nafion and decrease methanol crossover while preserving ionic conductivity. Furthermore, strong interfacial interactions due to the insertion of GO nanofillers into the Nafion matrix improve the thermal and mechanical properties of the material. In particular, we exploit Nafion/GO composite membrane as electrolyte material for direct methanol fuel cell (DMFC) in order to resolve current issue of methanol crossover. This composite membrane-based DMFC compared to the Nafion 112-based DMFC remarkably enhanced cell performance, especially in severe operating conditions.     

Effect of dispersion state of Cloisite15A® on the performance of SPEEK/Cloisite15A nanocomposite membrane for DMFC application

The introduction of 2,4,6‐triaminopyrimidine (TAP) into sulfonated poly(ether ether ketone) (SPEEK)/Cloisite15A® nanocomposite membranes were investigated for the purpose of maintaining low methanol permeability and suppressing swelling in direct methanol fuel cell (DMFC). SPEEK with 63% of degree of sulfonation (DS) was prepared by sulfonation of PEEK. Cloisite15A (7.5 wt %) along with various weight loading of TAP was incorporated into SPEEK matrix via solution intercalation method. The effect of TAP loading on the SPEEK/Cloisite15A/TAP morphology was studied. The beneficial impact of the SPEEK/Cloisite15A/TAP morphology on the physicochemical properties of the membrane was further discussed. Swelling behavior, ion exchange capacity (IEC), proton conductivity, and methanol permeability of the resultant membranes were determined as a function of Cloisite15A and TAP loadings. Uniform distribution of Cloisite15A particles in the SPEEK polymer matrix in the homogenous SPEEK/Cloisite15A/TAP nanocomposite membranes was confirmed by scanning electron microscopy and X‐ray diffraction. The water uptake of the SPEEK nanocomposite membranes decreased dramatically in the presence of TAP. The significant selectivity of SP/7.5/7.5 nanocomposite membranes could indicate a potential feasibility as a promising electrolyte for DMFC. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012