Interplay between Mechanical, Electrical, and Thermal Relaxations in Nanocomposite Proton Conducting Membranes Based on Nafion and a [(ZrO2)路(Ta2O5)0.119] C
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- 作者：Vito Di Noto ; Matteo Piga ; Guinevere A. Giffin ; Keti Vezz霉 ; Thomas A. Zawodzinski
- 刊名：The Journal of the American Chemical Society
- 出版年：2012
- 出版时间：November 21, 2012
- 年：2012
- 卷：134
- 期：46
- 页码：19099-19107
- 全文大小：653K
- 年卷期：v.134,no.46(November 21, 2012)
- ISSN：1520-5126
文摘
The thermal, mechanical, and electric properties of hybrid membranes based on Nafion that contain a [(ZrO2)路(Ta2O5)0.119] 鈥渃ore鈥搒hell鈥?nanofiller are elucidated. DSC investigations reveal the presence of four endothermic transitions between 50 and 300 掳C. The DMA results indicate improved mechanical stability of the hybrid materials. The DSC and DMA results are consistent with our previous suggestion of dynamic R鈥揝O3H路路路[ZrTa] cross-links in the material. These increase the thermal stability of the 鈭扴O3H groups and the temperature of thermal relaxation events occurring in hydrophobic domains of Nafion. The broadband electrical spectroscopic analysis reveals two electric relaxations associated with the material鈥檚 interfacial (蟽IP) and bulk proton conductivities (蟽EP). The wet [Nafion/(ZrTa)1.042] membrane has a conductivity of 7.0 脳 10鈥? S cm鈥? at 115 掳C, while Nafion has a conductivity of 3.3 脳 10鈥? S cm鈥? at the same temperature and humidification conditions. 蟽EP shows VTF behavior, suggesting that the long-range conductivity is closely related to the segmental motion of the Nafion host matrix. Long-range conduction (蟽EP) occurs when the dynamics of the fluorocarbon matrix induces contact between different delocalization bodies (DB), which results in proton exchange processes between these DBs.