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首页> 外文期刊>Journal of Materials Chemistry, A. Materials for energy and sustainability >Carbogels: carbonized conducting polyaniline/poly(vinyl alcohol) aerogels derived from cryogels for electrochemical capacitors
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Carbogels: carbonized conducting polyaniline/poly(vinyl alcohol) aerogels derived from cryogels for electrochemical capacitors

机译：肉凝胶：碳化导电聚苯胺/聚（乙烯醇）气凝胶衍生自用于电化学电容器的冷冻机

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摘要

Polyaniline cryogels supported with poly(vinyl alcohol) represent soft conducting macroporous materials suitable for conversion to aerogels by freeze-drying and, subsequently, to nitrogen-containing carbogels by carbonization in an inert atmosphere at 500-600 degrees C. The process was followed by thermogravimetric analysis and Raman spectroscopy at the molecular level. The spectral features indicate a significant degree of structural disorder in the material due to the extensive nitrogen and oxygen incorporation into the carbon sp(2) network, which is important for the improvement of capacitive performance. The macroporous morphology is preserved after carbonization but the specific surface area increased from 12 to 680 m(2) g(-1) after exposure to 500 degrees C in an inert atmosphere. The original conductivity of the cryogel swollen with an acid solution, 0.07 S cm(-1), was reduced to 2 x 10(-4) S cm(-1) for the aerogel and again to 10(-9) S cm(-1) as the carbonization progressed. The impedance spectra display Maxwell-Wagner-Sillars relaxation typical of heterogeneous composite systems with the contribution of ionic conductivity. The decrease in conductivity is in agreement with the significant drop in the static dielectric constant observed by broad-band dielectric spectroscopy and decrease in the spin number determined by electron paramagnetic resonance spectroscopy. Switching in the capacitive response from that dominated by faradaic surface processes at lower treatment temperatures to that of double-layer charging at elevated temperatures is evidenced, while the correlation between surface spin density and specific capacitance is emphasized. The results can be used as guidance for the rational design of novel active materials for electrochemical capacitors.
机译：用聚苯胺冷冻胶质凝胶（乙烯醇）表示，柔软的传导大孔材料，适用于通过冷冻干燥转化为气动凝胶，然后通过在惰性气氛中碳化在500-600℃下碳化。该过程随后分子水平的热重分析和拉曼光谱。光谱特征在碳SP（2）网络中的广泛的氮气和氧气掺入，光谱特征表示材料中的显着程度的结构障碍，这对于改善电容性能是重要的。在碳化之后保持大孔形态，但在惰性气氛中暴露于500℃后，比表面积从12至680m（2 )g（-1）增加。用酸溶液，0.07scm（-1）的冷冻胶溶胀的原始电导率降至气凝胶的2×10（-4）厘米（-1），并再次降至10（-9）厘米（ -1）随着碳化进展。阻抗谱显示Maxwell-Wagner-Sillars宽松，典型的异构复合系统具有离子电导率的贡献。导电性的降低与通过宽带介电光谱观察到的静态介电常数的显着下降，并通过电子顺磁共振光谱法确定的旋转数量减小。从较低处理温度下切换到电容响应，从较低的处理温度下沿着升高的温度下的双层充电的处理，同时强调表面旋转密度和特定电容之间的相关性。结果可用作电化学电容器新型活性材料的合理设计的指导。

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