醇溶剂对炭气凝胶结构和电化学性能的影响

以间苯二酚和甲醛为原料、六次甲基四胺(HMTA)为催化交联剂,在不同种类醇溶剂中通过溶液 - 溶胶 - 凝胶、常温常压干燥和炭化处理制备炭气凝胶.N2吸附测试表明,醇溶剂体系制备炭气凝胶的比表面积在650～740 m2/g之间.乙醇为溶剂制备的炭气凝胶在20～40 nm有集中孔径分布,异丙醇为溶剂时孔径集中在3～4 nm之间,而以甲醇为溶剂时中孔含量相对较少.采用直流充放电法、交流阻抗法和循环伏安法测定以上述炭气凝胶为电极的超级电容器的电化学性能,结果表明,以乙醇为溶剂制备的炭气凝胶电极电容性能最佳,在0.5 A/g充放电时电极的比电容为180 F/g ,电流密度增大10倍容量保持率仍达到86%.合理的孔径分布和较大中孔有利于提高炭气凝胶电极的充放电特性.

The Influence of Alcoho-solvent on Structure and Electrochemical Performance of Carbon Aerogel

Carbon aerogel was prepared via a sol-gel process from the polycondensation of resorcinol and formaldehyde catalyzed by HMTA in alcohol-solvent, followed by drying at ambient pressure and py-rolysis at 900 ℃ under inert atmosphere and used as electrode materials for aqueous electric double-layer capacitors (EDLCs). The pore structure of carbon aerogel are influenced by the solvent used. A concentra-tive pore size distribution at 20~40 nm is observed in CRFP-E, and a sharp peak in the pore size range from 3 to 4 nm is detected in CRFP-I. The electrochemical behaviors were characterized by means of gal-vanostatic charging/discharging, cycle voltammetry and impedance spectroscopy. The results show that CRFP-E exhibites excellent specific dc capacitance over 180 F/g at 0. 5 A/g and the capacitance maintenance of CRFP-E can achieve 86 % at 5 A/g. The high current charge/discharge performance is improved by a reasonable pore size distribution.