炭凝胶的制备及其电化学电容性能

采用新型聚合物混合法,在合成炭前驱体聚合物的单体溶液中混入热不稳定的聚乙二醇,制得了比表面积达710m2/g,平均孔径为2.8nm的新型中孔炭干凝胶PEG-RF炭.X射线衍射、热重分析及N2等温吸脱附测试结果表明,炭前驱体的微相分离结构和热稳定性较差的聚乙二醇的存在导致了炭干凝胶中孔特征孔隙结构的形成.在30％H2SO溶液中,对PEG-RF炭和比表面积迭1720 m2/g的微孔T82型活性炭的电化学电容性能进行了对比研究。研究结果表明:当放电比电流为0.2A/g时,PEG-RF炭和T82型活性炭的比容量分别为36F/g和48F/g;当放电比电流增至1A/g时,PEG-RF炭和T82型的比容量分别为105F/g和94F/g;PEG-RF炭具有比T82型活性发更优异的电化学电容性能,两者孔隙结构的差异导致了炭凝胶电化学电容性能的差异.

Preparation and electrochemical capacitance of carbon xerogel

With the monomers of resorcinol and formaldehyde as precursor, mixing polyethylene glycol in the precursor, PEG-RF carbon with 710 m~2/g in specific surface and 2.8 nm in average pore diameter was synthesized by polymer blend method. The results of thermogravimetric analysis, X-ray diffraction and N_2 sorption isotherms indicate that the structure of pyrolytic carbon xerogel together is formed due to the phase separation structure of mixing organic xerogel and the thermal unstability of PEG. Cyclic voltammetry and galvanostatic charge/discharge were used to study the electrochemical capacitance performance of PEG-RF carbon and T82 carbon with specific surface 1 720 m~2/g and average pore diameter 0.95 nm. The result shows that the specific capacitance of PEG-RF carbon and T82 carbon is 36 F/g and 48 F/g, respectively, when the discharge current is 0.2 A/g in 30% H_2SO_4 solution; and 105 F/g and 94 F/g, respectively, when the discharge current increases to 1 A/g. Due to differences of the pore structure, PEG-RF carbon has better electrochemical capacitance than T82 carbon.