摘要/Abstract
本工作通过一步水浴法制备高氮/氧含量密胺树脂(MF), 引入阴离子型表面活性剂十二烷基硫酸钠(SDS)改变聚合物的反应历程, 使进入SDS胶束中的三聚氰胺与甲醛在盐酸催化条件下进行聚合反应, 高温碳化后成功制备MF衍生多孔碳材料. 对MF衍生多孔碳材料分别进行了扫描电镜、比表面积等表征, 结果表明, 其具有多孔互穿网络结构, 比表面积高达387.86 m2?g-1, 且孔径分布适宜(3.62 nm). 作为超级电容器(SCs)电极材料, 在1.0 A?g-1下的比电容值为349.6 F?g-1, 20.0 A?g-1时(254.6 F?g-1)仍能维持1.0 A?g-1时73.0%的电容保持率, 倍率性能优异. 该样品在10.0 A?g-1下循环15000次后的比电容值几乎没有衰减, 循环稳定性能优越. 此研究结果表明SDS可辅助提升MF衍生多孔碳材料的电容性能, 发展潜力巨大.
关键词: 密胺树脂, 十二烷基硫酸钠, 分级多孔结构, 高氮/氧含量, 高电容性能
Benefiting from the inducing effect of sodium dodecyl sulfate (SDS) during the polymerization process of melamine and formaldehyde, melamine resin (MF)-derived porous carbon materials with high nitrogen and oxygen content have been synthesized via an annealing-followed water bath method in this work. To study the effect of SDS on the synthesis and properties of MF-derived porous carbon materials, the microstructure and composition of as-prepared samples are characterized by scanning electron microscopy (SEM), nitrogen adsorption/desorption and X-ray photoelectron spectroscopy (XPS). It can be seen from SEM images that sample of the best additive amount (MFC-SDS30) has the interpenetrating network structure, which is conducive to the rapid transfer of electrons and electrolyte ions. Nitrogen adsorption/desorption isotherms indicate that all samples have large specific surface area (SSA) and more micropores/mesopores, which are caused by the pyrolysis of SDS at 700 ℃. MFC-SDS30 has the largest SSA (387.86 m2?g-1) and a suitable pore size distribution (3.62 nm), which effectively improve the ion diffusion mobility and shorten the ion diffusion pathways. Interestingly, the XPS results show that MFC-SDS30 has high N atom content (15.5 at.%) and O atom content (6.5 at.%) without any additional doped treatment, so the abundant pseudocapacitance is contributed through the rapid N/O atoms redox reaction. Due to the above structural characteristics, MFC-SDS30 exhibits high specific capacitance value (Csp) of 349.6 F?g-1 at 1.0 A?g-1, and the Csp (254.6 F?g-1) at 20.0 A?g-1 still maintains 73.0% of that at 1.0 A?g-1, showing good capacitive performance as electrode material for supercapacitors (SCs). The Csp of MFC-SDS30 has almost no attenuation after 15000 cycles at 10.0 A?g-1, which possesses good cycle stability. Besides, the maximum energy density of symmetrical SCs based on MFC-SDS30 is 9.2 Wh?kg-1 at the power density of 250 W?kg-1, and the energy density still reaches 4.0 Wh?kg-1 at 5000 W?kg-1, which is better than many reported carbon materials. Therefore, MF-derived porous carbon materials assisted by SDS can be a promising electrode material for SCs by means of a green and efficient method.
Key words: melamine formaldehyde resin, sodium lauryl sulfate, hierarchical porous structure, high nitrogen and oxygen content, high capacitive performance
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