Zhang Dongdong, He Chong, Zhao Jianghong, Wang Jianlong, Li Kaixi
Institute of Coal Chemistry, Chinese Academy of Sciences, 27 Taoyuan South Road, Taiyuan 030001, China; Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 010049, China.
Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 010049, China.
J Colloid Interface Sci. 2019 Jun 15;546:101-112. doi: 10.1016/j.jcis.2019.03.059. Epub 2019 Mar 19.
Mesoporous carbons attract increasing attention owing to their potential applications in supercapacitors. So far, controlled synthesis of mesoporous carbons with a narrow pore size distribution relies largely on the complicated template methods. To avoid the use of templates, a surfactant-free emulsion polymerization method is presented for the fabrication of a melamine-modified phenolic resin microrod (MPRR) assembled by micron-sized spherical cells and thin walls. In addition, one-step KOH activation strategy is adopted to synthesize hierarchical mesoporous activated carbon with 2-10 nm narrow mesopores by using MPRR as carbon precursors. The as-prepared mesoporous activated carbon has a high specific surface area of about 2758 m g and a mesopore volume of 0.54 cm g (calculated by density functional theory), comprising ∼43.5% of total pore volume (∼1.43 cm g). Hierarchical mesopores can significantly accelerate ion transfer and increase micropore accessibility, which endow the carbon with high specific capacitance equal to 409 F g at 0.1 A g and 268 F g at 100 A g in 6 M KOH electrolyte, with a high capacitance retention of 66%. Moreover, the assembled symmetric supercapacitor also exhibits good cycling stability in KOH electrolyte and delivers high power density equal to 12080 W kg when energy density is 5.02 Wh kg. This finding provides an insight into directional tailoring of mesoporous structures of phenolic resin-based carbon materials at the molecular level for high-performance supercapacitors.
介孔碳因其在超级电容器中的潜在应用而受到越来越多的关注。到目前为止，孔径分布狭窄的介孔碳的可控合成在很大程度上依赖于复杂的模板法。为避免使用模板，本文提出了一种无表面活性剂乳液聚合法，用于制备由微米级球形单元和薄壁组装而成的三聚氰胺改性酚醛树脂微棒（MPRR）。此外，采用一步KOH活化策略，以MPRR为碳前驱体，合成了具有2-10nm窄介孔的分级介孔活性炭。所制备的介孔活性炭具有约2758m²/g的高比表面积和0.54cm³/g的介孔体积（由密度泛函理论计算），占总孔体积（约1.43cm³/g）的约43.5%。分级介孔可以显著加速离子转移并增加微孔可及性，这赋予该碳在6M KOH电解液中0.1A/g时409F/g和100A/g时268F/g的高比电容，电容保持率高达66%。此外，组装的对称超级电容器在KOH电解液中也表现出良好的循环稳定性，当能量密度为5.02Wh/kg时，功率密度高达12080W/kg。这一发现为在分子水平上定向剪裁基于酚醛树脂的碳材料的介孔结构以制备高性能超级电容器提供了思路。
