Kim Seongseop, Ju Mieun, Lee Jisung, Hwang Jongkook, Lee Jinwoo
Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Daejeon 34141, Republic of Korea.
Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), 77 Cheongam-ro, Nam-gu, Pohang 37673, Gyeongbuk, Republic of Korea.
J Am Chem Soc. 2020 May 20;142(20):9250-9257. doi: 10.1021/jacs.0c00311. Epub 2020 Feb 21.
Two-dimensional (2D) carbon nanosheets with micro- and/or mesopores have attracted great attention due to unique physical and chemical properties, but well-defined nanoporous carbon nanosheets with tunable thickness and pore size have been rarely realized. Here, we develop a polymer-polymer interfacial self-assembly strategy to achieve hierarchically porous carbon nanosheets (HNCNSs) by integrating the migration behaviors of immiscible ternary polymers with block copolymer (BCP)-directed self-assembly. The balanced interfacial compatibility of BCP allows the migration of a BCP-rich phase to the interface between two immiscible homopolymer major phases (i.e., homopoly(methyl methacrylate) and homopolystyrene), where the BCP-rich phase spreads thinly to a thickness of a few nanometers to decrease the interfacial tension. BCP-directed coassembly with organic-inorganic precursors constructs an ordered mesostructure. Carbonization and chemical etching yield ultrathin HNCNSs with hierarchical micropores and mesopores. This approach enables facile control over the thickness (5.6-75 nm) and mesopore size (25-46 nm). As an anode material in a potassium ion battery, HNCNSs show high specific capacity (178 mA h g at a current density of 1 A g) with excellent long-term stability (2000 cycles), by exploiting the advantages of the hierarchical pores and 2D nanosheet morphology (efficient ion/electron diffusion) and of the large interlayer spacing (stable ion insertion).
具有微孔和/或介孔的二维（2D）碳纳米片因其独特的物理和化学性质而备受关注，但具有可调厚度和孔径的明确纳米多孔碳纳米片却很少实现。在此，我们开发了一种聚合物-聚合物界面自组装策略，通过将不混溶的三元聚合物的迁移行为与嵌段共聚物（BCP）导向的自组装相结合，来制备分级多孔碳纳米片（HNCNSs）。BCP的平衡界面相容性使得富含BCP的相迁移到两个不混溶的均聚物主相（即聚（甲基丙烯酸甲酯）和聚苯乙烯）之间的界面，在该界面处富含BCP的相 thinly 铺展至几纳米的厚度以降低界面张力。BCP与有机-无机前驱体的导向共组装构建了有序的介观结构。碳化和化学蚀刻产生具有分级微孔和介孔的超薄HNCNSs。这种方法能够轻松控制厚度（5.6 - 75 nm）和介孔尺寸（25 - 46 nm）。作为钾离子电池的负极材料，HNCNSs通过利用分级孔结构和二维纳米片形态（高效的离子/电子扩散）以及大层间距（稳定的离子插入）的优势，在1 A g的电流密度下表现出高比容量（178 mA h g）和出色的长期稳定性（2000次循环）。
