Zhou Zhengping, Liu Tianyu, Khan Assad U, Liu Guoliang
Department of Chemistry, Virginia Tech, Blacksburg, VA 24061, USA.
Macromolecules Innovation Institute, Virginia Tech, Blacksburg, VA 24061, USA.
Sci Adv. 2019 Feb 1;5(2):eaau6852. doi: 10.1126/sciadv.aau6852. eCollection 2019 Feb.
Carbon fibers have high surface areas and rich functionalities for interacting with ions, molecules, and particles. However, the control over their porosity remains challenging. Conventional syntheses rely on blending polyacrylonitrile with sacrificial additives, which macrophase-separate and result in poorly controlled pores after pyrolysis. Here, we use block copolymer microphase separation, a fundamentally disparate approach to synthesizing porous carbon fibers (PCFs) with well-controlled mesopores (10 nm) and micropores (0.5 nm). Without infiltrating any carbon precursors or dopants, poly(acrylonitrile--methyl methacrylate) is directly converted to nitrogen and oxygen dual-doped PCFs. Owing to the interconnected network and the highly optimal bimodal pores, PCFs exhibit substantially reduced ion transport resistance and an ultrahigh capacitance of 66 μF cm (6.6 times that of activated carbon). The approach of using block copolymer precursors revolutionizes the synthesis of PCFs. The advanced electrochemical properties signify that PCFs represent a new platform material for electrochemical energy storage.
碳纤维具有高比表面积以及丰富的与离子、分子和颗粒相互作用的功能特性。然而，对其孔隙率的控制仍然具有挑战性。传统的合成方法依赖于将聚丙烯腈与牺牲性添加剂混合，这些添加剂会发生宏观相分离，并在热解后导致孔隙控制不佳。在此，我们采用嵌段共聚物微相分离法，这是一种从根本上不同的方法来合成具有良好控制的中孔（约10纳米）和微孔（约0.5纳米）的多孔碳纤维（PCF）。在不渗入任何碳前驱体或掺杂剂的情况下，聚（丙烯腈 - 甲基丙烯酸甲酯）直接转化为氮氧双掺杂的PCF。由于相互连接的网络结构和高度优化的双峰孔隙，PCF表现出显著降低的离子传输电阻以及66 μF cm的超高电容（是活性炭的6.6倍）。使用嵌段共聚物前驱体的方法彻底改变了PCF的合成方式。先进的电化学性能表明PCF代表了一种用于电化学储能的新型平台材料。
