title: A two-step etching route to ultrathin carbon nanosheets for high performance electrical double layer capacitors.
abstract: Two-dimensional (2D) carbon materials have attracted intense research interest for electrical double layer capacitors (EDLCs) due to their high aspect ratio and large surface area. Herein, we propose an exfoliation-chlorination route for preparing ultrathin carbon nanosheets by using ternary layered carbide Ti3AlC2 as the precursor. Due to the large intersheet space of exfoliated layered carbide (MXene), the as-prepared carbon nanosheets exhibit a thickness of 3-4 nm and a large specific surface area of 1766 m(2) g(-1) with hierarchical porosity. These features significantly improve the ion-accessible surface area for charge storage and shorten the ion transport length in the thin dimension. As a result, the carbon nanosheets show a high specific capacitance (220 F g(-1) at 0.5 A g(-1)), remarkable high power capability (79% capacitance retention at 20 A g(-1)) when measured in a symmetrical two-electrode configuration in an aqueous electrolyte. The method described in this work provides a new route to prepare 2D electrode materials from a bulk precursor, thus exploiting their full potential for EDLCs.
authors.affiliation: Jiangsu Key Laboratory of Materials and Technology for Energy Conversion, College of Material Science and Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing, 210016, P. R. China. dh_msc@nuaa.edu.cn azhangxg@nuaa.edu.cn.
authors.forename: Bing
authors.initials: B
authors.lastname: Ding
authors.forename: Jie
authors.initials: J
authors.lastname: Wang
authors.forename: Ya
authors.initials: Y
authors.lastname: Wang
authors.forename: Zhi
authors.initials: Z
authors.lastname: Chang
authors.forename: Gang
authors.initials: G
authors.lastname: Pang
authors.forename: Hui
authors.initials: H
authors.lastname: Dou
authors.forename: Xiaogang
authors.initials: X
authors.lastname: Zhang