title: Hierarchically porous carbon nanosheets from waste coffee grounds for supercapacitors.
abstract: The nanostructure design of porous carbon-based electrode materials is key to improving the electrochemical performance of supercapacitors. In this study, hierarchically porous carbon nanosheets (HP-CNSs) were fabricated using waste coffee grounds by in situ carbonization and activation processes using KOH. Despite the simple synthesis process, the HP-CNSs had a high aspect ratio nanostructure (∼20 nm thickness to several micrometers in lateral size), a high specific surface area of 1945.7 m(2) g(-1), numerous heteroatoms, and good electrical transport properties, as well as hierarchically porous characteristics (0.5-10 nm in size). HP-CNS-based supercapacitors showed a specific energy of 35.4 Wh kg(-1) at 11250 W kg(-1) and of 23 Wh kg(-1) for a 3 s charge/discharge current rate corresponding to a specific power of 30000 W kg(-1). Additionally, the HP-CNS supercapacitors demonstrated good cyclic performance over 5000 cycles.
authors.affiliation: Department of Polymer Science and Engineering, Inha University , Incheon 402-751, Korea.
authors.forename: Young Soo
authors.initials: YS
authors.lastname: Yun
authors.forename: Min Hong
authors.initials: MH
authors.lastname: Park
authors.forename: Sung Ju
authors.initials: SJ
authors.lastname: Hong
authors.forename: Min Eui
authors.initials: ME
authors.lastname: Lee
authors.forename: Yung Woo
authors.initials: YW
authors.lastname: Park
authors.forename: Hyoung-Joon
authors.initials: HJ
authors.lastname: Jin
keywords: carbon nanosheet; porous carbon; supercapacitor; waste coffee grounds