title: Free-standing porous carbon nanofiber/ultrathin graphite hybrid for flexible solid-state supercapacitors.
abstract: A micrometer-thin solid-state supercapacitor (SC) was assembled using two pieces of porous carbon nanofibers/ultrathin graphite (pCNFs/G) hybrid films, which were one-step synthesized by chemical vapor deposition using copper foil supported Co catalyst. The continuously ultrathin graphite sheet (∼ 25 nm) is mechanically compliant to support the pCNFs even after etching the copper foil and thus can work as both current collector and support directly with nearly ignorable fraction in a SC stack. The pCNFs are seamlessly grown on the graphite sheet with an ohmic contact between the pCNFs and the graphite sheet. Thus, the accumulated electrons/ions can duly transport from the pCNFs to graphite (current collector), which results in a high rate performance. The maximum energy density and power density based on the whole device are up to 2.4 mWh cm(-3) and 23 W cm(-3), which are even orders higher than those of the most reported electric double-layer capacitors and pseudocapacitors. Moreover, the specific capacitance of the device has 96% retention after 5000 cycles and is nearly constant at various curvatures, suggesting its wide application potential in powering wearable/miniaturized electronics.
authors.affiliation: School of Materials Science and Engineering and Tianjin Key Laboratory of Composites and Functional Materials, Tianjin University , Tianjin 300072, China.
authors.forename: Kaiqiang
authors.initials: K
authors.lastname: Qin
authors.forename: Jianli
authors.initials: J
authors.lastname: Kang
authors.forename: Jiajun
authors.initials: J
authors.lastname: Li
authors.forename: Chunsheng
authors.initials: C
authors.lastname: Shi
authors.forename: Yuxiang
authors.initials: Y
authors.lastname: Li
authors.forename: Zhijun
authors.initials: Z
authors.lastname: Qiao
authors.forename: Naiqin
authors.initials: N
authors.lastname: Zhao
keywords: chemical vapor deposition; device performance; flexible solid-state supercapacitor; porous carbon nanofiber; ultrathin graphite