title: Low-cost superior solid-state symmetric supercapacitors based on hematite nanocrystals.
abstract: We present a facile method for the fabrication of hematite nanocrystal-carbon cloth (Fe2O3-CC) composite. Hierarchical manganite is chosen as the sacrificial precursor, that does not contribute to the component of final iron oxide but can be in situ dissolved by the acid produced from the Fe3+hydrolysis. This method effectively enhances the specific surface area and conductivity of hematite (Fe2O3) by attaching Fe2O3nanocrystals (around 5 nm) firmly on the surface of carbon fibers. The obtained Fe2O3-CC can be directly used as a binder-free electrode for a supercapacitor. Interestingly, the composite electrode exhibits synergistic electrochemical capacitance (electrochemical double-layer capacitance and pseudo-capacitance). It manifests a very high areal capacitance of 1.66 F cm-2(1660 F g-1) at 2 mA cm-2and excellent cycling performance at large current densities (88.6% retention at 30 mA cm-2after 5000 cycles) in a three-electrode testing system, which is among the best performances reported in the literature. Importantly, when fabricated as a solid-state flexible symmetric supercapacitor it still shows a maximum energy density of 8.74 mW h cm-3and power density of 253.9 mW cm-3. Additionally, its good flexibility makes it suitable for portable devices.
authors.affiliation: Key Laboratory of Clean Chemistry Technology of Guangdong Regular Higher Education Institutions, School of Chemical Engineering and Light Industry, Guangdong University of Technology, Guangzhou 510006, People's Republic of China.
authors.forename: Shaomin
authors.initials: S
authors.lastname: Peng
authors.forename: Lin
authors.initials: L
authors.lastname: Yu
authors.forename: Bang
authors.initials: B
authors.lastname: Lan
authors.forename: Ming
authors.initials: M
authors.lastname: Sun
authors.forename: Gao
authors.initials: G
authors.lastname: Cheng
authors.forename: Shuhuan
authors.initials: S
authors.lastname: Liao
authors.forename: Han
authors.initials: H
authors.lastname: Cao
authors.forename: Yulin
authors.initials: Y
authors.lastname: Deng