Low-cost superior solid-state symmetric supercapacitors based on hematite nanocrystals. (22nd November 2016)

• Record Type: Journal Article
• Authors: Peng, Shaomin; Yu, Lin; Lan, Bang; Sun, Ming; Cheng, Gao; Liao, Shuhuan; Cao, Han; Deng, Yulin
• Is Part Of: Nanotechnology. Volume 27:Number 50(2016)
• Publication Date: 2016-11-22
• Subjects: hematite nanocrystal -- hierarchical manganite -- solid state -- symmetric supercapacitor; Nanotechnology -- Periodicals; Nanotechnology -- Periodicals; Nanotechnology; Publications périodiques; Nanotechnologies; Periodicals; 620.5
• DOI: 10.1088/0957-4484/27/50/505404
• Languages: English
• ISSNs: 0957-4484

Abstract

Abstract: We present a facile method for the fabrication of hematite nanocrystal–carbon cloth (Fe2 O3 –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 Fe 3+ hydrolysis. This method effectively enhances the specific surface area and conductivity of hematite (Fe2 O3 ) by attaching Fe2 O3 nanocrystals (around 5 nm) firmly on the surface of carbon fibers. The obtained Fe2 O3 –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 −2 and excellent cycling performance at large current densities (88.6% retention at 30 mA cm −2 after 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 −3 and power density of 253.9 mW cm −3 . Additionally, its good flexibility makes it suitable for portable devices.