Rational Construction of Hollow Core‐Branch CoSe2 Nanoarrays for High‐Performance Asymmetric Supercapacitor and Efficient Oxygen Evolution. Issue 5 (18th December 2017)

• Record Type: Journal Article
• Authors: Chen, Tian; Li, Songzhan; Wen, Jian; Gui, Pengbin; Guo, Yaxiong; Guan, Cao; Liu, Jinping; Fang, Guojia
• Is Part Of: Small. Volume 14:Issue 5(2018)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2017-12-18
• Subjects: CoSe2 -- oxygen evolution reaction -- reaction mechanism -- selenization reaction -- supercapacitor; Nanotechnology -- Periodicals; Nanoparticles -- Periodicals; Microtechnology -- Periodicals; 620.5
• DOI: 10.1002/smll.201700979
• Languages: English
• ISSNs: 1613-6810

Abstract

Abstract: Metal selenides have great potential for electrochemical energy storage, but are relatively scarce investigated. Herein, a novel hollow core‐branch CoSe2 nanoarray on carbon cloth is designed by a facile selenization reaction of predesigned CoO nanocones. And the electrochemical reaction mechanism of CoSe2 in supercapacitor is studied in detail for the first time. Compared with CoO, the hollow core‐branch CoSe2 has both larger specific surface area and higher electrical conductivity. When tested as a supercapacitor positive electrode, the CoSe2 delivers a high specific capacitance of 759.5 F g −1 at 1 mA cm −2, which is much larger than that of CoO nanocones (319.5 F g −1 ). In addition, the CoSe2 electrode exhibits excellent cycling stability in that a capacitance retention of 94.5% can be maintained after 5000 charge–discharge cycles at 5 mA cm −2 . An asymmetric supercapacitor using the CoSe2 as cathode and an N‐doped carbon nanowall as anode is further assembled, which show a high energy density of 32.2 Wh kg −1 at a power density of 1914.7 W kg −1, and maintains 24.9 Wh kg −1 when power density increased to 7354.8 W kg −1 . Moreover, the CoSe2 electrode also exhibits better oxygen evolution reaction activity than that of CoO. Abstract : CoSe2 nanoarrays with a novel hollow core‐branch structure on carbon cloth are synthesized by a facile selenization reaction of predesigned CoO nanocones. The CoSe2 demonstrates good properties both in supercapacitor and in oxygen evolution reaction applications. The outstanding electrochemical performance of synthesized CoSe2 is attributed to its unique structure, excellent electrical conductivity, and high activity of Se atoms.