title: Rational Design of Self-Supported Ni3S2Nanosheets Array for Advanced Asymmetric Supercapacitor with a Superior Energy Density.
abstract: We report a rationally designed two-step method to fabricate self-supported Ni3S2nanosheet arrays. We first used 2-methylimidazole (2-MI), an organic molecule commonly served as organic linkers in metal-organic frameworks (MOFs), to synthesize an α-Ni(OH)2nanosheet array as a precursor, followed by its hydrothermal sulfidization into Ni3S2. The resulting Ni3S2nanosheet array demonstrated superior supercapacitance properties, with a very high capacitance of about 1,000 F g-1being delivered at a high current density of 50 A g-1for 20,000 charge-discharge cycles. This performance is unparalleled by other reported nickel sulfide-based supercapacitors and is also advantageous compared to other nickel-based materials such as NiO and Ni(OH)2. An asymmetric supercapacitor was then established, exhibiting a very stable capacitance of about 200 F g-1at a high current density of 10 A g-1for 10,000 cycles and a surprisingly high energy density of 202 W h kg-1. This value is comparable to that of the lithium-ion batteries, i.e., 180 W h kg-1. The potential of the material for practical applications was evaluated by building a quasi-solid-state asymmetric supercapacitor which showed good flexibility and power output, and two of these devices connected in series were able to power up 18 green light-emitting diodes.
authors.affiliation: State Key Laboratory of Electronic Thin Films and Integrated Devices, School of Microelectronics and Solid-State Electronics, University of Electronic Science and Technology of People's Republic of China , 610054 Chengdu, People's Republic of China.|Department of Materials Science and Engineering, National University of Singapore , Singapore 117574.
authors.forename: Jun Song
authors.identifier: http://orcid.org/0000-0003-0116-8481
authors.initials: JS
authors.lastname: Chen
authors.affiliation: Department of Materials Science and Engineering, National University of Singapore , Singapore 117574.
authors.forename: Cao
authors.initials: C
authors.lastname: Guan
authors.affiliation: Department of Materials Science and Engineering, National University of Singapore , Singapore 117574.
authors.forename: Yang
authors.initials: Y
authors.lastname: Gui
authors.affiliation: Department of Materials Science and Engineering, National University of Singapore , Singapore 117574.
authors.forename: Daniel John
authors.initials: DJ
authors.lastname: Blackwood
keywords: Ni3S2; asymmetric supercapacitor; high energy density; nanosheets; self-supported