Mn(OH)2-coated Ni3S2 nanosheets on Ni foam as a cathode for high-performance aqueous asymmetric supercapacitors. (July 2022)

• Record Type: Journal Article
• Authors: Song, Xiaoqiang; Emin, Adil; Chen, Yue; Yang, Mingzhe; Zou, Situo; Du, Yihe; Fu, Yujun; Li, Yali; Li, Yingtao; Li, Junshuai; He, Deyan
• Is Part Of: Journal of energy storage. Volume 51(2022)
• Publication Date: 2022-07
• Subjects: Aqueous asymmetric supercapacitors -- High performance -- Transition metal sulfide -- Transition metal hydroxide -- Electrodes; Energy storage -- Periodicals; Energy storage -- Research -- Periodicals; 621.3126
• DOI: 10.1016/j.est.2022.104513
• Languages: English
• ISSNs: 2352-152X

Abstract

Abstract: In this work, we report a high-performance self-standing electrode of Mn(OH)2 -coated Ni3 S2 (Ni3 S2 @Mn(OH)2 ) nanosheets on Ni foam by hydrothermally growing the Ni3 S2 nanosheets and electrodepositing Mn(OH)2 around Ni3 S2 . The structure of the Ni3 S2 nanosheets grown by the hydrothermal method is more stable, and the electrodeposition method is easier to synthesize Mn(OH)2 without using any binder. The electrochemical characterization demonstrates that combining the Ni3 S2 nanosheet with the Mn(OH)2 coating is an effective way to improving the charge storage performance because of the synergetic effects of both materials/structures. The electrode possesses a high area-specific capacitance of 6430.2 mF cm −2 at 1 mA cm −2 and good cycle stability with ~80.9% capacitance retention after 9000 cycles at 8 mA cm −2 . The aqueous asymmetric supercapacitors assembled with the Ni3 S2 @Mn(OH)2 cathode, the activated carbon anode and 1 M KOH electrolyte delivers an energy density of 0.371 mWh cm −2 at 0.799 mW cm −2, as well as good cycle stability with ~86.3% capacity retention after 10, 000 cycles at 20 mA cm −2 . Given the high performance and relatively simple preparation, this work provides a valuable exploration of developing high-performance cathodes for aqueous supercapacitors. Graphical abstract: A high specific capacitance of 6430.2 mF cm −2 at 1 mA cm −2 and good rate performance are delivered. Unlabelled Image Highlights: A self-standing electrode of Ni3 S2 @Mn(OH)2 was facilely prepared by the hydrothermal growth and subsequent electrodeposition. A high capacitance of 6430.2 mF cm −2 at 1 mA cm −2 is obtained. An energy density of up to 0.371 mWh cm −2 is delivered by the aqueous asymmetric supercapacitor.