A versatile ionic liquid-assisted approach to synthesize hierarchical structures of β-Ni(OH)2 nanosheets for high performance pseudocapacitor. (10th January 2016)

• Record Type: Journal Article
• Authors: Chen, Jun Song; Gui, Yang; Blackwood, Daniel John
• Is Part Of: Electrochimica acta. Volume 188(2016)
• Page Start: 863
• Page End: 870
• Publication Date: 2016-01-10
• Subjects: Pseudocapacitor -- Hierarchical structures -- β-Ni(OH)2 -- Nanosheets -- Ionic Liquid; Electrochemistry -- Periodicals; Electrochemistry, Industrial -- Periodicals; 541.37
• DOI: 10.1016/j.electacta.2015.12.029
• Languages: English
• ISSNs: 0013-4686

Abstract

Graphical abstract: In this work, we demonstrated a versatile ionic liquid-assisted synthesis of various hierarchical structures composed of β-Ni(OH)2 nanosheets with different nickel salt precursors. When the film samples were tested as electrode materials for supercapacitors, the one prepared using nickel acetate demonstrated the best electrochemical performance. The impedance analysis suggests that such a performance could be explained by the greatly facilitated charge transfer into the Ni(OH)2 film and the accelerated subsequent transport processes through the film. Abstract: This work describes a versatile hydrothermal approach to synthesize different types of hierarchical structures composed of single crystalline β-Ni(OH)2 nanosheets. We use the ionic liquid (IL) 1-butyl-3-methylimidazolium chloride (BmimCl) as a structure directing agent, which allows the formation of films consisting of β-Ni(OH)2 nanosheets on the nickel foam substrate. It is found that the IL not only controls the formation of the sheet-like structure, but also promotes the growth of the nanosheets on the substrate, building an intimate contact between the active hydroxide film and the conducting metal foam. This IL agent is so effective that such a hierarchical film can also be obtained with different thickness and organization if different nickel salt precursor is used. When these film samples were applied as the electrode materials for pseudocapacitor, they exhibited promising capacitive properties with a high capacitance of about 700 F g −1 even at a high charge-discharge current rate of 5 A g −1 for prolonged cycling.