Synthesis and supercapacitance of flower-like Co(OH)2 hierarchical superstructures self-assembled by mesoporous nanobelts

Abstract

A facile hydrothermal strategy was first proposed to synthesize flower-like Co(OH) 2 hierarchical microspheres. Further physical characterizations revealed that the flower-like Co(OH) 2 microspherical superstructures were self-assembled by one-dimension nanobelts with rich mesopores. Electrochemical performance of the flower-like Co(OH) 2 hierarchical superstructures were investigated by cyclic voltammgoram, galvanostatic charge-discharge and electrochemical impedance spectroscopy in 3 M KOH aqueous electrolyte. Electrochemical data indicated that the flower-like Co(OH) 2 superstructures delivered a specific capacitance of 434 Fg −1 at 10 mA cm −2 (about 1.33 Ag −1 ), and even kept it as high as 365 Fg −1 at about 5.33 Ag −1 . Furthermore, the SC degradation of about 8% after 1,500 continuous charge-discharge cycles at 5.33 Ag −1 demonstrates their good electrochemical stability at large current densities.

Pine needle β-Co(OH)2 grown on Ni foam substrate for high specific capacitance and good cycling stability as advanced electrochemical pseudocapacitor materials

“…3(f). The high-frequency intersection of the plots at the real axis represents the internal solution resistance including the electrolyte resistance, the collector/electrode contact resistance, and the electrode/electrolyte interface resistance [2]. b-Co(OH) 2 /NF is smaller than that of b-Co(OH) 2 .…”

“…Cobalt hydroxide has been attracting much attention for energy storage applications due to its high theoretical specific capacitance [1][2][3][4]. For example, Gong et al [5] prepared Co(OH) 2 sheets via a ball-milling method, whose average specific capacitance was 599 F/g at a scan rate of 2 mV/s.…”

Cobalt-based compounds and composites as electrode materials for high-performance electrochemical capacitors

“…[194][195][196] Zhang and co-workers developed biomolecule-assisted hydrothermal processes to synthesize different Co(OH) 2 mesocrystals and nano-superstructures. [194][195][196] When lysine was used, three-dimensional urchin-like b-Co(OH) 2 microspheres were obtained. 193 The oriented nanowires in a radial form created abundant V-shape porous channels.…”

“…Flowerlike b-Co(OH) 2 hierarchical superstructures self-assembled from mesoporous ($3 nm) nanobelts were synthesized when Co(SO 4 ) 2 $6H 2 O was used as the cobalt precursor. 196 When L-arginine was used as a hydrolysis-controlling agent, 195 a-Co(OH) 2 triangular nanosheets with a thickness of $10 nm (Fig. 4) were synthesized.…”

“…The specic capacitance of the binder and additive-free a-Co(OH) 2 electrode was $643 F g À1 . 196 4.2.2 Electrochemical deposition. [199][200][201][202][203][204][205][206][207][208][209][210] Gupta et al 199 fabricated a-Co(OH) 2 nanosheets on stainless steel by cathodic potentiostatic deposition.…”