Carbon-nanoparticles encapsulated in hollow nickel oxides for supercapacitor application

Abstract

Monodisperse carbon nanoparticles encapsulated in hollow NiO nanostructures (C@NiO) have been successfully synthesized by calcination from a Ni(OH) 2 covered carbon (C@Ni(OH) 2 ) precursor. The as-prepared products at each stage were extensively characterized and carefully discussed. The electrochemical properties of the carbon encapsulated in hollow NiO nanostructures were investigated using cycling voltammetry and charge-discharge techniques. The specific capacitance of the obtained C@NiO electrode was about 988.7 F g À1 at a current density of 0.5 A g À1 . It shows better performance than hollow NiO spheres obtained in oxygen atmosphere. Furthermore, the C@NiO electrode shows a good capacitive retention of ca. 90.7% after 1000 charge-discharge cycles.

3D hierarchical mesoporous roselike NiO nanosheets for high-performance supercapacitor electrodes

“…Figure 4b shows CV curves at various scan rates for prepared 3D hierarchical mesoporous roselike NiO nanosheets electrode materials in 6 M KOH electrolyte in the voltage range of -0.2-0.45 V. With the increasing scan rate, the anodic peaks move toward higher potential and the cathodic peaks move toward lower potential at the same time, which may be attributed to the increasing electric polarization and irreversible reactions as the scan rate scales up [24] . Besides, in Figure 4b, it can be seen that there scarcely any contribution from double-layer capacitance compared with the faradaic pseudo-capacitance which contributes a great proportion [25] .…”

Preparation and electrochemical characteristic of porous NiO supported by sulfonated graphene for supercapacitors

“…Furthermore, the high resistivity of NiO is another drawback for practical applications as pseudocapacitor materials [13]. To address the above problem, carbonaceous materials with high electrical conductivity and fair ductility have been introduced to suppress the aggregation of metal oxides particles, and thus improve their pseudocapacitive behaviors [14][15][16][17][18]. Following the rise of graphene, NiO/graphene composites serve as candidate materials for supercapacitors.…”

Hierarchically nanostructured transition metal oxides for supercapacitors

“…Thus, considerable efforts have been made to enhance the SC performance by creating composites of TMOs and carbon materials, such as TMOs/graphene and TMOs/ carbon nanofibers (CFs) [154][155][156][157][158][159][160][161][162][163][164][165][166][167]. The synthesized multi-component composites can maximize the benefits from all components [154][155][156][157][158][159][160][161][162][163][164][165][166][167][168][169].…”