Facile Synthesis of Carbon Nanosphere/NiCo2O4 Core-shell Sub-microspheres for High Performance Supercapacitor

Abstract

This paper introduced a process to prepare the carbon nanosphere (CNS)/NiCo2O4 core-shell sub-microspheres. That is: 1) CNSs were firstly prepared via a simple hydrothermal method; 2) a layer of NiCo2O4 precursor was coated on the CNS surface; 3) finally the composite was annealed at 350 °C for 2 hours in the air, and the CNS/NiCo2O4 core-shell sub-microspheres were obtained. This core-shell sub-microsphere was prepared with a simple, economical and environmental-friendly hydrothermal method, and was suitable for large-scale production, which expects a promising electrode candidate for high performance energy storage applications. Electrochemical experiments revealed that the composite exhibited remarkable electrochemical performances with high capacitance and desirable cycle life at high rates, such as: 1) the maximum specific capacitance was up to 1420 F/g at 1 A/g; 2) about 98.5% of the capacitance retained after 3000 charge-discharge cycles; 3) the capacitance retention was about 72% as the current density increase from 1 A/g to 10 A/g.

Preparation of Sandwich-like NiCo2O4/rGO/NiO Heterostructure on Nickel Foam for High-Performance Supercapacitor Electrodes

“…The peaks located at 151.6, 457.6, 455.2, 505.7, 656.6, and 1096.4 cm −1 , respectively, correspond to F 2g , E g , L O , A 1g , and 2 L O modes of NiCo 2 O 4 , while the peak located at 501.3 cm −1 belongs to NiO. These results are well consistent with the previously reported literatures [18, 21, 24].

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“…In general, EIS is usually used to investigate the performance of electrochemical capacitors, such as internal resistance and capacity [18, 19]. The EIS data were commonly analyzed by using Nyquist plots, in which the frequency response of the electrode/electrolyte system and the plots of the imaginary component ( Z ″) of the impedance against the real component ( Z ′) are presented [29].…”

“…Rationally designed electrode materials with well-defined micro-/nanostructures are attractive methods to enhance the performance of PCs [15–18]. For example, Zhang et al [15] reported Co 3 O 4 @NiCo 2 O 4 nanowire arrays for PCs with an improved specific capacitance (2.04 F cm −2 at 5 mV s −1 ) with respect to pure Co 3 O 4 .…”

Toward Aerogel Electrodes of Superior Rate Performance in Supercapacitors through Engineered Hollow Nanoparticles of NiCo2O4

“…Specifically, the peaks at 780.7 and 795.8 eV are ascribed to Co 2+ while the other two peaks at 779.4 and 794.6 eV belong to Co 3+ . Thus, the XPS results demonstrated that the electron couples of Ni 3+ /Ni 2+ and Co 3+ /Co 2+ coexisted in NiCo 2 O 4 aerogel, which is consistent with the previously reported results for NiCo 2 O 4 10. The C 1s emission spectrum (Figure 3d) can be divided into four peaks centered at 284.6, 286.4, 287.8, and 289.0 eV, which is attributed to the C—C/C=C, C—O, C=O, and O=C—O groups,6 respectively.…”

Rose flower-like NiCo2O4 with hierarchically porous structures for highly reversible lithium storage

“…Compared with other counterparts, transition metal oxides with nanostructural characteristics attracted wide attention due to their high surface-to-volume ratio and short path length for Li-ion diffusion [7][8][9]. Among transition metal oxides, cobalt oxide exhibited capacity 3 times higher than that of conventional graphite, but considering the high cost and toxic nature of cobalt, it has not been regarded as a suitable alternative anode material [10][11][12][13] [14][15][16][17][18]. With two different metal cations, these binary metal oxides exhibit high electrochemical characteristics due to their complicate chemical composition and synergic effects of multiple metal species.…”