NiCo2S4@NiMoO4 Core-Shell Heterostructure Nanotube Arrays Grown on Ni Foam as a Binder-Free Electrode Displayed High Electrochemical Performance with High Capacity

Abstract

Core-shell-structured system has been proved as one of the best architecture for clean energy products owing to its inherited superiorities from both the core and the shell part, which can provide better conductivity and high surface area. Herein, a hierarchical core-shell NiCo2S4@NiMoO4 heterostructure nanotube array on Ni foam (NF) (NiCo2S4@NiMoO4/NF) has been successfully fabricated. Because of its novel heterostructure, the capacitive performance has been enhanced. A specific capacitance up to 2006 F g-1 was obtained at a current density of 5 mA cm-2, which was far higher than that of pristine NiCo2S4 nanotube arrays (about 1264 F g-1). More importantly, NiCo2S4@NiMoO4/NF and active carbon (AC) were congregated as positive electrode and negative electrode in an asymmetric supercapacitor. As-fabricated NiCo2S4@NiMoO4/NF//AC device has a good cyclic behavior with 78% capacitance retention over 2000 cycles, and exhibits a high energy density of 21.4 Wh kg-1 and power density of 58 W kg-1 at 2 mA cm-2. As displayed, the NiCo2S4@NiMoO4/NF core-shell herterostructure holds great promise for supercapacitors in energy storage.Electronic supplementary materialThe online version of this article (doi:10.1186/s11671-017-2180-z) contains supplementary material, which is available to authorized users.

Highly Energetic and Stable Gadolinium/Bismuth Molybdate with a Fast Reactive Species, Redox Mechanism of Aqueous Electrolyte

“…The molybdenum (Mo) species from Bi 2 MoO 6 does not contribute to the redox reaction but enhances the electrical conductivity, which ultimately leads to improved performance characteristics of the host structure. 52 A very similar profile is also evident from the corresponding charge−discharge plots shown in Figure 9B. At a lower current density (4 mA cm −2 ), a discharge plateau-like profile in the −0.6 region is visible, but it has shortened at higher current densities.…”

“…Given this fact, the clear occurrence of a redox peak even at a higher scan rate of 20 mV s –1 (Figure A) indicates efficient charge transfer relating to the adsorption behavior of OH – ions in the Bi 2 MoO 6 electrode. The molybdenum (Mo) species from Bi 2 MoO 6 does not contribute to the redox reaction but enhances the electrical conductivity, which ultimately leads to improved performance characteristics of the host structure . A very similar profile is also evident from the corresponding charge–discharge plots shown in Figure B.…”

Zn Metal Atom Doping on the Surface Plane of One-Dimesional NiMoO4 Nanorods with Improved Redox Chemistry

“…Hence, the redox peak observed in Figure 10 refers to the oxidation and reduction of the Ni 2+ ion. 42,43 A vital piece of information that we get from CVs (Figure 10A) is that the current density as well as the area under the curve for the Zn-doped composite is comparatively higher than that of the pristine sample. This suggests that Zn nanoparticles in the active material enhanced the electrochemical activity of NiMoO 4 .…”

Hydrothermal Synthesized of CoMoO4 Microspheres as Excellent Electrode Material for Supercapacitor

“…Among them, the metal molybdates have attracted much attention for energy storage application. Such as NiMoO 4 [ 19 – 21 ], MnMoO 4 [ 22 , 23 ], CoMoO 4 [ 6 , 8 , 11 , 24 , 25 ] and other metal molybdates have been extensively investigated as excellent electrode materials for supercapacitor. As reported in Refs.…”