Construction of a Hierarchical NiCo₂S₄@PPy Core–Shell Heterostructure Nanotube Array on Ni Foam for a High-Performance Asymmetric Supercapacitor

Abstract

In this paper, a hierarchical NiCo2S4@polypyrrole core-shell heterostructure nanotube array on Ni foam (NiCo2S4@PPy/NF) was successfully developed as a bind-free electrode for supercapacitors. NiCo2S4@PPy-50/NF obtained under 50 s PPy electrodeposition shows a low charge-transfer resistance (0.31 Ω) and a high area specific capacitance of 9.781 F/cm(2) at a current density of 5 mA/cm(2), which is two times higher than that of pristine NiCo2S4/NF (4.255 F/cm(2)). Furthermore, an asymmetric supercapacitor was assembled using NiCo2S4@PPy-50/NF as positive electrode and activated carbon (AC) as negative electrode. The resulting NiCo2S4@PPy-50/NF//AC device exhibits a high energy density of 34.62 Wh/kg at a power density of 120.19 W/kg with good cycling performance (80.64% of the initial capacitance retention at 50 mA/cm(2) over 2500 cycles). The superior electrochemical performance can be attributed to the combined contribution of both component and unique core-shell heterostructure. The results demonstrate that the NiCo2S4@PPy-50 core-shell heterostructure nanotube array is promising as electrode material for supercapacitors in energy storage.

3D Patternable Supercapacitors from Hierarchically Architected Porous Fiber Composites for Wearable and Waterproof Energy Storage

“…As shown in Figure S4b in the Supporting Information, the peaks at 1460 and 1545 cm −1 are produced by the symmetric and antisymmetric vibrations of the pyrrole ring . The band at 1168 cm −1 is corresponding to the CN stretching vibration between two pyrrole rings, and the band at 1046 cm −1 is caused by NH in‐plane deformation vibration . All these results matched well with the literatures reported.…”

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

“…(3) The porous NiCo 2 S 4 skeleton with high conductivity builds the electrical conductive pathways for active materials leading to the enhanced conductivity and a fast reversible redox reaction. (4) The binder-free characteristic of the NiCo 2 S 4 @NiMoO 4 enables a low interfacial resistance and the absence of addictive would greatly reduce the “inactive” surface in the electrode [26, 40]. (5) The synergistic effect of the NiCo 2 S 4 nanotubes core and NiMoO 4 nanosheets shell also provides a positive effect on the capacitance.…”

“…The NiCo 2 S 4 /NF was fabricated through a two-step hydrothermal process similar to the previous reports [7, 26, 28]. Firstly, the Ni foam (1 × 4 cm) was cleaned in the HCl solution (3 mol L -1 ) and acetone then washed thoroughly using deionized (DI) water and ethanol.…”

“…And NiCo 2 S 4 as electrode has excellent electrochemical performance in energy devices [23–25]. However, many previous reports still demonstrate that most of the NiCo 2 S 4 electrodes could not meet the requirement of high capacitance [26]. To address this issue, one possible solution is to design and synthesis different morphologies of metal sulfides with a large electrochemical active surface to enhance the electrochemical behavior.…”

Ni(OH)2 Nanoflakes Supported on 3D Ni3Se2 Nanowire Array as Highly Efficient Electrodes for Asymmetric Supercapacitor and Ni/MH Battery

“…It was found that the application of array architectures with a combination of two types of materials and/or nanostructures on conducting substrates was effective approach toward improved electrochemical properties of electrodes . By these means accessible active sites, short ion transport pathways, advanced electron collection, and useful synergistic properties are created, resulting in simultaneous enhancement of capacitance, cycling stability, and rate performance . For instance, Ni(OH) 2 and other compounds, such as Co(OH) 2 , ZnCoO 4 , NiCo 2 O 4 , and Ni 3 S 2 were grown onto highly conductive supports, namely a carbon fiber paper, a 3D graphene network (3DGN) and a nickel foam (NF) to yield integrated array architectures with synergetic properties strongly expanding electrochemical performance of resulting materials.…”