A Hollow Tube‐on‐Tube Architecture of Carbon‐Tube‐Supported Nickel Cobalt Sulfide Nanotubes for Advanced Supercapacitors

Abstract

The nanotube structure has unique advantages, such as a large electroactive surface area and shorter diffusion pathway for ions/electrons for energy storage. In this paper, we fabricated a novel supercapacitor electrode material based on a composite material with a hollow tube‐on‐tube architecture. This architecture, which was derived from the sustainable Juncus roemerianus, consisted of nickel cobalt sulfide nanotubes coating the exterior and interior of carbon tubes. The obtained hollow tube‐on‐tube structure is similar to a reservoir, in which ions/electrons can diffuse via a bi‐directional method and supply and transfer to the carbon tube interface. Consequently, this structure can probably provide more electrochemically active sites for its application in high‐performance asymmetric supercapacitors (ASCs). The assembled ASC device also presents superior specific capacitance (83 F g−1 at the current density of 0.5 A g−1), high energy density (27.7 Wh kg−1 at a power density of 263.6 W kg−1), and good cycling stability (72.23 % capacitance retention after 3000 cycles). Therefore, the NiCo2S4/bio‐carbon electrode with hollow tube‐on‐tube structure is not only a promising electrode material, but also can be applicable to energy storage and conversion devices.

Co3O4 Supraparticle‐Based Bubble Nanofiber and Bubble Nanosheet with Remarkable Electrochemical Performance

“…Based on the mass loading of the active material on both cathode and anode, the ASC exhibited a maximum energy density of 51 W h kg −1 at a power density of 800 W kg −1 (Figure f), which is comparable to, or even higher than, those of state‐of‐the‐art Co 3 O 4 ‐based ASCs . The specific energy and power densities of our ASC device are also comparable to other electrode materials reported in literatures, such as carbon tube/NiCo 2 S 4 nanotube//AC (27.7 W h kg −1 at 263.6 W kg −1 ), NiO/C‐HS//AC (30.5 W h kg −1 at 193 W kg −1 ), GQDs/MnO 2 ‐3//NG (118 W h kg −1 at 12 351 W kg −1 ), Co 3 O 4 /PANI//AC (41.5 W h kg −1 at 800 W kg −1 ), G@NiO‐1//NGH (52.6 W h kg −1 at 800 W kg −1 ), NiMoO 4 //carbon nanotube film (54.3 W h kg −1 at 4344 W kg −1 ), CuS–AC//AC (24.88 W h kg −1 at 800 W kg −1 ), NiCo 2 O 4 HNPs//AC (71 W h kg −1 at 1852 W kg −1 ), (Note: activated carbon (AC), carbon hollow spheres (C‐HS), graphene quantum dots (GQDs), nitrogen‐doped graphene (NG), polyaniline (PANI), nitrogen‐doped graphene hydrogel (NGH), HNPs) and some transition metal oxide‐ and nitride‐based supercapacitors . Because the ASC device possessed a maximum working voltage of 1.6 V with excellent energy density, both charged ASCs in series could effectively operate a red light‐emitting diode (LED) (inset of Figure f).…”

Bimetallic NiCo2S4 Nanoneedles Anchored on Mesocarbon Microbeads as Advanced Electrodes for Asymmetric Supercapacitors

“…Several advantageous features have been identified for these carbon-NCS composites, including a highly open structure based on their carbon framework, an improved electrical conductivity of the electrode, an enhanced utilization of the active material, and a reduced dissolution of active materials into electrolytes. Compared to the widely used carbon nanotubes [41][42][43][44] and graphene [45][46][47][48], mesocarbon microbead (MCMB) materials are regarded as promising carbon hosts due to their low cost and easy synthesis, which are favorable for large-scale applications. The high conductivity of MCMB is expected to enhance the overall electrical conductivity of the composite, thus resulting in an improved electron transfer during electrochemical reactions.…”

NiCo2S4‐Based Composite Materials for Supercapacitors

“…Except for graphene, other carbon materials such as the carbon nanotubes and activated carbon are also widely applied as supercapacitor electrode materials. The carbon materials store charges through EDLC mechanism . Activated carbon is porous in nature and usually has a large surface area, it can offer sufficient surface area for charge accumulation.…”