Cobalt Sulfide Research Articles

Design of thin-layer porous nickel cobalt sulfide for high-performance asymmetric supercapacitors

Design of thin-layer porous nickel cobalt sulfide for high-performance asymmetric supercapacitors

Three dimensional hollow sulphide nanocomposites for supercapacitor electrodes

The transition metal sulphides have gained sufficient attraction due to their high theoretical capacitance, low electronegativity, good thermal and electrical conductivity and good redox behaviour. In the present work, nanocomposites of nickel cobalt sulphide (NiCoS), zinc cobalt sulphide (ZnCoS), copper cobalt sulphide (CuCoS) and nickel-zinc-copper cobalt sulphide (NiZnCuCoS) have been prepared, by hydrothermal synthesis method, for their use as the supercapacitor electrode material. The X-ray diffraction analysis, Field Emission Scanning Electron Microscopy images and UV–Visible studies suggest the formation of quantum dots (as the crystallite size is in the range of 3.5 nm–6.0 nm) in all the nanocomposites. The aim of this study is to observe the change in the electrochemical properties of the transition metal sulphides by multi-metal doping. The electrochemical measurements reveal that among all the prepared nanocomposites, highest specific capacitance (150 F g−1 at 5 mV s−1) has been exhibited by CuCoS nanocomposites (nanowires like structure) whereas highest potential window (1.7 V) and hence highest energy density (16.5 W h kg−1 at 0.1 A g−1) has been exhibited by NiZnCuCoS nanocomposites. Presently, the main goal of supercapacitors is to provide high energy density. It is observed that multi-metal sulphides (NiZnCuCoS), when used as the supercapacitor electrode, provide better electrochemical performance which may be owing to the specific nanosheets like structures as well as good synergism between Ni, Zn, Cu and Co transition metals. Hence it is observed that by multi-metal doping, the supercapacitive behaviour of transition metal sulphides has improved.

Growth of AgCoS@CNTs composite on nickel foam to enrich the redox active sites for battery-supercapacitor hybrid energy storage device

Supercapacitors are recognized as reliable energy storage technologies, despite obstacles such as inadequate energy density and comparatively small capacitance. In this study, we employed a hydrothermal synthesis method to fabricate silver cobalt sulfide (AgCoS) and doped it with carbon nanotubes (CNTs). The surface area of 19.35 m2/g was achieved with AgCoS@CNT//AC using BET measurements. The galvanostatic charge-discharge (GCD) measurements revealed a specific capacity of 1023 C/g for AgCoS@CNT. To construct an asymmetric device (AgCoS@CNT//AC), the best-performing AgCoS@CNT composite was employed as the positive electrode, while activated carbon (AC) served as the negative electrode. The specific capacity of the asymmetric device AgCoS@CNT//AC was measured to be 104 C/g, accompanied by a high power density of 750 W/kg and an impressive energy density of 32 Wh/kg. Notably, the columbic efficiency of the AgCoS@CNT//AC device reached 100% after 5000 consecutive cycles, while maintaining a capacity retention of 82%. These findings indicate that the AgCoS@CNT composite might serve as an intriguing material as an electrodes for supercapacitor applications.

One-step magneto-solvothermal synthesis of porous network NiCo2S4 for high-performance supercapacitors

A simple one-step magneto-solvothermal method is developed to prepare three-dimensional porous network nickel cobalt sulfide (NiCo2S4) as electrodes for supercapacitors, resulting in excellent electrochemical performance. By taking advantage of the modulation of the microscopic morphology by the magnetic fields, NiCo2S4 electrodes exhibit high specific capacitance (605.8 C/g at 1 A/g) and excellent rate capability (80% remained capacitance after 3000 charge–discharge cycles at a current density of 10 A/g) because of significant increase in the exposure of the active sites. Moreover, hybrid supercapacitors fabricated by NiCo2S4 prepared under a magnetic field of 3 T as the positive electrode and carbon electrode (activated carbon) as the negative electrode demonstrate a high energy density of 22.65 Wh/kg at the power density of 750.14 W/kg and excellent cycling stability. This work provides a novel route to improve the electrochemical performances of NiCo2S4 using magneto-solvothermal method.

Unveiling the performance of hydrothermally synthesized transition metal sulfide with polyaniline composite for hybrid supercapacitor applications

Hybrid supercapacitors (SCs) have acquired astonishing features and being recognized as prospective energy storage devices for energy applications. Herein this work, we describe the hydrothermal synthesis of cobalt sulfide and the polymerization of aniline to prepare polyaniline (PANI). Initially, each electrode was tested in three electrode setup in which the CoS/PANI composite showed high electrochemical performance compared to pristine sample. Furthermore, CoS/PANI was studied along with activated carbon (AC) to explore the hybrid SCs application of the prepared composite. In two electrode arrangement, the hybrid device has achieved a remarkable Qs of 123.6 C g-1 at 0.2 A g−1, energy 29.2 Wh kg−1 as well as high specific power 1275 W kg-1. The hybrid SCs also displayed a maximum capacity retain value of 86.4% after 5000 GCD cycles. These results show that the CoS/PANI can be utilized as a best electrode material for the contemporary energy storage devices.

Multifunctional microwave absorption materials of multiscale cobalt sulfide/diatoms co-doped carbon aerogel

Microwave absorption materials (MAMs) have attracted much attention for their potential applications in stealth technology and prevention of electromagnetic pollution problems. Multifunctional MAMs are highly demanded because they can be applied in harsh environments. Hence, based on multiscale manipulation of atomic engineering, nanostructure and microstructure, a multiscale hollow cobalt sulfide/diatoms co-doped carbon aerogel was preparedthrough the physical crosslinking of divalent ions, unidirectional freezing, kirkendall effect, and heteroatomic doping. The aerogel with a low density of 13.1 mg/mm3 has a unique “lamellar-pillar” network structure due to the growth of ice crystals during the preparation process. With the assistance of thiourea, the doping of N, S atoms and the construction of hollow cobalt sulfide are accomplished simultaneously. The ingenious integration facilitates the synergistic effect of conductive loss, defect polarization, interfacial polarization, and multiple scattering. The multiscale hollow cobalt sulfide/diatoms co-doped carbon aerogel had a maximum reflection loss of −51.96 dB and an effective absorption bandwidth of 6.4 GHz, which is higher than that of other reported MAMs. It is further verified through finite element simulation and experiments that the aerogel has an excellent microwave absorption properties. In addition, the aerogel has excellent thermal insulation and flame retardant properties. Therefore, the development of this aerogel can help to use MAMs in complex applications.

Fabrication of CuCo2S4 on composite interface materials made of polypyrrole and nitrogen-doped carbon nanotubes for use in supercapacitors

Due to their low cost, high conductivity, and synergistic impact, the ternary CuCo2S4 sulfides were thoroughly examined in this article as electrode materials for electrochemical properties. The hydrothermal reaction process for energy storage application was aided by the nanostructured copper cobalt sulfides (CuCo2S4) secured on multiwalled carbon nanotubes/polypyrrole composite via ultrasonication. By utilizing a 6 M KOH electrolyte, the produced composite electrode displays increased specific capacitances and cyclic stability. The structural, morphological, and surface properties of the composite materials were analyzed using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Energy-dispersive X-ray spectroscopy (EDS), X-ray photo electron spectroscopy (XPS), Field emission scanning electron microscopy (FE-SEM), the Brunauer-Emmett-Teller (BET) theory, and the Barrett, Joyner, For better supercapacitor use, the morphological characteristics of nanoscale CuCo2S4 on NMWCNT/PPy surface were confirmed. The synthesized CuCo2S4@NMWCNT and CuCo2S4@NMWCNT/PPy composite electrodes shown outstanding cyclic stability up to 5000 cycles and specific capacitances of 259 F/g, respectively, at 1 A/g. The synthesized ternary composite electrode's electrochemical impedance spectroscopy (EIS) characteristics reveal the lowest Rs (0.53 and 0.63) and charge transfer resistance (Rct) as 65.6 Ω, as well as reasonably outstanding retention of 90.5 % after 5000 cycles. Through the use of a three-electrode configuration, the increased surface and morphological features of the CuCo2S4 on NMWCNT/PPy composite boosted the electrochemical properties of the ternary composite electrode.

Tailing copper cobalt sulfide particle-decorated tube-like structure as efficient active material of battery supercapacitor hybrid

Copper cobalt sulfide (CuCo2S4) has received intensive attentions as one of effective battery-type materials of battery supercapacitor hybrids (BSH), because of numerous redox states and large conductivity. Morphology has been widely reported to play important roles on energy storage ability. Tube-like structure is beneficial for providing large surface area at inner/outer surface, and efficient charge transfer paths in one-dimensional directions. In this study, the CuCo2S4 particle-decorated tube-like structure is firstly designed on nickel foam via the hydrothermal process at different temperatures. The effects on morphology, composition and electrochemical performance are examined. The CuCo2S4 synthesized at 160 °C shows the most uniform rod size and regularly distributed particles on surface. The highest specific capacitance (CF) of 831.7 F/g corresponding to the capacity of 115.6 mAh/g is achieved for the optimal CuCo2S4 electrode, due to the largest electrochemical surface area with multiple active sites. A BSH is fabricated by using the CuCo2S4 positive electrode and the activated carbon negative electrode. A wide potential window of 1.5 V and the maximum energy density of 32.1 Wh/kg at power density of 1.1 kW/kg are achieved. The CF retention of 78.8% and Coulombic efficiency of 95.5% are also attained after 10,000 charge/discharge cycles for the BSH.

In situ growth of bimetallic nickel cobalt sulfide (NiCo2S4) nanowire arrays encapsulated by nitrogen-doped carbon on carbon cloth as binder-free and flexible electrode for high-performance aqueous Zn batteries

In situ growth of bimetallic nickel cobalt sulfide (NiCo2S4) nanowire arrays encapsulated by nitrogen-doped carbon on carbon cloth as binder-free and flexible electrode for high-performance aqueous Zn batteries

Exchanging Anion in CuCo-Carbonate Double Hydroxide for Faradaic Supercapacitors: A Case Study.

A systematic synthetic method involving the anion exchange process was designed and developed to fabricate the superior functioning three-dimensional (3-D) urchin-architectured copper cobalt oxide (CuCo2O4; CCO) and copper cobalt sulfide (CuCo2S4; CCS) electrode materials from copper-cobalt carbonate double hydroxide [(CuCo)2(CO3)(OH)2; CCH]. The effective tuning of chemical, crystalline, and morphological properties was achieved during the derivatization process of CCH, based on the anion exchange effect and phase transformation without altering the 3-D spatial assembly. Benefiting from morphological and structural advantages, CCO and CCS exhibited superior electrochemical activity with capacity values of 1508 and 2502 C g-1 at 10 A g-1 to CCH (1182 C g-1 at 10 A g-1). The thermal treatment of CCH has generated a highly porous nature in nanospikes of 3-D urchin CCO structures, which purveys betterment in electrochemical phenomena than pristine smooth-surfaced CCH. Meanwhile, the sulfurization reaction induced the anion effect to a greater extent in the CCS morphology, resulting in hierarchical 3-D urchins formed by 1-D nanospikes constituting coaxially swirled 2-D nanosheets with high exposure of active sites, specific surface areas, and 3-D electron/ion transportation channels. The asymmetric supercapacitor was constructed with a superior CCS electrode as a cathode and an activated carbon electrode as an anode, showing a high specific capacity of 287.35 C g-1 at 7 A g-1 and durability for 5000 cycles with 94.2% retention at a high current density of 30 A g-1. The ultrahigh energy and power density of 135.3 W h kg-1 (10 A g-1) and 44.35 kW kg-1 (30 A g-1) were harvested during the PC device performance. Our finding proposes an idea about the importance of anions and phase transformation as a versatile tool for engineering high-functioning electrode materials and their endeavor toward overwhelming the major demerit of SCs by aggrandizing the energy density value and rate performance.

High performance electro-active artificial muscles based on 3D dendritic nickel cobalt sulfide nanorods-graphene electrodes

As the desire for biomimicry that utilizes the advantages of natural organisms, increases, electroactive artificial muscles, an emerging technology, have been phasing-in to bioinspired applications in medicine, electronics, and soft robotics. However, it remains challenging to simultaneously obtain stable response characteristics and high bending displacement, considering the instability of electrode materials in open air environments. Here, 3D dendritic nickel cobalt sulfide nanorods grown on graphene electrodes, exhibiting stable electrochemical reactivity owing to their structural and material advantages, are employed to realize high-performance artificial muscles. Importantly, the significant influence of the phase transition of nickel-cobalt metals and graphene template in the synthesis steps on tuning the electrical and electrochemical properties is reported. The resulting artificial muscles show an almost 98 % enhanced bending performance and stable response to both AC and DC input signals without significant phase delay or distortion. These substantial improvements in the performance of artificial muscles enable the demonstration of bioinspired soft locomotive robots; these artificial muscles will thus expand the soft electronics industry in the field of next-generation human-machine interfaces.

Development of ultra-thin and high-efficient bi-layer microwave absorbers from Fe3N@C and CoS2 samples

Nowadays, electromagnetic interference (EMI) is one of the pollution that harm human health and electronic devices. Iron nitride (Fe3N) and cobalt sulfide (CoS2) are promising microwave-absorbing materials (MAMs) due to their intriguing properties. In this work, polygonal Fe3[email protected] and flower-like CoS2 were fabricated, and Fe3[email protected] showed pretty good magnetic properties. Microwave absorption properties of as-prepared samples were investigated, where Fe3[email protected] and CoS2 reached minimum reflection loss (RL) of −12 dB and −23 dB, respectively. In addition, Fe3[email protected] mostly had no effective absorption bandwidth (EAB), whereas Co2S was 2.5 GHz. The better microwave absorption properties of CoS2 compared to Fe3[email protected] could be explained through the combination of electrical conductivity, C0 values, loss capacity matching, impedance matching, and attenuation constant. It is worth mentioning that both Fe3[email protected] and CoS2 could not be considered promising MAMs. Therefore, RL curves of bi-layer MAMs made from as-prepared samples were simulated, where CoS2 and Fe3[email protected] acted as absorption and matching layers, respectively. The simulated Fe3[email protected]/CoS2 = 0.6 mm/0.6 mm bi-layer absorber could reach an RL of −45 dB and an EAB of 13 GHz, which was superior to the single-layer ones. The fabricated Fe3[email protected]/CoS2 = 0.6 mm/0.6 mm bi-layer absorber confirmed these excellent properties, which could be a result of the enhancement of complex permittivity, complex permeability, dielectric, and magnetic loss tangents.

Engineered exosome-mediated cobalt sulfide quantum dot targeted delivery for photothermal and chemodynamic anticancer therapy

Engineered exosome-mediated cobalt sulfide quantum dot targeted delivery for photothermal and chemodynamic anticancer therapy

Hollow porous carbon nanospheres containing polar cobalt sulfide (Co9S8) nanocrystals as electrocatalytic interlayers for the reutilization of polysulfide in lithium–sulfur batteries

HypothesisThe introduction of functional interlayers for efficient anchoring of lithium polysulfides has received significant attention worldwide. ExperimentsA facile wet-chemical method was adopted to obtain hollow porous carbon nanospheres (HPCNSs) impregnated with metallic and polar cobalt sulfide (Co9S8) nanocrystals (abbreviated as “Co9S8@HPCNS”). The prepared nanocrystals were employed as electrocatalytic interlayers via separator coating for the efficient capture and reutilization of polysulfide species in Li-S batteries. The HPCNSs were synthesized via the polymerization method followed by carbonization and template removal. The Co9S8 nanocrystals were impregnated inside the HPCNSs, followed by heat treatment in a reducing atmosphere. FindingsThe porous structure of the CNS enables the efficient percolation of the electrolyte, in addition to accommodating unwanted volume fluctuations during redox processes. Furthermore, the metallic Co9S8 nanocrystals improve the electronic conductivity and enhance the polarity of the CNS towards the polysulfide. Correspondingly, the Li–S cells featuring Co9S8@HPCNS as electrocatalytic interlayers and regular sulfur (S) electrodes display improved electrochemical performance such as reasonable rate performance and prolonged cycling stability at different current rates (0.1, 0.5, and 1.0 C). Therefore, we anticipate that the rational design strategy proposed herein will provide significant insights into the synthesis of advanced materials for various energy storage applications.

Amorphous low-coordinated cobalt sulphide nanosheet electrode for electrochemically synthesizing hydrogen peroxide in acid media

This study investigates in-depth the local atomic environment-property relationship of amorphous low-coordination catalysts toward the 2e− oxygen reduction reaction (ORR). Here, an ethanol-assisted slow nucleation strategy was adopted to flexibly regulate the intrinsic activity of CoSx nanostructures for efficient 2e− ORR by oriented control the coordination number of Co. When Co and S form Co-S4 coordination structures, the CuNW@CoS4 exhibits an ultra-low overpotential (0.018 V) with 93 % H2O2 selectivity, and 91 % Faraday efficiency in acidic media at 0.1 VRHE. Furthermore, thus produced H2O2 satisfies in-situ organic pollutants degradation by electro-Fenton. XAS and DFT calculations unveil the S-induced forming of abundant low-coordinated Co atoms as active sites in Co-S4, validating that a favorable d-band energy level of Co center can weaken the OOH* adsorption for accelerating the H2O2 production kinetics. This work is anticipated to enlighten the rational design of high-performance ORR catalysts for practically feasible H2O2 electrosynthesis toward wastewater remediation.

Tuning nickel cobalt sulfides embedded in hierarchical porous carbon nanosheets/carbon nanotubes interpenetrating frameworks by in situ bimetallic MOF-derived engineering towards exceptional lithium storage

A Ni/Co-MOF-engaged bimetallic nickel cobalt sulfide nanoparticles encapsulating into a 3D interpenetrating hierarchical porous ultrathin carbon nanosheets/carbon nanotubes framework (NiCo2S4 @HPCS/CNTs) have been designed and fabricated via carbonization under the reducing atmosphere and further sulfurization processes. The in situ development of extruded CNTs from organic ligands in MOF templates is autocatalyzed by the metal nanoparticles created during the reduction process. Intriguingly, MOFs serve as periodically atom-dispersed self-sacrificial templates for the in situ formation of hierarchical porous carbon-encapsulated micro/nano heterostructure materials. NiCo2S4 nanocrystals are uniformly dispersed into the 1D CNTs/2D carbon nanosheets/3D carbon spheres conductive networks in this special compositional and hierarchical structure, effectively inhibiting volume expansion, enhancing the electronic conductivity, and further enabling ultrafast lithium ion diffusion kinetics. When used as anode materials of lithium-ion battery (LIB), the NiCo2S4 @HPCS/CNTs electrode delivers outstanding cycling stability with capacity retention of 782.4 mAh g−1 after 800 cycles at 1 A g−1 and excellent rate capability of 584.9 mAh g−1 at a high current density of 4 A g−1. This study provides a novel approach for preparing multi-metallic sulfide generated from MOF precursors with surprisingly heterostructures as the advanced anode materials for LIBs.

Enhanced Electrochemical Performance of Metallic CoS-Based Supercapacitor by Cathodic Exfoliation.

Two-dimensional nanomaterials hold great promise as electrode materials for the construction of excellent electrochemical energy storage and transformation apparatuses. In the study, metallic layered cobalt sulfide was, firstly, applied to the area of energy storage as a supercapacitor electrode. By a facile and scalable method for cathodic electrochemical exfoliation, metallic layered cobalt sulfide bulk can be exfoliated into high-quality and few-layered nanosheets with size distributions in the micrometer scale range and thickness in the order of several nanometers. With a two-dimensional thin sheet structure of metallic cobalt sulfide nanosheets, not only was a larger active surface area created, but also, the insertion/extraction of ions in the procedure of charge and discharge were enhanced. The exfoliated cobalt sulfide was applied as a supercapacitor electrode with obvious improvement compared with the original sample, and the specific capacitance increased from 307 F∙g-1 to 450 F∙g-1 at the current density of 1 A∙g-1. The capacitance retention rate of exfoliated cobalt sulfide enlarged to 84.7% from the original 81.9% of unexfoliated samples while the current density multiplied by 5 times. Moreover, a button-type asymmetric supercapacitor assembled using exfoliated cobalt sulfide as the positive electrode exhibits a maximum specific energy of 9.4 Wh∙kg-1 at the specific power of 1520 W∙kg-1.

Facile synthesis of copper cobalt sulfide and nickel hydroxide tube-like composites as battery-type active material of energy storage devices

Bimetallic sulfide has attracted much attentions as efficient electroactive materials of battery supercapacitor hybrid (BSH), because of numerous redox states, high conductivity and good energy efficiency. Developing composites having excellent chemical and electrochemical properties is necessary to enhance the energy storage features of bimetallic sulfides. In this study, CuCo2S4 and Ni(OH)2 composites (CuCo2S4@Ni(OH)2) are designed on Ni foam via the facial hydrothermal process and chemical bath deposition as the electroactive material of BSH at first time. Effects of Ni(OH)2 amounts on CuCo2S4 on electrochemical and physical properties of CuCo2S4@Ni(OH)2 are investigated. The physical mixed CuCo2S4 and Ni(OH)2 composite is also fabricated to verify synergistic effects of CuCo2S4@Ni(OH)2. A higher specific capacitance (CF) of 1583.9 F/g along with the capacity of 220.0 mAh/g are got for optimal CuCo2S4@Ni(OH)2 electrode, respectively comparing to 831.7 and 1063.3 F/g of CuCoS4 and Ni(OH)2 electrodes. A BSH is fabricated by the CuCo2S4@Ni(OH)2 electrode and the activated carbon electrode. The potential window of 1.6 V and maximum energy density of 32.1 Wh/kg at 1.1 kW/kg are achieved. The CF retention of 78% and Coulombic efficiency higher than 97% in 8000 charge/discharge cycles are also obtained for this BSH.

Hierarchical phosphorus-oxygen incorporated cobalt sulfide hollow micro/nano-reactor for highly-efficient electrocatalytic overall water splitting

Transition metal sulfides have always been the promising electrocatalysts for overall water splitting. The regulation of electronic structure and accessibility of active sites are helpful to further boost their electrochemical performance from the aspect of thermodynamics and kinetics, respectively. Herein, we put forward an advanced multi-ion regulation strategy coupled with the morphology management strategy to prepare high performance electrocatalyst with low overpotential and high solar-to-hydrogen STH efficiency. Therefore, a hierarchical nanosheets stacked phosphorus-oxygen incorporated cobalt sulfide (Co-OSP) hollow micro/nano-reactor was designed and synthesized. The experimental results and theoretical calculations indicate that reasonably modulated phosphorus and oxygen extent render the electrocatalyst with optimal conductivity, electron structure and adsorption/desorption behavior of intermediates. In addition, the finite element analysis (FEA) results show that the unique morphology endows the electrocatalyst with fast mass diffusion/transfer pathway and much more accessible active sites. As a consequence, the Co-OSP hollow sphere achieves excellent electrocatalytic water splitting performance with overpotentials as low as 175.3 and 132.7 mV for OER and HER in 1.0 M KOH alkaline solution, respectively. When applied in silicon-based photovoltaic-electrochemical (PV-EC) system, Co-OSP electrodes realizes as high as 9.8 % STH efficiency with cell voltage of 1.48 V. This work presents a potential application in electrocatalysis, lithium batteries, solar cells and other energy-related fields that require catalysts with large exposed surface area and controllable local electric fields. The facile preparation processes and abundant raw materials reserve could increase the commercial viability.

Electrodeposited Heterostructures of Cobalt Sulfide/Molybdenum Sulfide Trigger both Acidic and Alkaline HER

MoS2 has attracted significant attention as a non-platinum group electrocatalyst for the hydrogen evolution reaction (HER). There have been extensive efforts demonstrating that by doping MoS2 with various transition metals, such as Co, the HER activity of the catalyst is enhanced. In particular, this work has shown that various cobalt sulfide phases can act as a co-catalyst with MoS2. Here, we report on the electrodeposition of a c-CoSx/MoS2 heterostructure catalyst for the HER reaction in both acidic and alkaline conditions. Using Raman spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction, and scanning electron microscopy, it is demonstrated that depending on the precursor concentrations, various morphologies, grain size, and c-CoSx phases can be achieved, all of which have an impact on the activity and stability of the c-CoSx/MoS2 catalysts. The most promising catalyst composition demonstrated excellent stability in both acidic and alkaline conditions with low overpotentials to reach 10 mA cm−2 of 112 mV and 60 mV and with Tafel slopes of 113 mV dec−1 and 81 mV dec−1, respectively. This report demonstrates that the c-CoSx/MoS2 heterostructure is one of the most catalytically active materials for HER, especially in alkaline conditions.