Nickel Cobalt Sulfide Nanosheets Research Articles

Nickel–Cobalt Sulfide Nanosheets Anchored on Porous Carbon for Energy Storage and Small-Molecule Detection

Nickel–Cobalt Sulfide Nanosheets Anchored on Porous Carbon for Energy Storage and Small-Molecule Detection

Transition metal sulfide/oxide nanoflowers decorated on poly (aniline-2-sulfonic acid) modified polyacrylamide derived carbon cathode catalyst for bioenergy generation in microbial fuel cells

Microbial fuel cells (MFCs) are promising carbon-free energy devices with the potential to harvest power and treat wastewater simultaneously, which is crucial to meet the emerging energy challenges. Despite the high theoretical power output, the performance of MFCs is dependent on the cathodic oxygen reduction reaction (ORR) to generate electricity. Herein, a hybrid nanostructure of nickel-cobalt sulfide (NiCo2S4) nanosheets over NiCo2O4 nanoflowers on in-situ nitrogen and sulfur-doped carbon (NSC) is prepared by direct pyrolysis. Deposition of NiCo2S4 nanosheets improves the effective contact with the electrolyte and increases the catalytic sites for ORR. NiCo2S4/NiCo2O4@NSC shows an oxygen reduction peak at 0.150 V, limiting current of -0.093 mA, close to -0.107 mA for Pt/C and generates optimal power density of 831.74 mW m−2 comparable to Pt/C (857.92 mW m−2) and higher than NiCo2O4@NSC (665.86 mW m−2), NSC (650.28 mW m−2) and NC (485.98 mW m−2) air cathodes. This could be attributed to the high degree of graphitization, appropriate N and S content, a synergistic effect between the metal species and the heteroatoms, and better catalytic surface area utilization. The results suggest that M-N-S-based carbons could be potential cathodes for microbial fuel cells and similar energy devices.

Polypyrrole embedded in nickel-cobalt sulfide nanosheets grown on nickel particles passivated silicon nanowire arrays for high-performance supercapacitors

Metal sulfide-based composites have been considered as promising electrode materials for energy storage, but the fabrication process of such composites is complicated and requires a multistep hydrothermal treatment. Considering the integration with the silicon-based microelectronics, electrode materials prepared from 3D silicon and metal sulfide are needed. In this work, a hierarchical multi-shelled Ppy-NCS@Ni@SiNWs electrode was successfully developed with a simple, clean and low-cost method, where polypyrrole (Ppy) and nickel–cobalt sulfide (NCS) were co-electrodeposited on nickel particles passivated silicon nanowire arrays (SiNWs). Benefiting from the large surface of SiNWs, high conductivity of nickel passivation layer and the synergy effect between Ppy and NCS including large capacity, hydrophilic surface and high mechanical strength, the as-prepared electrode demonstrated a remarkable specific capacitance (1602 F g-1 at 1 A g−1), an excellent rate capacity (1348 F g-1 at 30 A g−1) and a high cycling stability (91.6 % of initial capacitance after 10,000 cycles). Additionally, a solid asymmetric supercapacitor was fabricated by employing Ppy-NCS@Ni@SiNWs as the positive electrode, which realized a superior energy density of 131.322 Wh kg−1 at an outstanding power density of 1.44 kW kg−1. The findings demonstrate that the hybrid composite of conductive polymer and metal sulfide grown on 3D silicon has enormous potential for energy storage materials.

Benchmarking the charge storage mechanism in nickel cobalt sulfide nanosheets anchored on carbon nanocoils/carbon nanotubes nano-hybrid for high performance supercapacitor electrode

To improve the capacity of electrodes for energy storage device, a promising architecture with enhanced electrochemical performance is extremely desired. Benefiting from the high conductivity and lower electronegativity of sulfur among chalcogens, transition metal sulfides are favorable contender of being used as an electrode material for supercapacitor device. Herein, three dimensional (3D) hybrid architecture composed of carbon nanocoils/nickel foam (CNCs/NF) substrate decorated with nickel cobalt sulfide (NiCoSx) nanosheets and carbon nanotubes (CNTs), has been fabricated via two step solvothermal reaction accompanied by vacuum filtration technique. CNTs act as conducting bridges between the porous nanosheets. The optimized CNTs/NiCoSx/CNCs/NF hybrid structure elucidates excellent specific capacitance of 3184 F g−1, outstanding capacitance retention (97.2 % after 3000 cycles) and significant capability rate (79 %). Furthermore, Density Functional Theory (DFT) calculations demonstrate that the significant capacitance enhancement in NiCoSx/CNCs originates from the enriched density of states near the Fermi level. The synergistic effect of NiCoSx anchored on CNCs/NF and CNTs is mainly responsible to significant electrochemical performance thereby achieves improved electron conductivity, increased ion diffusivity and efficacious redox reactions. Additionally, benefiting from the aforementioned properties, the CNTs/NiCoSx/CNCs/NF composite urges the researcher to use as a favorable contender for supercapacitor electrodes.

Direct decoration of carbon nanohorns with binary nickel-cobalt sulfide nanosheets towards non-enzymatic glucose sensing in human fluids

A highly controllable, green, and rapid strategy is demonstrated for fabricating of highly sensitive non-enzymatic glucose sensing platforms. Carbon nanohorns (CNHs) were decorated onto the screen-printed electrodes. Binary nickel-cobalt sulfide (NiCo-S) nanosheets (NSs) were then deposited on CNH-casted electrodes by a facile and scalable method. Following detailed structural characterization and the electrocatalytic activity of the fabricated NiCo-S/CNH electrodes towards electro-oxidation of glucose was examined in detail. The proposed electrodes operated within two distinct linear dynamic ranges of 0.001- 0.330 mM and 0.330 - 4.53 mM with sensitivities of 1842 µA.mM−1.cm−2 and 854 µA.mM−1.cm−2, respectively. Analytical sensitivity of 467 µA.mM−1.cm−2, within the linear dynamic range of 0.5 ∼ 6 mM, was obtained for the static chronoamperometric measurements. The proposed sensor showed outstanding selectivity against isostructures and co-existing interferences, long-term stability, fast response (1.7 s), excellent poisoning resistance against chloride ions, good repeatability, and high reproducibility. The structural and electrochemical properties of the NiCo-S/CNHs were also compared to its mono-metallic counterparts. Finally, to demonstrate the capability of the fabricated electrodes for glucose measurements in physiological specimens, the glucose level was successfully measured in human blood serum, urine, and saliva samples, without any sample pre-treatment.

One-step electrochemical controllable preparation of nickel cobalt sulfide nanosheets and its application in supercapacitors

The bimetallic sulfides hold great promise for achieving high-performance supercapacitors. A facile unipolar pulse electrodeposition (UPED) method is developed to prepare nickel cobalt sulfides/polypyrrole (PPy) nanocomposites on carbon paper as electrode for supercapacitors, in which the crystalline structure, morphology and electrochemical performance of Co-Ni sulfides can be readily manipulated by simply changing the Co/Ni molar ratio in the electrodeposition electrolyte. It is demonstrated that the optimal CNS-3 electrode delivers the highest specific capacitance (2004 F g−1 at 1 A g−1), excellent rate capability and superior cycling stability. The outstanding electrochemical capacitive behavior can be ascribed to the synergistic effect of the Co-Ni sulfides, the 3D integrated porous structure of the electrode, as well as the conductivity and adhesion of PPy. Furthermore, an asymmetric supercapacitor (ASC) fabricated by the CNS-3 as positive electrode and activated carbon as negative electrode also displays remarkable electrochemical performance with ultralong cycle life and high energy density. These results manifest the great potential of CNS-3 in the development of high-performance supercapacitor electrode materials. Theoretically, the green and efficient UPED technology could also allow preparing other bimetallic or polymetallic sulfides with controllable composition, crystal structure and morphology.

Construction of self-supporting bimetallic sulfide arrays as a highly efficient electrocatalyst for bifunctional electro-oxidation

Bimetal nickel–cobalt sulfide nanosheets grown on nickel foam (NCS/NF) exhibit superior OER and UOR activities with low potentials of 1.46 and 1.31 V at 10 mA cm−2, and even good activity in alkaline water electrolytes.

Flexible transparent supercapacitor with core-shell Cu@Ni@NiCoS nanofibers network electrode

Transparent flexible supercapacitors are crucial for the progress of high-tech modern transparent wearable electronic gadgets. Thus, fabricating high opto-electrochemical performance electrodes is crucial for the development of high energy density transparent flexible supercapacitors. Herein, direct growth of battery-type ternary nickel-cobalt sulfide (NiCoS) nanosheets on Cu@Ni NFs network transparent electrode forming a seamless Cu@Ni@NiCoS NFs core-shell electrode structured is reported to boost the energy density of transparent supercapacitors. The core Cu@Ni nanofibers network electrode exhibited both excellent electro-optical performance (sheet resistance ~12.19 Ω/sq at ~89% transmittance) and high mechanical flexibility. NiCoS thin nanosheets shell offer high porosity, abundant active sites, and large electrode-electrolyte contact area, thus facilitating the fast diffusion of electrolytes into active materials. The Cu@Ni@NiCoS NFs core-shell electrode demonstrated remarkable high opto-electrochemical performance (transparency of ~76.83%, an areal capacity of 6.94 μA h/cm2, and high rate capability) and excellent mechanical properties. Finally, a transparent flexible symmetric supercapacitor device (SSC device) assembled by employing Cu@Ni@NiCoS NFs as both electrodes demonstrates an outstanding energy density of 0.48 μW h/cm2 at a power density of 11.15 μW/cm2 with device transparency of ~65%.

Mesoporous Nanostructured Composite Derived from Thermal Treatment CoFe Prussian Blue Analogue Cages and Electrodeposited NiCo-S as an Efficient Electrocatalyst for an Oxygen Evolution Reaction.

Developing effective and priceless electrocatalysts is an indispensable requirement for advancing the efficiency of water splitting to get clean and sustainable fuels. Herein, we reported a feasible strategy for preparing a trimetallic (NiCoFe) superior electrocatalyst with a novel open-cage/3D frame-like structure for an oxygen evolution reaction (OER). It is prepared by consequent thermal treatments of a CoFe Prussian blue analogue frame/cage-like structure under an argon (CoFeA-TT) atmosphere and then electrochemical deposition of nickel-cobalt sulfide nanosheets as a shell layer on it. The electrochemical measurements demonstrated that the deposition of NiCo-S on CoFeA-TT (NiCo-S@CoFeA-TT) has the best catalytic performance and can drive the benchmark current density of 10 mA cm-2 at a low overpotential of 268 mV with a Tafel slope of 62 mV dec-1 and an excellent long-term catalytic stability in an alkaline medium. Its outstanding electrocatalytic performances are endowed from frame/cage-like structures, highly exposed active sites, accelerated mass and electron transport, and the synergistic effect of multiple hybrid components. The NiCo-S@CoFeA-TT showed a better performance than most advanced nonprecious catalysts and the noble commercial RuO2 catalyst. This study exhibited an effective and efficient procedure to design 3D porous architecture catalysts for the energy-relevant electrocatalysis reaction.

Construction of nickel cobalt sulfide nanosheet arrays on carbon cloth for performance-enhanced supercapacitor

Materials featured with self-supported three-dimensional network, hierarchical pores and rich electrochemical active sites are considered as promising electrodes for pseudocapacitors. Herein, a novel strategy for the growth of nickel-cobalt bisulfide (NiCoS) nanosheets arrays on carbon cloth (CC) as supercapacitor electrodes is reported, involving deposition of two-dimensional metal-organic framework (MOF) precursors on the CC skeletons, conversion of MOF into nickel-cobalt layered double-hydroxide by ion exchange process and formation of NiCoS by a sulfidation treatment. The NiCoS nanosheets with rough surface and porous structures are uniformly anchored on the CC skeletons. The unique architecture endows the composite (NiCoS/CC) with abundant accessible active sites. Besides, robust electrical/mechanical joint between the nanosheets and the substrates is attained, leading to the improved electrochemical performance. Moreover, an asymmetric supercapacitor device is constructed by using NiCoS/CC and activated carbon as a positive electrode and a negative electrode, respectively. The optimized device exhibits a high specific capacitance, large energy density and long cycle life. The NiCoS/CC electrode with intriguing electrochemical properties and mechanical flexibility holds great prospect for next-generation wearable devices.

Hierarchical nickel cobalt sulfide nanosheet arrays supported on CuO/Cu hybrid foams as a rationally designed core–shell dendrite electrocatalyst for an efficient oxygen evolution reaction

Porous nickel cobalt sulfide shells decorated on a CuO nanowire core supported on a CuO/CF hybrid foam form the unique 3D self-standing core–shell dendritic electrocatalyst of Ni–Co–S@CuO/CF for OERs, with high activity and long-term cycling cyclic stability.

Hierarchical core-shell hollow CoMoS4@Ni–Co–S nanotubes hybrid arrays as advanced electrode material for supercapacitors

Despite cobalt molybdenum sulfide (CoMoS4)-based materials are a prospective class of electrode material for supercapacitors, their relatively inferior rate capability and cyclic stability have severely restricted practical applications. Engineering multicomponent binder-free electrode material is deemed an effective approach to fulfill the demand of high-performance supercapacitors. Herein, the hierarchical core-shell hollow CoMoS4@Ni–Co–S nanotubes supported on flexible carbon cloth are designed through a scalable hydrothermal method combined with electrodeposition process. Due to the synergistic contribution of highly conductive CoMoS4 nanotubes core and highly active nickel cobalt sulfide nanosheets shell, the 3D hierarchical CoMoS4@Ni–Co–S nanotubes electrode achieves a remarkable specific capacitance of 2208.5 F g−1 at a rate of 1 A g−1 and extraordinary cycling life (91.3% capacitance retention over 5000 cycles at 3 A g−1). Moreover, the assembled CoMoS4@Ni–Co–S//activated carbon (AC) asymmetric supercapacitor presents satisfactory electrochemical performance, delivering an energy density of 49.1 W h kg−1 at a high power density of 800 W kg−1 and competitive cyclic stability (90.3% retention of initial capacity after 10000 cycles). This work designs an effective synthetic route and validates the potential prospects of binder-free 3D hierarchical architecture for developing high-performance and advanced energy storage devices.

Synthesis of porous NiCoS nanosheets with Al leaching on ordered mesoporous carbon for high-performance supercapacitors

The ordered mesoporous carbon (SBA-C) with parallel channels, synthesized using mesoporous silicon (SBA-15) as a hard template, is decorated with nanoflowers assembled by porous nickel cobalt sulfide (NiCoS) nanosheets with Al leaching through an oil bath following by a hydrothermal method. The nickel cobalt aluminum layered double hydroxide (NiCoAl LDH) precursor is successfully in-situ transformed into NiCoS nanosheets with Al leaching due to the replace of OH− and CO32− ions of the NiCoAl LDH precursor by S2− and the Kirkendall effects to etch and dissolve Al hydroxide. The NiCoS@SBA-C electrode shows surprising electrochemical performance, such as an excellent specific supercapacitance of 1757 F g−1 at a current density of 1 A g−1, superior rate capacity of 79.68% retention at 20 A g−1, and good cycling stability. An asymmetric supercapacitor (ASC) is assembled employing NiCoS@SBA-C as positive electrode and SBA-C as negative electrode, which delivers a high energy density of 38.8 Wh kg−1 at a power density of 800 W kg−1. The above results revel that incorporating ordered mesoporous carbon with transition metal sulfides is a candidate electrode material for application of energy storage devices.

Pulse reverse electrodeposited nickel cobalt sulfide nanosheets on Ni foam as battery-type electrode for battery supercapacitor hybrids

Abstract Nickel cobalt sulfide (NiaCobS) is one of promising active materials for battery supercapacitor hybrids (BSH), owing to the bimetallic nature and high electronegativity of sulfide. Electrodeposition technique is well applied to grow nanomaterials on conductive substrate since it is simple and the uniform deposition is easy to obtain. Other than normal parameters like applied potentials, currents, durations, and electrolyte compositions, the pulse reverse electrodeposition (PRE) technique is another promising way to fabricate nanomaterials on conductive substrates with repeated cathodic/anodic depositions. In this study, the PRE technique is firstly proposed to fabricate NiaCobS nanosheets on Ni foam as the battery-type electrode for BSH. The vertical grown NiaCobS nanosheet array is successfully fabricated with sizes and densities varied by applying different PRE cycles. The optimized NiaCobS electrode shows a specific capacitance (CF) of 1.75 F/cm2 at 5 mV/s, due to the suitable size and density of the nanosheet array to provide numerous active sites for generating redox reactions. This optimized electrode also presents excellent high-rate capacity with the CF retention of 65% at eight-fold scan rate and current density enhancements. At power density of 6 mW/cm2 the maximum energy density of 1.25 µWh/cm2 as well as the CF retention of 88% and Coulombic efficiency higher than 90% in 6500 times charge/discharge process are also achieved for the BSH composed of the optimized NiaCobS electrode and the activated carbon electrode.

Hierarchical nickel cobalt sulfide nanosheet on MOF-derived carbon nanowall arrays with remarkable supercapacitive performance

Nickel cobalt sulfide (CoNi2S4)-based materials have attracted extensive attention as electrodes which arise from their high theoretical capacitance, but their wide application is limited by relatively low electrical conductivity and electrochemical stability. Herein, the metal-organic framework (MOF) derived carbon nanowall arrays (CNWAs) are successfully fabricated on carbon cloth (CC) as secondary substrate, which provides more sites for electrodeposition of CoNi2S4. Furthermore, the integration of Ni layer to bridge CoNi2S4 and CNWAs, which is favorable for fast charge transfer, as well as improved conductivity. Thus, the CC/CNWAs@Ni@CoNi2S4 electrode exhibits a remarkable specific capacitance (3163 F g−1/2825 F g−1 at 1 A g−1/5 mV s−1) and rate capability (1503 F g−1/1500 F g−1 at 40 A g−1/50 mV s−1), outperforming others CoNi2S4-based electrodes reported previously. The as-prepared CC/CNWAs@Ni@CoNi2S4//commercial activated carbon asymmetric supercapacitor demonstrates superior electrochemical performance with maximum energy density of 53.8 W h kg−1 at a power density of 801 W kg−1 and long-term cycling stability with 90.1% retention after 10 000 cycles. These remarkable supercapacitive performances are attributed to the rationally hierarchical architecture, high utilization ratio of active materials and aligned ion diffusion channels of the CC/CNWAs@Ni@CoNi2S4 electrode.

Flexible hybrid yarn-shaped supercapacitors based on porous nickel cobalt sulfide nanosheet array layers on gold metalized cotton yarns

A high-performance yarn-shaped supercapacitor electrode material with light weight, small volume, flexibility and low cost, is highly desirable for the development of flexible energy storage devices. Herein, a cotton/Au/nickel cobalt sulfide hybrid yarn electrode was designed and synthesized by electrodepositing nickel cobalt sulfide nanosheet arrays on the Au metalized cotton yarn. The metalized cotton yarn as a conductive substrate ensures rapid electron transportation. The porous layer which constructed by CoNi2S4 nanosheet arrays significantly enlarges the interface between the electrolyte ions and electrode materials, providing large electroactive surface area for the faradic redox reactions. The hierarchically porous structure of entire yarn electrode shortens the electrolyte diffusion path. A synergistic effect caused by the unique electrode structure greatly increases the electrochemical performance. This hybrid yarn electrode exhibits high specific capacitance of 1323 F/g at 1 A/g, good electrochemical stability and high flexibility with performance well maintained under the mechanical bending condition. An assembled two-ply structured all-solid-state symmetric supercapacitor device delivers an energy density of 40.9 Wh/kg at a power density of 1.43 kW/kg.

Hierarchical Nickel–Cobalt Dichalcogenide Nanostructure as an Efficient Electrocatalyst for Oxygen Evolution Reaction and a Zn–Air Battery

A unique three-dimensional (3D) structure consisting of a hierarchical nickel–cobalt dichalcogenide spinel nanostructure is investigated for its electrocatalytic properties at benign neutral and alkaline pH and applied as an air cathode for practical zinc–air batteries. The results show a high oxygen evolution reaction catalytic activity of nickel–cobalt sulfide nanosheet arrays grown on carbon cloth (NiCo2S4 NS/CC) over the commercial benchmarking catalyst under both pH conditions. In particular, the NiCo2S4 NS/CC air cathode shows high discharge capacity, a narrow potential gap between discharge and charge, and superior cycle durability with reversibility, which exceeds that of commercial precious metal-based electrodes. The excellent performance of NiCo2S4 NS/CC in water electrolyzers and zinc–air batteries is mainly due to highly exposed electroactive sites with a rough surface, morphology-based advantages of nanosheet arrays, good adhesion between NiCo2S4 and the conducting carbon cloth, and the active layer formed of nickel–cobalt (oxy)hydroxides during water splitting. These results suggest that NiCo2S4 NS/CC could be a promising candidate as an efficient electrode for high-performance water electrolyzers and rechargeable zinc–air batteries.

Potentiostatic deposition of nickel cobalt sulfide nanosheet arrays as binder-free electrode for high-performance pseudocapacitor

To promote the development of supercapacitors, it is urgent to develop new class of electrode materials with low cost, high energy density and high power density. Ternary metal sulfides are one kind of promising electrode materials for high-performance energy storage devices. Here, a facile one-step potentiostatic deposition method is utilized to produce a binder-free, nanostructured NiCo2S4 electrode on FTO substrates. By controlling the Ni/Co mole ratio of the electrodepositing solution, the nanosheet-like NiCo2S4 free-standing electrode fabricated in the optimized condition exhibits a high specific capacitance of 1080 F g−1 at a current density of 1 A g−1. After 2000 cycles at 5 A g−1, there is no loss of specific capacitance, which is ascribed to the unique structure of the nanosheet arrays. These results reveal that this method can be used as a facile route to synthesize free-standing NiCo2S4 nanosheets-based electrode material of supercapacitors.

DNA-assisted synthesis of nickel cobalt sulfide nanosheets as high-performance battery-type electrode materials

Nickel-cobalt sulfide (NiCo2S4) nanosheets were successfully fabricated by an environment-friendly hydrothermal method with the assistance of DNA molecules. Different morphological samples were prepared by adjusting the concentrations of DNA. The NiCo2S4 nanosheets derived from 0.2 μg/mL DNA (denoted as DS2) exhibited a desirable mesoporous feature with superior electrochemical performance compared with other samples. As a battery-type electrode material, it exhibited a high specific capacity of 644C g−1 at the current density of 1 A/g, superior rate capability of 74.3% retention at 15 A/g and remarkable cycling stability of 90.5% after 1500 cycles. Thus, the electrode material of NiCo2S4 nanosheets assisted by DNA molecule offered great potential in eco-friendly energy storage device applications.

Highly Compressible Carbon Sponge Supercapacitor Electrode with Enhanced Performance by Growing Nickel-Cobalt Sulfide Nanosheets.

The development of compressible supercapacitor highly relies on the innovative design of electrode materials with both superior compression property and high capacitive performance. This work reports a highly compressible supercapacitor electrode which is prepared by growing electroactive NiCo2S4 (NCS) nanosheets on the compressible carbon sponge (CS). The strong adhesion of the metallic conductive NCS nanosheets to the highly porous carbon scaffolds enable the CS-NCS composite electrode to exhibit an enhanced conductivity and ideal structural integrity during repeated compression-release cycles. Accordingly, the CS-NCS composite electrode delivers a specific capacitance of 1093 F g-1 at 0.5 A g-1 and remarkable rate performance with 91% capacitance retention in the range of 0.5-20 A g-1. Capacitance performance under the strain of 60% shows that the incorporation of NCS nanosheets in CS scaffolds leads to over five times enhancement in gravimetric capacitance and 17 times enhancement in volumetric capacitance. These performances enable the CS-NCS composite to be one of the promising candidates for potential applications in compressible electrochemical energy storage devices.