Enhancing performance of NiCo2S4/Ni3S2 supercapacitor electrode by Mn doping

Engineering NiCo2S4 nanoparticles anchored on carbon nanotubes as superior energy-storage materials for supercapacitors

Fabricating high-capacity electrode materials toward supercapacitors has attracted increasing attention. Here we report a three-dimensional CNTs/NiCo2S4 nanocomposite material synthesized successfully by a facile one-step hydrothermal technique. As expected, a CNTs/NiCo2S4 electrode shows remarkable capacitive properties with a high specific capacitance of 890 C g-1 at 1 A g-1. It also demonstrates excellent cycle stability with an 83.5% capacitance retention rate after 5000 cycles at 10 A g-1. Importantly, when assembled into a asymmetric supercapacitor, it exhibits a high energy density (43.3 W h kg-1) and power density (800 W kg-1). The exceptional electrochemical capacity is attributed to the structural features, refined grains, and enhanced conductivity. The above results indicate that CNTs/NiCo2S4 composite electrode materials have great potential application in energy-storage devices.

Ternary Nanohybrid of Ni3S2/CoMoS4/MnO2 on Nickel Foam for Aqueous and Solid-State High-Performance Supercapacitors

To overcome the issues related to supercapacitor (SC) electrodes, such as high cost, low specific capacitance (C_s), low energy density (ED), requirements for expensive binder, etc., binderless electrodes are highly desirable. Here, a new ternary nanohybrid is presented as a binder-free SC electrode based on Ni₃S₂, CoMoS₄, and MnO₂. A facile two-step hydrothermal route, followed by a short thermal annealing process, is developed to grow amorphous polyhedral structured CoMoS₄ and further wrap MnO₂ nanowires on Ni foam. This rationally designed binder-free electrode exhibited the highest C_s of 2021 F g⁻¹ (specific capacity of 883.8 C g⁻¹ or 245.5 mAh g⁻¹) at a current density of 1 A g⁻¹ in 1 M KOH electrolyte with a highly porous surface morphology. This electrode material exhibited excellent cycling stability (90% capacitance retention after 4000 cycles) due to the synergistic contribution of individual components and advanced surface properties. Furthermore, an aqueous binder-free asymmetric SC based on this ternary composite exhibited an ED of 20.7 Wh kg⁻¹, whereas a solid-state asymmetric SC achieved an ED of 13.8 Wh kg⁻¹. This nanohybrid can be considered a promising binder-free electrode for both aqueous and solid-state asymmetric SCs with these remarkable electrochemical properties.

Fabrication of three-dimensional WO3 nanotube bundles on carbon cloth as a binder-free electrode for high-performance supercapacitors

The WO3 nanotube bundles are fabricated on carbon cloth, exhibiting high specific capacitance, low charge transfer resistance, and excellent stability.

Facile In Situ Synthesis of Co(OH)2-Ni3S2 Nanowires on Ni Foam for Use in High-Energy-Density Supercapacitors

Ni3S2 nanowires were synthesized in situ using a one-pot hydrothermal reaction on Ni foam (NF) for use in supercapacitors as a positive electrode, and various contents (0.3-0.6 mmol) of Co(OH)2 shells were coated onto the surfaces of the Ni3S2 nanowire cores to improve the electrochemical properties. The Ni3S2 nanowires were uniformly formed on the smooth NF surface, and the Co(OH)2 shell was formed on the Ni3S2 nanowire surface. By direct NF participation as a reactant without adding any other Ni source, Ni3S2 was formed more closely to the NF surface, and the Co(OH)2 shell suppressed the loss of active material during charging-discharging, yielding excellent electrochemical properties. The Co(OH)2-Ni3S2/Ni electrode produced using 0.5 mmol Co(OH)2 (Co0.5-Ni3S2/Ni) exhibited a high specific capacitance of 1837 F g-1 (16.07 F cm-2) at a current density of 5 mA cm-2, and maintained a capacitance of 583 F g-1 (16.07 F cm-2) at a much higher current density of 50 mA cm-2. An asymmetric supercapacitor (ASC) with Co(OH)2-Ni3S2 and active carbon displayed a high-power density of 1036 kW kg-1 at an energy density of 43 W h kg-1 with good cycling stability, indicating its suitability for use in energy storage applications. Thus, the newly developed core-shell structure, Co(OH)2-Ni3S2, was shown to be efficient at improving the electrochemical performance.

Novel heterostructure Cu2S/Ni3S2 coral-like nanoarrays on Ni foam to enhance hydrogen evolution reaction in alkaline media

We fabricated a heterostructure Cu2S/Ni3S2 nanosheet array, which can accelerate charge transfer and provide more active sites. This work provides a promising non-noble metal electrocatalyst for water splitting under alkaline conditions.

High specific energy supercapacitor electrode prepared from MnS/Ni3S2 composite grown on nickel foam

Herein, MnS was prepared in situ with Ni3S2 directly on nickel foam to obtain a novel binder-free highly conductive electrode with a superb echinocactus-like morphology.