A high-performance hybrid supercapacitor with NiO derived NiO@Ni-MOF composite electrodes

Quaternary Cu2FeSnS4/PVP/rGO Composite for Supercapacitor Applications

Electrochemical energy storage is a current research area to address energy challenges of the modern world. The Cu2FeSnS4/PVP/rGO-decorated nanocomposite using PVP as the surface ligand was explored in a simple one-step solvothermal route, for studying their electrochemical behavior by designing asymmetric hybrid supercapacitor devices. The full cell three-electrode arrangements delivered 748 C/g (62.36 mA h/g) at 5 mV/s employing CV and 328 F/g (45.55 mA h/g) at 0.5 A/g employing GCD for the Cu2FeSnS4/PVP/rGO electrode. The half-cell two-electrode device can endow with 73 W h/kg and 749 W/kg at 1 A/g energy and power density. Furthermore, two Cu2FeSnS4/PVP/rGO//AC asymmetric devices connected in series for illuminating a commercial red LED more than 1 min were explored. This work focuses the potential use of transition-metal chalcogenide composite and introduces a new material for designing high-performance supercapacitor applications.

Structural, Morphological, and Electrochemical Performance of CeO2/NiO Nanocomposite for Supercapacitor Applications

The composite of ceria has been widely studied as an electrode material for supercapacitors applications due to its high energy density. Herein, we synthesize CeO2/NiO nanocomposite via a hydrothermal route and explore its different aspects using various characterization techniques. The crystal structure is investigated using X-ray diffraction, Fourier transform infrared, and Raman spectroscopy. The formation of nanoflakes which combine to form flower-like morphology is observed from scanning electron microscope images. Selected area scans confirm the presence of all elements in accordance with their stoichiometric amount and thus authenticate the elemental purity. Polycrystalline nature with crystallite size 8–10 nm having truncated octahedron shape is confirmed from tunneling electron microscope images. Using X-ray photoelectron spectroscopy the different oxidation states of Ce and Ni are observed which play the role of active sites in the electrochemical performance of this nanocomposite material. Cyclic Voltammetry(CV) measurements at different scan rates and Galvanic Charge Discharge (GCD) measurements at different current densities are performed to probe the electrochemical response which revealed the potential of CeO2/NiO nanocomposite as an electrode material for energy storage devices.

The Application of Metal-Organic Frameworks and Their Derivatives for Supercapacitors

Supercapacitors (SCs), one of the most popular types of energy-storage devices, present lots of advantages, such as large power density and fast charge/discharge capability. Being the promising SCs electrode materials, metal-organic frameworks (MOFs) and their derivatives have gained ever-increasing attention due to their large specific surface area, controllable porous structure and rich diversity. Herein, the recent development of MOFs-based materials and their application in SCs as the electrode are reviewed and summarized. The preparation method, the morphology of the materials and the electrical performance of various MOFs and their derivatives (such as carbon, metal oxide/hydroxide and metal sulfide) are briefly discussed. Most of recent works concentrate on Ni-, Co- and Mn-MOFs and their composites/derivatives. Conclusions and our outlook for the researches are also given, which would be a valuable guideline for the rational design of MOFs materials for SCs in the near future.

Hybrid structured CoNi2S4/Ni3S2 nanowires with multifunctional performance for hybrid capacitor electrodes and overall water splitting

Rational design of electrode materials plays a significant role in potential applications such as energy storage and conversion. In this work, CoNi₂S₄/Ni₃S₂ nanowires grown on Ni foam were synthesized through a facile hydrothermal approach, revealing a large capacitance of 997.2 F g⁻¹ and cycling stability with 80.3% capacitance retention after 5000 cycles. The device was prepared using CoNi₂S₄/Ni₃S₂//AC as the positive electrode and active carbon as the negative electrode, and delivered an energy density of 0.4 mW h cm⁻³ at a power density of 3.99 mW cm⁻³ and an excellent cycle life with 79.2% capacitance retention after 10 000 cycles. In addition, the hybrid CoNi₂S₄/Ni₃S₂ nanowires demonstrate excellent OER performance with low overpotential of 360 mV at 30 mA cm⁻² and overpotential of 173.8 mV at −10 mA cm⁻² for the HER, a cell voltage of 1.43 V, and excellent cycle stability.

Rational design of electrode materials plays a significant role in potential applications such as energy storage and conversion.

In-situ coating TiO2 surface by plant-inspired tannic acid for fabrication of thin film nanocomposite nanofiltration membranes toward enhanced separation and antibacterial performance

A major issue hindering development of thin film nanocomposite (TFN) nanofiltration (NF) membrane is the interfacial defects induced by nanomaterial aggregation in top layer. Although various nanomaterials surface modification strategies have been developed to eliminate the interfacial defects, they usually involve extra modification steps and complex post-treatments. Inspired by the substrate-independent coating ability of tannic acid (TA) and the fact that the phenolic hydroxyl groups in TA can react with acyl chloride group in trimesoyl chloride, a TA coating solution containing TiO₂ nanoparticles was used as an aqueous phase of interfacial polymerization to prepare interfacial modified TFN NF membranes in this study. Surface modification of TiO₂ nanoparticles and interfacial polymerization can be carried out in a single step without any extra pre-modification step. It was found that the TA coating on TiO₂ nanoparticles surface could decrease TiO₂ aggregations and enhance interfacial compatibility between TiO₂ and polyester matrix. The TFN NF membrane prepared at a TiO₂ loading of 0.020 wt% exhibited a pure water flux of 28.8 L m^-2 h^-1 (284% higher than that of the controlled TFC membrane), and possessed enhanced NaCl and Na₂SO₄ rejections of 57.9% and 94.6%, respectively, breaking through the trade-off between permeability and selectivity.

Rationally designed Ni2P/Ni/C as a positive electrode for high-performance hybrid supercapacitors

Ni₂P/Ni/C is fabricated a simple simultaneous carbonization and phosphidation process. It displays exceptional rate performance with excellent cycling ability, mainly resulting from accelerated charge transfer ability and stable porous structure.

Effects of electrodeposition time on a manganese dioxide supercapacitor

As is well known that the specific capacitance of supercapacitors cannot be improved by increasing the mass of the deposited MnO₂ films, which means an appropriate deposition duration is important. In this study, nanobelt-structured MnO₂ films were prepared by the electrochemical deposition method under different deposition time to explore the effects of electrodeposition time change on the microstructure and electrochemical properties of this material. Benefiting from the microstructure of the MnO₂ films, the transfer properties of the charged electrons and ions were promoted. Meanwhile, a 3D porous nickel foam was chosen as the deposition substrate, which rendered an enhancement of the MnO₂ conductivity and the mass of the active material. The enhanced specific capacitance and specific surface area attributed to synergistic reactions. Subsequently, the electrochemical performances of the as-prepared materials were analyzed via cyclic voltammetry (CV), galvanostatic charge–discharge (GCD) and electrochemical impedance spectroscopy (EIS) tests. Results show that the optimum sample deposited for 50 s has a specific capacitance of 291.9 F g⁻¹ at the current density of 1 A g⁻¹ and lowest R_ct. However, its electrochemical stability cannot come up to the level of the 300 s sample due to the microstructure change.

As is well known that the specific capacitance of supercapacitors cannot be improved by increasing the mass of the deposited MnO₂ films, which means an appropriate deposition duration is important.

Green synthesis of ZnO–Co3O4 nanocomposite using facile foliar fuel and investigation of its electrochemical behaviour for supercapacitors

Currently, the sustainable fabrication of supercapacitors with enhanced properties is one of the significant research hotspots.