Electrode Material For Hybrid Supercapacitors Research Articles

Metal-organic frameworks and composites on their basis: structure, synthesis methods, electrochemical properties and application prospects (a review)

Various types of metal-organic frameworks (MOF) and their structural parameters have been reviewed and their classification has been presented. Most widely used synthesis methods and approaches for MOF and composites on their basis have been discussed. MOF structure is a regular 3D lattice formed by organic linkers and metallic clusters. It has been shown for an example of literary data on MOF synthesis and structural studies that the types of bonds and metals can strongly affect the spatial structure and dimensions of MOF crystals: they can have nano-, micro- and meso-dimensions, be dense or porous, bulk or layered. This variety of structural parameters determines the wide range of their properties and potential applications. Prospects and methods of controlling the shapes of the crystals, their size and spatial bonds between organic components and metal ions have been reviewed. Major attention has been paid to zeolite-like frameworks (ZIF) as the most promising ones from the viewpoint of structure, synthesis and electrochemical current source applications. Discussion has touched on possible modifications and methods of controlling the properties of those MOFs and composites on their basis and introduction of impurities, including those having magnetic properties. Possible synthesis options of complex composites through controlled MOF pyrolysis have been presented, for either small-batch or scalable processes. The effect of heat treatment conditions on the final properties and electrochemical applications of those materials has been demonstrated. ZIF-67 structured MOF doping with one more metal has been presented as variant of modifying the properties of MOF and composites on their basis. For example, the Authors have implemented cobalt MOF synthesis wherein cobalt is partially substituted for manganese at the synthesis stage. Furthermore, a simple water solution co-deposition synthesis technique has been modified with ultrasonication thus reducing the time consumption of the process. Electrochemical studies have shown that the unit electrochemical capacity of pyrolyzed MOF electrodes with partial cobalt substitution for manganese is appreciably higher as compared to the manganese-free materials. The unit capacity and energy density increase with manganese content in the MOF. MOF manganese doping delivers a considerable improvement in the electrochemical parameters of the electrode materials for hybrid supercapacitors on their basis (from 100 to 298 F/g at 0.25 A/g current density). The results suggest that cobalt substitution for manganese is an effective method of improving the electrochemical parameters of MOFs. It has been demonstrated that the development of new approaches to the design of MOF based composite materials and the study of the physicochemical regularities of their interaction with various carriers is an important task.

Hydrothermally synthesized CuNiS@CNTs composite electrode material for hybrid supercapacitors and non-enzymatic electrochemical glucose sensor

Hydrothermally synthesized CuNiS@CNTs composite electrode material for hybrid supercapacitors and non-enzymatic electrochemical glucose sensor

Polypyrrole and activated carbon enriched MnCo2O4 ternary composite as efficient electrode material for hybrid supercapacitors.

The development of proficient electrode materials is one of the major tasks faced by modern techniques for energy storage. Integrating different materials with synergistic effects can be a valuable strategy for designing storage devices with high capacity and energy density. The spinel manganese cobaltite (MnCo2O4) is an outstanding candidate for supercapacitors owing to its remarkable pseudocapacitive behavior. However, it suffers from low electric conductivity and limited cyclic stability. To overcome its limitations, activated carbon with superior cyclic stability and polypyrrole with high electric conductivity can be incorporated in MnCo2O4. The synergistic effect of these components offers high capacitance, better conductivity, and superior cyclic performance to the ternary composite. Herein, the MnCo2O4/AC/PPY ternary composite has been synthesized by a facile approach. The optimized ternary composite (MAP-20) exhibited a wonderful capacitance of 945.77 F g-1 at five mV s-1 compared to pristine MnCo2O4 (254.98 F g-1). The real-time applicability of the optimized composite was tested with asymmetric device configuration. The asymmetric device with MAP-20 and MnO2/AC electrodes exhibited a wonderful Ed of 88.12 W h kg-1 (Pd ∼ 1.6 kW kg-1). The asymmetric device also exhibited excellent cyclic performance of 89.68% for 10 000 cycles. Further, the real-time applicability of the device was tested by illuminating a 39 red LED panel. Three asymmetric cells connected in series illuminated the panel for about 45 minutes. All these results suggest that the synergistic integration of various efficient electrode materials leads to enhanced electrochemical performance of supercapacitors.

Two-dimensional tungsten oxide nanoflakes grafted over g-C3N4 as excellent electrode materials for hybrid supercapacitors

This paper presents the successful design of nanocomposites comprising metal oxide modification over graphitic carbon nitride (g-C3N4) applicable as efficient electrode materials for hybrid supercapacitors. Two-dimensional tungsten oxide (WO3) nanoflakes were synthesized with an acid-assisted precipitation method followed by hydrothermal treatment. Nanocomposite WO3/g-C3N4 has been reported as specially designed electrode materials for supercapacitors where nano WO3 grafted over g-C3N4 nanosheets by in-situ chemical co-precipitation method. Various structural and electrochemical analyses were performed to investigate the overall morphological dependency of the charge storage phenomenon. The synthesized WO3/g-C3N4 nanocomposites exhibit superior specific capacitance of 1051.43 Fg−1 at 1 Ag−1, having a capacity retaining of 85.1 % performed at 10 Ag−1 after 10,000 cycles. However, the fabricated asymmetric supercapacitor has achieved an energy density of 114.75 Whkg−1 at 8.5 kWkg−1 power density. The combination enhancement of energy density with notable cycle stability of WO3/g-C3N4 than WO3 and g-C3N4 nanosheets are accredited to the excellent structural, thermal, and electrochemical stability possessed by the heterostructure WO3/g-C3N4 and thus proposing a promising electrode material for hybrid supercapacitors.

A novel mesoporous CoMn2O4@rGO composite as an electrode material for hybrid supercapacitor for energy storage device applications

Cobalt‑manganese spinel oxide (CoMn2O4) was hybridized with reduced graphene oxide (rGO) via a facile hydrothermal process and a highly porous three-dimensional (3D) structure was constructed. The phase structure, chemical bands, morphology and chemical state of the synthesized powders were investigated by X-ray diffraction (XRD), Raman spectroscopy, field emission secondary electron microscopy (FE-SEM) and X-ray photoelectron spectroscopy (XPS). CoMn2O4@rGO electrode delivered high specific capacitance of 1578 Cg−1at 1 Ag−1 in 1.0 M KOH electrolyte and an outstanding cycling stability with 94.2 % retention over 5000 cycles, suggesting the great potential application of this material in advanced energy storage device. The rGO makes great contributions to hybrid through supplying a conductive support for CoMn2O4, resulting in the prominent specific capacitances and outstanding cycle stability. Besides, the assembled CoMn2O4@rGO//AC asymmetric supercapacitor (ASC) displays the maximum energy density of 35.6 Whkg−1 at a power density of 8916.9 Wkg−1. Significantly, an ultralong cycling life of 98.2 % capacitance retention is achieved for the ASC device after 10,000 charge/discharge cycles at 1 Ag−1.

Kinetic study of hybrid supercapacitor using transition metal quantum dots @ graphenes composite as a model electrode

In this study, a series of materials with electric double-layer capacitance (EDLC) and pseudocapacitance (PC) have been prepared by adjusting the functional groups and anchoring transition metal quantum dots (TMQDs) on the surface of reduced graphene oxide (rGO) by chemical bonds. The nano-sized TMQDs interlayered in rGOs can contribute a large portion of PC, meanwhile rGOs supply the EDLC to the hybrid supercapacitor. Electrochemical testing results demonstrated that the Fe/Co/Ni TMQDs anchored the rGO (Fe/Co/Ni-TMQD@rGO) exhibited the improved capacitive and rate performances. To elucidate the reaction kinetics of the electrodes, the capacitance contributions of diffusion-controlled processes (DCPs) and surface-controlled processes (SCPs) were separated by the theoretical calculation. It was found that the capacitance contributed by the DCPs is closely related with the number of the valence electrons of the iron group transition metal elements (ITMEs). The ITMEs with more valence electrons exhibited the higher DCPs contribution to the capacitance of the composite. Further, the quantum chemical calculation results suggested that OH– adsorption energy is deeply related to the contribution proportion of SCP to the total capacitance. The discovered mechanism supplies a guidance to the design and development of novel composite electrode materials for hybrid supercapacitors.

Decoration of sea-urchin-like NiCoP coated with WSe2@ZnS as an advanced electrode material for hybrid supercapacitors

The manufacture of creative, efficient, and effective electrodes for use in energy storage systems is an ideal solution to the energy crisis. As a superior electrode for use in energy storage applications, we have synthesized Nickel cobalt phosphate (NiCoP) that has been covered with WSe2@ZnS using the hydrothermal approach described in our current work. The targeted hybrid supercapacitor electrode consists of NiCoP/WSe2@ZnS and has a high specific capacity of approximately 2,416 Fg−1 at 1 Ag−1. Moreover, it has shown excellent cycling stability, retaining 96% of its capacity after 5000 cycles. NiCoP/WSe2@ZnS is employed as the positive electrode and activated carbon (AC) is used as the negative electrode in the asymmetric supercapacitor. This permits the device to have a capacitance of 178 Fg−1 at a current density of 0.5 mAg−1. The manufactured asymmetric supercapacitor has a power density of 1064 Wkg−1 and a maximum energy storage capacity of 46.4 Whkg−1. Because of its outstanding electrochemical properties, metal phosphate will soon be recognized as a novel and attractive active material with potentially useful in energy storage applications.

Self-assembled dandelion-like NiS nanowires on biomass-based carbon aerogels as electrode material for hybrid supercapacitors

Self-assembled dandelion-like NiS nanowires on biomass-based carbon aerogels as electrode material for hybrid supercapacitors

Defect-Engineered Fe3C@NiCo2S4 Nanospike Derived from Metal-Organic Frameworks as an Advanced Electrode Material for Hybrid Supercapacitors.

The rational synthesis and tailoring of metal-organic frameworks (MOFs) with multifunctional micro/nanoarchitectures have emerged as a subject of significant academic interest owing to their promising potential for utilization in advanced energy storage devices. Herein, we explored a category of three-dimensional (3D) NiCo2S4 nanospikes that have been integrated into a 1D Fe3C microarchitecture using a chemical surface transformation process. The resulting electrode materials, i.e., Fe3C@NiCo2S4 nanospikes, exhibit immense potential for utilization in high-performance hybrid supercapacitors. The nanospikes exhibit an elevated specific capacity (1894.2 F g-1 at 1 A g-1), enhanced rate capability (59%), and exceptional cycling stability (92.5% with 98.7% Coulombic efficiency) via a charge storage mechanism reminiscent of a battery. The augmented charge storage characteristics are attributed to the collaborative features of the active constituents, amplified availability of active sites inherent in the nanospikes, and the proficient redox chemical reactions of multi-metallic guest species. When using nitrogen-doped carbon nanofibers as the anode to fabricate hybrid supercapacitors, the device exhibits high energy and power densities of 62.98 Wh kg-1 and 6834 W kg-1, respectively, and shows excellent long-term cycling stability (95.4% after 5000 cycles), which affirms the significant potential of the proposed design for applications in hybrid supercapacitors. The DFT study showed the strong coupling of the oxygen from the electrolyte OH- with the metal atom of the nanostructures, resulting in high adsorption properties that facilitate the redox reaction kinetics.

Highly porous nanocomposites of Mn doped cobalt-based hydroxide/sulfide as high-performance electrode materials for hybrid supercapacitors

Cobalt-based nanomaterials are a highly promising class of energy storage materials with high theoretical capacity and excellent long-term service life, such as metal doping and structural porousness of these cobalt-based nanocomposites, have been regarded as effective methods to further increase their active sites and improve their conductivity and performance. However, synthesizing cathode materials with high specific capacity and energy density through simplistic methods remains an immense obstacle. In this study, Mn doped cobalt-based hydroxide/sulfide nanocomposites with large pore volume as well as specific surface area were successfully synthesized. The Co(OH)2/CoS electrode doped with Mn has better charge storage capacity (capacity increase from 586.5C g−1 to 1030.8C g−1 at 0.5 A g−1), excellent rate performance (with a capacity retention of 75.8 % at 10 A g−1). Additionally, a hybrid supercapacitor (HSC) was constructed utilizing Mn-Co(OH)2/CoS and activated carbon (AC). HSC exhibited excellent charge storage capacity (166.3 F g−1 at 0.5 A g−1) and remained at 164.1 % of its original value after 30,000 cycles of testing with high current density. In addition, at a power density of 410.0 W kg−1, the assembled HSC device demonstrates a significant energy density of 62.1 Wh kg−1, revealing that porous Mn-Co(OH)2/CoS electrode materials showed excellent energy storage properties.

Diffusion kinetics of CuCo2O4 nanorods for next‐generation solid state sodium‐ion hybrid supercapacitor

AbstractIn the current study, we report a straightforward and affordable sol‐gel preparation approach for the fabrication of spinel CuCo2O4 nanorods for sodium ion‐based hybrid supercapacitor. The morphological and structural analysis shows that appropriate purity nanorods of CuCo2O4 are formed with good stoichiometry. The electrochemical study of CuCo2O4 nanorods reveals that the electrode has highest specific capacitance of 367 F g−1 at 1 A g−1 in 1 M Na2SO4 electrolyte. Evaluation of the diffusion kinetics of sodium ions through detailed electrochemical evaluations of cyclic voltammogram (CV) showing the charge storage kinetics of CuCo2O4 is primarily performed through the diffusive limited mechanisms, suggesting the battery‐like behavior of CuCo2O4 electrode. Hybrid supercapacitor (HSC) device is fabricated by utilizing CuCo2O4 for positive and reduced graphene oxide (rGO) for negative electrodes material. The polymer gel electrolyte is used in the form of hydrogel membrane made of PVA and Na2SO4, and the HSC device (rGO || CuCo2O4) exhibits energy density of 9.18 Wh kg−1. Therefore, sodium‐ion hybrid supercapacitor electrode materials for this investigation are established using a comprehensive electrochemical kinetics.

NiCo-MOF derived nanostructured NiCo-LDH@Ni(OH)2 heterogeneous composite as electrode material for hybrid supercapacitors

Regulating the composition and microstructure of multiphase nanocomposites can be used to significantly improve the charge storage capacity of the materials. Herein, the thermometal NiCo-MOF was used as precursor, which was placed in the designed alkaline oxidation environment for alkalization treatment, and NiCo-LDH and Ni(OH)2 heterogeneous composite (NiCo-LDH@Ni(OH)2) was prepared. The ratio of Ni/Co in MOF precursor was further regulated to optimize the composition and structure. Finally, NiCo-LDH and Ni(OH)2 with two-dimensional nanosheet structure were obtained when the Ni/Co ratio was 2:1. Benefiting from the nanostructure of electroactive material and the synergistic effect of multicomponent heterogeneous composite, the electrochemical reactivity is effectively improved, which the NiCo-LDH@Ni(OH)2 electrode has a specific capacity of 754.8C g−1 at 1 A g−1. Further, hybrid supercapacitor (HSC) is assembled to explore practical applications device, which the NiCo-LDH@Ni(OH)2//AC HSC device can output energy density of 30.6 Wh kg−1, power density of 799.9 W kg−1, and maintain 89.0 % of the initial performance after 5000 cycles.

A structured CoWO4 synthesized by microwave-assisted hydrothermal process as electrode for hybrid supercapacitor

A structured carambola-like CoWO4 was fast prepared by a microwave-assisted hydrothermal method with the help of urea and NH4F. Physical characterization indicated that the as-obtained CoWO4 displayed a large specific surface area, high dispersion and self-selected orientation of crystal growth. Further electrochemical tests presented a high specific capacity of 492.0 C[Formula: see text]⋅[Formula: see text]g[Formula: see text] at 1 A[Formula: see text]⋅[Formula: see text]g[Formula: see text], low internal resistance and excellent cycle stability as 137.3% capacity maintenance after 8000 cycles at 20 A[Formula: see text]⋅[Formula: see text]g[Formula: see text]. These excellent electrochemical properties for the as-obtained material indicate that CoWO4 has great potential as hybrid supercapacitor electrode materials. This work also provides a new and effective solution for regulating the morphology of CoWO4-based hybrid supercapacitor materials to further improve the electrochemical performance.

Enhanced energy storage performance of the three-dimensional nickel nitride mesh with mesoporous structure derived from nickel hydroxide nanowires for advanced hybrid supercapacitors

Nickel nitrides are considered to be promising for hybrid supercapacitors (HSCs) as electrochemical energy storage materials, owing to their good electrical conductivity. However, nickel nitride is prone to agglomeration in high-temperature preparation process, resulting in lower specific surface area and higher porosity, further inhibiting its energy storage performance in HSCs. Consequently, a three-dimensional Ni3N mesh with a mesoporous structure (3D Ni3N Mesh) was constructed as the electrode material for HSCs via a facile hydrothermal reaction and nitrogenization treatment in this work. The as-prepared 3D Ni3N Mesh was built from Ni3N nanoparticles as the bricks that employed the nickel hydroxide nanowires as the precursors. The electrochemical tests demonstrated that the specific capacity of the as-prepared 3D Ni3N mesh could reach 254.2 mAh g−1 at 1 A g−1 in the three-electrode cell. The specific capacity of the 3D Ni3N mesh is still up to 108.3 mAh g−1, even at a high current density of 30 A g−1. The changes of the micro-nano structure, chemical composition and energy storage mechanism of the 3D Ni3N mesh electrode materials in the charge-discharge process were also analyzed and discussed. To further demonstrate its potential applications, a HSCs was also assembled with the 3D Ni3N mesh and the activated carbon (AC) as the positive and negative electrode respectively. It is worth mentioning that the specific capacity of the 3D Ni3N mesh//AC HSCs is 59.3 mAh g−1 at 0.5 A g−1, while the energy density also reaches 56.2 Wh kg−1 at a power density of 468 W kg−1. In addition, the 3D Ni3N Mesh//AC HSCs still maintains 77.4 % capacity along with an average coulombic efficiency of 98.7 % after 5000 continuous cycles, demonstrating good cyclic reversibility.

Synthesis of NiFe-MOF@NiFeTe nanoparticle-rod heterostructure on nickel foam for high-performance hybrid supercapacitors

In this work, we prepared a novel electrode material NiFe-MOF@NiFeTe nanoparticle-rod heterostructures with high capacity and structural stability on nickel foam using a simple two-step hydrothermal method. The prepared NiFe-MOF@NiFeTe heterostructure combines the advantages of MOF and metal telluride with a large specific surface area, high electrical conductivity, and fast redox reaction. Meanwhile, NiFe-MOF@NiFeTe is uniformly distributed on the nickel foam substrate, which avoids agglomeration and facilitates electrolyte transport. The prepared electrode materials have excellent electrochemical properties. At 5 A/g, the specific capacitance of NiFe-MOF@NiFeTe can reach 1245.2 F/g, and the capacitance retention rate can reach 92.3 % after 1000 cycles. Furthermore, the assembled NiFe-MOF@NiFeTe//AC hybrid supercapacitor has an operating voltage of 1.7 V, an energy density of 267.1 Wh kg−1 at a power density of 1699.9 W kg−1, and a capacitance retention rate of 82.9 % after 5000 cycles at a high current density of 10 A/g. This study provides a feasible strategy for the development of efficient and stable hybrid supercapacitor electrode materials.

Construction of ultrathin NiCo(HPO4)2·3H2O nanosheet with desirable inner boundary for hybrid supercapacitor

The considerably theoretical electrochemical performance makes NiCo(HPO4)2·3H2O a potential electrode material for hybrid supercapacitor (HSC). Nevertheless, its practical application is impeded by the limited preparation process and undesirable structure, causing its incomplete utilization and unsatisfactory electrochemical performance. Herein, we rationally design a freestanding HSC electrode based on NiCo(HPO4)2·3H2O with the inner boundary to achieve its high utilization. The construction of an inner boundary can increase the ion transport channels and active sites during electrochemical processes. The freestanding NiCo(HPO4)2·3H2O-based electrode in three-electrode system delivers high specific capacitance (3005.1 mF cm−2 at 1 mV s−1) and favorable rate capability (2795 mF cm−2 at 10 mV s−1). When evaluated as a cathode and matched with the activated carbon anode, the asymmetrical HSC exhibits a specific capacitance of 2547.3 mF cm−2 (10 mV s−1) and desirable cycling stability after 4000 cycles (87 % capacitance retention).

Self -templated construction of hollow trimetallic MnNiCoP yolk-shell spheres assembled with nanosheets as a satisfactory positive electrode material for hybrid supercapacitors.

Transition metal phosphides (TMPs) demonstrate excellent potential for supercapacitor electrode materials owing to their good theoretical capacity and great electrical conductivity. The electrochemical features of the electrode materials based on monometallic or bimetallic phosphides are not desirable or satisfactory due to their low rate performance, unfavorable energy density, and short durability. One practical solution to overcome the above problems is to bring in heteroatoms to the structure of the bimetallic materials to create trimetallic phosphides. In this work, brand-new MnNiCoP yolk-shell spheres assembled with nanosheets are synthesized in a facile self-templated way using greatly uniform co-glycerate spheres as sacrificial templates, followed by a phosphorization process. Because of the existence of plenty of oxidation-reduction active sites, great surface area (SA) with mesoporous pathways, high electrical conductivity, and synergistic effect of Mn, Ni, and Co atoms, the fabricated MnNiCoP@NiF electrode demonstrates a considerably increased electrochemical efficiency compared with the bimetallic phosphide MnCoP@NiF electrode. Noticeably, the MnNiCoP@NiF electrode exhibits a great specific capacity of 291.24 mA h g-1 at an applied current density of 1 Ag-1, 80% capacity retention at an applied current density of 20 Ag-1, and 91.3% capacity retention after 14 000 cycles. In addition, a hybrid supercapacitor device with a brand-new positive electrode (MnNiCoP@NiF) and an appropriate negative electrode (AC@NiF) demonstrates an energy density of 57.03 W h kg-1 with a power density of 799.98 W kg-1, plus superb cyclability with 88.41% of the primary capacitance after 14 000 cycles.

MoS2 mediated tuning of CuCo2S4–MoS2 nanocomposites for high-performance symmetric hybrid supercapacitors

CuCo2S4–MoS2 nanocomposites were synthesized by optimizing the concentration of MoS2 to enhance electrochemical performance, including storage capacity, energy density, and stability for use as efficient electrode materials in hybrid supercapacitors.

Fabrication of anhydride core-based conductive layered Ni-MOF nanoflakes for high performance supercapacitors

This schematic representation shows the nanoflakes-layered Ni-MOF, which is synthesized from a specific N-trimellitylimido dicarboxylic acid linker. Electrochemical investigation shows that anhydride MOFs are potential electrode materials for hybrid supercapacitors.

Metal–organic framework-derived hollow Co9S8 nanotube arrays coupled with porous FeCo–P nanosheets as an efficient electrode material for hybrid supercapacitors

Hollow Co9S8 nanotubes@FeCo–P nanosheet arrays are synthesized on nickel foam for hybrid supercapacitors.