Excellent Supercapacitive Performance Research Articles

Synthesis of Flower-like Crystal Nickel–Cobalt Sulfide and Its Supercapacitor Performance

In order to improve the pseudocapacitance performance of metal sulfide electrode materials and obtain supercapacitor energy storage devices with excellent electrochemical reversibility and long-term cycle stability, the synthesis of flower-shaped crystal nickel–cobalt sulfide and its supercapacitor performance were studied. NiCo2S4 flower-shaped crystal nickel–cobalt sulfide was prepared by the hydrothermal method with nickel foam as the raw material, and electrode materials were added to prepare supercapacitor electrodes for testing of the supercapacitor performance. The physical properties of flower-shaped crystal nickel–cobalt sulfide were tested by a scanning electron microscope and transmission electron microscope, and the voltammetric cycle and constant current charge and discharge of supercapacitor electrodes prepared from this sulfide were analyzed through experiments. The experimental results showed that the flower crystal microstructure had a positive effect on the electrochemical properties. The capacitance value was always high at different current densities, and the capacity was as high as 3867.8 A/g at pH 12. After 2000 voltage–charge–discharge cycle tests, the petal-like sulfide capacity still had a retention rate of 90.57, the flower crystal nickel–cobalt sulfide still showed an excellent supercapacitor performance and the specific capacity was still high, which demonstrates that this sulfide has excellent cyclic stability and durability in electrochemical applications.

Laser-induced fabrication of porous graphene for flexible planar microsupercapacitors with wide voltage window

Herein, laser-induced graphene (LIG) derived from polyimide (PI) is demonstrated to construct a flexible planar interdigital microsupercapacitors (MSCs) device with wide voltage window through simple laser-direct-writing method. The mechanism study of LIG derived from PI show that the photon energy of the laser is absorbed by the electrons and converted into heat energy, and the rapid energy accumulation produces extremely high temperatures leading to the graphitization of PI film. At the same time, the internal expansion and gas escape from the interior, the graphitized carbon material grows upward, resulting in the formation of porous graphene. As a demonstration of the supercapacitor application, the as-prepared LIG MSCs device show excellent supercapacitance performance, wide voltage window (0–1.8 V) and good mechanical flexibility. When the laser power is 2.75 W, that is, 50 % of the maximum power, the resulting LIG MSCs device has a high specific capacitance of 20.85 mF cm−2, a maximum energy density of 9.38 μWh cm−2, and good cycle stability with a capacitance retention rate of 101.09 % after 15,000 cycles. This work provides a simple method to prepare graphene-based MSCs and demonstrates great potential of the LIG MSCs in flexible wearable electronic devices.

A battery-type cathode with RuO2 modified Ni11(HPO3)8(OH)6 for asymmetric supercapacitors

Phosphates are a kind of promising electrode materials because they can provide numerous cavities and several reaction sites to be favored for storing anions and cations. However, the widespread application of phosphates are limited by their intrinsically low electronic conductivity. RuO2/hydrated RuO2 exhibits high conductivity and excellent electrochemical properties. Reducing its dosage and increasing its specific surface area are the research concerns. Combining less RuO2 to Nickel phosphate (NiP) is expected to improve the electrochemical performance. RuO2-modified NiP (NiP-RuO2) electrode material is synthesized by a one-step hydrothermal reaction and its structural morphology and capacitive properties are investigated. The results indicate that NiP-RuO2 electrode consists of hydrated RuO2 and Ni11(HPO3)8(OH)6, and exhibits excellent battery-type electrochemical supercapacitor performance with a specific capacity of 878.06 C/g at 1 A/g. According to density functional theory (DFT) analysis, Ru-doped Ni11(HPO3)8(OH)6 has a narrower forbidden band width and higher conductivity than Ni11(HPO3)8(OH)6. Furthermore, the asymmetric supercapacitor (ASC) assembled by NiP-RuO2/NF and activated carbon (AC) electrode achieves a high energy density (43.58 Wh/kg) at a power density of 923.47 W/kg. When two ASC devices are connected in series, ten light-emitting diodes (LEDs) can be illuminated for ten minutes.

A free-standing ZnO@NiCo2O4 nanofilm for supercapacitors and zinc-ion batteries with high-rate performance and high energy density

Transition metal oxides are promising candidates for high-performance electrode materials due to their high conductivity and abundant active sites. Nevertheless, its low energy density and poor rate performance limit its application in energy storage devices. Herein, a free-standing ZnO@NiCo2O4-4 nanofilm was sythesised through simple hydrothermal method. This novel material exhibited excellent electrochemical properties as a result of the synergistic effect of ZnO and NiCo2O4. Specially, the ZnO@NiCo2O4-4 electrode a high specific capacitance of 812.5 F g−1 at 1 A g−1 with remarkable rate performance delivers (615.8 F g−1 even at 10 A g−1). The as-prepared ZnO@NiCo2O4-4//AC supercapacitor exhibits a large energy density of 48.8 W h kg−1 at a power density of 375 W kg−1, and the specific capacitance retention rate of the device maintains 82% after 5000 cycles at 3 A g−1. Furthermore, the assembled ZnO@NiCo2O4-4//Zn zinc ion battery can deliver a high specific capacity of 71 mA h g−1. This work offers important guidance for preparing transition metal oxide nanofilms with excellent performance for supercapacitors and zinc-ion batteries.

MOF-Mediated Construction of NiCoMn-LDH Nanoflakes Assembled Co(OH)F Nanorods for Improved Supercapacitive Performance.

The application of transition metal hydroxides has long been plagued by its poor conductivity and stability as well as severe aggregation tendency. In this paper, a novel hierarchical core-shell architecture, using an F-doped Co(OH)2 nanorod array (Co(OH)F) as the core and Mn/Ni co-doped Co(OH)2 nanosheets (NiCoMn-LDH) as the shell, was constructed via an MOF-mediated in situ generation method. The obtained Co(OH)F@ NiCoMn-LDH composites exhibited excellent supercapacitive performance with large specific capacitance as well as improved rate capability and long-term stability. The effect of the Ni/Mn ratio on the supercapacitive performance and energy storage kinetics was systematically investigated and the related mechanism was revealed.

Waste polyethylene terephthalate plastic derived Zn-MOF for high performance supercapacitor application

A simple chemical approach was used to prepare Zn-MOF or MOF-5 derived from polyethylene terephthalate bottles for supercapacitor applications. The morphology, and structure of PET-derived MOFs were characterized using various techniques, including scanning electron microscopy, transmission electron microscopy, X-ray diffraction, thermogravimetric analysis, fourier transform infrared spectroscopy, and BET surface area and nitrogen adsorption/desorption analysis. The BET surface area of MOF-5 was determined to be 88 m2g−1 and N2 adsorption–desorption analysis, showed the type-IV isotherms and suggest the existence of capillary condensation within the meso- and micropore structures. An excellent specific capacitance ranging from 341 to 191 F g−1 recorded form the scan rate of 2–200 mV s−1 by CV for Zn-MOF. Moreover, the highest specific capacitance 353 F g−1 calculated at 0.5 A/g current density. The highest value of specific capacitance Cs 353 F g−1 was found for lowest current density of 0.5 A/g. An excellent cyclic stability was obtained after running 2000 cyclic runs at a scan rate of 50 mV s−1. The small semicircle of EIS plot exhibits superior electrochemical performance of the Zn-MOF. The waste PET plastic derived Zn-MOF showed an excellent supercapacitor performance which can be utilized in energy storage applications. This approach not only facilitates environmental remediation but also offers a valuable organic linker for energy material synthesis.

One-pot synthesis of phosphorous, iodine atoms co-functionalized graphene for high-performance supercapacitor and flame-retardant applications

There has been extensive research on heteroatom-doped graphene for electrochemical energy storage and flame-retardant (FR) applications. Herein, we used a one-pot method for developing phosphorous, iodine co-doped reduced graphene oxide (PI@rGO) from red phosphorus and iodine via in situ graphene oxide (GO) reduction for supercapacitor and FR applications. In a symmetrical two-electrode cell device, the as-prepared PI@rGO demonstrated good super capacitive performance of 178 F g−1 at a current density of 1.0 A g−1, along with an exceptional energy density of 20 Wh kg−1 and power density of 1791 W kg−1. The as-synthesized PI@rGO demonstrated outstanding cyclic stability at a high current density of 10 A g−1, retaining up to 84 % of its initial capacitance after more than 6000 recurrent charge–discharge cycles. The synthesized PI@rGO showed excellent FR properties toward cotton fabric and sustained cotton fabric up to 337 s with continuous flame exposure. The control cotton fabric was completely burned in 16 s. The synthesized PI@rGO coated cotton fabric showed an excellent value of 39 % limiting oxygen index and residual char length of 2 cm. With the excellent super capacitive performance and FR properties, PI@rGO can be a promising candidate for different applications including supercapacitors and FR products.

Green synthesis of MOF/CNT gels via in-situ physical mixing strategy toward quasi-solid-state Li-ion hybrid capacitor

Compositing metal-organic frameworks (MOFs) with carbon nanotubes (CNTs) can effectively improve their conductivity and structural instability to achieve excellent supercapacitor performance. However, the two main traditional composite strategies of ex-situ physical mixing and in-situ chemical growth still have some limitations, such as the heterogeneous dispersity and the destruction of CNTs, etc. In this work, we propose a green in-situ physical mixing method to construct advanced MIL-100-Fe/CNT architecture. An adding content of 10 % for CNTs results in the optimal composite structure within homogeneous dispersion and favorable interactions between MOF host and CNT guest, achieving a high specific capacitance of 431.6 F g−1 at the current density of 1 A g−1, which is much higher than of the pristine MOF (143.1 F g−1). An in-depth electrochemical study illustrates that the moderate addition of CNTs promotes the fast charge transfer dynamics of Li-ion in the composite electrode while the excessive CNTs will lead to localized aggregation and property degradation. A quasi-solid-state Li-ion hybrid capacitor device was assembled, displaying a high energy density of 20.2 W h kg−1 and a long cycle life of 89.4 % capacitance retention after 8000 cycles. The contribution has provided a new direction for constructing advanced MOF-based composite architectures for energy storage applications.

Built-in electric field and selenium vacancies synergistically enhance NiSe2@Co0.85Se high-performance supercapacitors

Sluggish kinetics and poor cycling stability are two major obstacles limiting large-scale energy storage in battery-type supercapacitors. Herein, a novel strategy has been proposed to address these issues, which is to use a simple two-step electrodeposition technology to prepare the NiSe2@Co0.85Se/NF(denoted as NS@CS/NF) core-shell heterostructure, generate built-in electric field, and subsequently introduced anionic vacancies to successfully construct unique Se vacancies-rich composites (denoted as Sev-NS@CS/NF). Systematic characterisation analysis and density functional theory (DFT) calculations confirm that Se vacancies and heterogeneous interfaces can modulate electronic structure and promote fast reaction kinetics to achieve excellent supercapacitor performance, with a specific capacitance of 1530 C g−1 at 1 A g−1, and a capacity retention of 86.35% even after undergoing 10,000 charge-discharge cycles. Furthermore, a hybrid supercapacitor (HSC) was constructed using Sev-NS@CS/NF as the cathode and activated carbon (AC) as the anode, exhibiting an energy density of 80 Wh kg−1 at 812 W kg−1 and maintained impressive performance metrics. Notably, when two HSC units were connected in series, they successfully illuminated an LED diode for a duration of 15 min, showcasing the considerable potential of this HSC device for various energy storage applications.

Carbon quantum dots modified and Y3+ doped Ni3 (NO3 )2 (OH)4 nanospheres with excellent battery-like supercapacitor performance.

Supercapacitor is an important energy storage device widely used in the automobile industry, military production, and communication equipment because of its fast charge-discharge rate, and high power density. Herein, carbon quantum dots modified and Y3+ doped Ni3 (NO3 )2 (OH)4 (NiY@CQDs) nanospheres are prepared by a solvothermal method and used as an electrode material. The electrochemical properties of NiY@CQDs were measured in a three-electrode system. An asymmetric supercapacitor (ASC) cell was assembled with activated carbon (AC) as the anode and NiY@CQDs as the cathode. The electrochemical properties of the ASC device were measured in a two-electrode system. Experimental results show the shape of NiY@CQDs is petal-shaped and the introducing carbon quantum dots and doping Y3+ significantly increases the specific surface area, conductivity, and specific capacitance of Ni3 (NO3 )2 (OH)4 . The mass-specific capacitance of NiY@CQDs reaches up to 2944 F g-1 at a current density of 1 A g-1 . The asymmetric supercapacitor of NiY@CQDs//AC has a high energy density of 138.65 Wh kg-1 at a power density of 1500 W kg-1 , displaying a wide range of application prospects in the energy storage area.

The hydrothermal synthesis of d-Ti3CN/V2O5 hollow spheres for enhanced supercapacitors applications

In this work, d-Ti3CN MXene was obtained by selective etching of Al from Ti3AlCN by hydrofluoric acid, and a hydrothermal method was employed to prepare d-Ti3CN/V2O5 hollow spheres. The prepared d-Ti3CN/V2O5 hollow spheres showed enhanced electrochemical properties. V2O5 hollow spheres expanded the distance between d-Ti3CN MXene sheets, leading to fast electron transport and improved electrochemical performance of d-Ti3CN/V2O5 hollow spheres. A specific capacitance of 340 F g−1 was achieved at 1 A g−1 current density, which is higher than that of d-Ti3CN MXene (321 F g−1) and V2O5 hollow sphere (155 F g−1). The initial capacitance retention is 89 % after 6000 cycles of constant current charge and discharge at the current density of 10 A g−1. In short, d-Ti3CN/V2O5 hollow spheres show excellent supercapacitor performance regarding specific capacitance and stability.

Interatomic interaction of 2D crumpled V2O5 nanosheets layered with Ni-MOF as a bifunctional electrocatalyst for overall water splitting and supercapacitor applications

Herein, we have synthesized a highly efficient and economical noble metal-free catalyst via a novel combination of V2O5 nanosheets and Ni MOF. The critical points of this study are (i) achieving a 2D layer structured crumpled V2O5 nanosheets without excessive stacking/aggregation using freeze drying method, (ii) decorating Ni-MOF over the crumpled V2O5 nanosheets to attain an excellent homogeneity and (iii) developing a V2O5 based novel and bifunctional electrocatalyst for overall water splitting and supercapacitor applications. Forming a well-interlinked morphological structure accompanies a homogeneous dispersion of Ni MOF over the V2O5 nanosheet. Among the multiple compositions, the NiV4 exhibited superior electrocatalytic oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) performances with an overpotential (η30) of 336 mV and 108 mV, respectively. NiV4 also displayed remarkable stability as confirmed by chronopotentiometry (24 h) and CV (after 5000 cycles). The excellent OER performance is possible due to the interatomic interaction and the heterojunction formation between V2O5 nanosheets and Ni MOF, resulting in the preferential adsorption of ⁎OOH reaction intermediates to Ni active sites. During HER, the interfacial interaction between V2O5 nanosheets and Ni MOF allowed the OH− to adsorb on the V5+ center. Furthermore, the Ni active sites simultaneously accelerated the Volmer step by promoting the H adsorption. The uniform mass transfer routes aid in fast charge transfer, resulting in excellent OER and HER performances. Interestingly, in the 2-electrode system, the NiV4 exhibited an overpotential of 1.81 V at 10 mA cm−2 and excellent durability over 15 h. For supercapacitor applications, the NiV4 exhibits efficient specific capacitance (546 Fg−1 at 1Ag−1). Furthermore, the NiV4 electrode provides significant long-term stability during the supercapacitor application, with the stability being consistent after 10,000 cycles. The NiV4 offers excellent water splitting and supercapacitor performance due to its multifunctional properties and remarkable structural integrity.

Advanced asymmetric supercapacitors based on two-step activated carbon cloth with long cycle life

A simple and efficient method is developed to activate commercial carbon cloth by creating a large number of hierarchical pores on the surface of carbon cloth and introducing numerous pseudocapacitance oxygen-containing functional groups to achieve excellent electrochemical performance for supercapacitors. The obtained active carbon cloth (AECC) shows core-shell structural with high surface area and abundant functional groups. Benefiting from these fascinating properties, the AECC displays an areal specific capacitance of 1.06 F cm−2 at 1 mA cm−2 and the rate capability of 40.8 % (from 1 to 32 A cm−2). More impressively, after 10,000 time charge/discharge cycles, AECC still maintains 100 % of the initial capacitance, indicating its superior cycle stability. The asymmetric supercapacitor with AECC as anode and MnO2/CC as cathode delivers a high energy density of 139.7 mWh cm−2 at 1 W cm−2 and excellent cyclic stability (100 % after 10,000 cycles at 16 mA cm−2). This work may provide a reference for exploring and designing high-performance carbon electrodes.

Correction: Synthesis of TiC nanotube arrays and their excellent supercapacitor performance

Correction for ‘Synthesis of TiC nanotube arrays and their excellent supercapacitor performance’ by Tongxiang Ma et al., J. Mater. Chem. A, 2022, 10, 9932–9940, https://doi.org/10.1039/D2TA00957A.

Supercapacitance Performance of Mesoporous Mono- and Bi-Metallic Cobalt and Nickel Hydroxides Nanoflakes Chemically Deposited from Foam-Surfactant Liquid Crystal Dual Templates

Mesoporous 2D nanoflakes architectures of mono- and bi-metallic cobalt and nickel hydroxide (meso-Co-Ni(OH)2) hybrids were synthesized using novel chemical precipitation of foam-surfactant liquid crystal dual template (FSDT). The dissolved cobalt and nickel ions within the aqueous region of the Brij®78 surfactant template was reduced by the excess of sodium borohydride reducing agent that simultaneously generates excessive hydrogen foam as a double template. The physicochemical characterizations of the mono- and bi-metallic nanostructured Co-Ni(OH)2 hybrids performed using X-ray diffraction, surface area analyzer, scanning and transmission electrons microscopic techniques showed the formation of highly mesoporous hydroxides 2D nanoflakes architectures having an amorphous structure and surface area up to 253.50 m2/g. The electrochemical and supercapacitance evaluation of the mono-, and bi-metallic mesoporous hydroxides showed excellent Faradaic supercapacitance performance within a wider potential window and a higher charge and discharge rate. In particular the mesoporous monometallic of Co(OH)2, Ni(OH)2, bimetallic Co-Ni(OH)2 with Co/Ni ratios of (1:1), and (1:3), hydroxides showed total capacitances of 204, 869, 943, and 1384, F/g at charging current density of 5.0 A g−1 respectively and capacity retention rate of approximately 99.4% after 300 cycles. This suggests that these materials hold promise as electrode materials for energy storage applications.

Cost effective Cr-doped Co(OH)2 nano-flower assemblies exhibiting excellent electrochemical performance for supercapacitors

Chromium doping along with topology, the nano-flowers exhibit exceptional electrochemical performance. By systematically characterizing the prepared samples of pristine Co(OH)2 and Cr doped Co(OH)2 using a comprehensive series of analytical techniques, including XRD, SEM, TEM, EDX, FTIR, and PL, a profound understanding of their structural and morphological features is achieved. Paving the path for significant advancements in renewable energy storage technology exploration for prime and cost-effective electrode materials for supercapacitors is a major challenge. This paper presents an innovative study on Cr doped Co(OH)2 based nano-flowers. The synergistic role of the average size of fibrous structures comprising nano-flowers is in the range of 20 nm showing high surface area of the prepared sample. Electrochemical performance was acquired in 2 M KOH electrolyte by CV, GCD and EIS. To understand the rate of ion transport within the sample, diffusion coefficient has been calculated. The discernible improvement in redox behavior, maximize the capacitance of 3 % Cr-Co(OH)2 to 1252 Fg−1 and diffusion coefficient to 1.509 × 10−5 cm2s−1. Furthermore, the power law unveils the pseudocapacitive nature of 3 % Cr-Co(OH)2 electrode material and unprecedented cyclic stability by possessing retention rate of 93 % even after 5000 cycles. All these calculated properties exhibit the immense potential of doped nano-flowers as a reliable source of high-energy electrode material.

Facile synthesis of nanostructured sodium and MoS2 incorporated Ni-MOFs with excellent cyclic durability for symmetric supercapacitor application

Highly porous and nanostructured metal-organic frameworks (MOFs) have fascinated enormous interest as electrode active materials for electrochemical energy storage systems, whereas their practical applications are significantly hindered by their relative inferior energy density and cyclability. In this study, MoS2 with layered structure was successfully incorporated onto hierarchical Ni-MOFs via a facile hydrothermal approach. Moreover, sodium cations were introduced to improve electronic conductivity. The resulting nanocomposites (sodium ions and MoS2 incorporated Ni-MOFs) exhibited hierarchical porous structures with varying dimensions, offering increased volume for charge storage and diffusion channels for electrolyte ions. Benefiting from the unique topological architectures, the as-synthesized porous nanocomposites delivered an excellent supercapacitive performance, achieving a superlative energy of 33.33 Wh kg−1 and a power density of 3390 W kg−1. Furthermore, the as-fabricated symmetric supercapacitor device delivered a remarkable cycling durability where the acquired outstanding capacitance retention was 97.42% and coulombic efficiency was 97.82% respectively over more than 10,000 cycles in an aqueous electrolyte.

Synthesis and electrochemical properties of nanocubes Mn2SnS3 for high-performance supercapacitors

Exploring environment-friendly active material-electrolyte combinations has become increasingly necessary with the rising use of supercapacitors. In this study, the potential of ternary Mn2SnS3 on Ni foam as an electrode material was considered. The study investigated the impact of precursors on the morphology of the prepared electrodes utilizing techniques such as X-ray diffraction, energy dispersive X-ray analysis, field-emission scanning electron microscopy, and transmission electron microscopy. Nanocubes Mn2SnS3 (NC-MTS) and nanoworms Mn2SnS3 (NW-MTS) were synthesized via a facile solvothermal route. The results suggest that NC-MTS exhibits better capacitive performance compared with NW-MTS, which means that morphology has a significant effect on the electrochemical reaction. NC-MTS presents excellent supercapacitor performances with a high specific capacity of about 2115 F g−1 at current density 2 A g−1, excellent rate capability of 78% at 17 A g−1 and excellent cycling stability 92% capacitance retention after 3000 GCD cycles. Whereas, NW-MTS illustrated a specific capacity of about 853 F g−1 at current density 2 A g−1, rate capability of 50% at 17 A g−1 and cycling stability of 81% capacitance retention after 3000 GCD cycles. Additionally, an asymmetric supercapacitor NC-MTS/NF//AC based on the NC-MTS/NF as a positive electrode and activated carbon (AC) as a negative electrode was successfully constructed with the excellent electrochemical performance, which demonstrated a high energy density of 60.56 Wh kg−1 and a high power density of 699.89 W kg−1.

Silicon-Carbon nanofiber composite film for supercapacitor applications

A free-standing silicon-carbon nanofiber composite film was synthesized, and the film was investigated for supercapacitor applications. High specific capacitance of 206F/g in the three-electrode system and 242F/g in the two-electrode system at the current density of 1 A/g with energy density of 21.6 Wh kg−1 and the corresponding power density of 401 W kg−1 are obtained. Specific capacitance retention of 94.6 % and Coulombic efficiency of 87.8 % are also demonstrated after 5,000 cycles. The combination of carbon nanofiber as a support and silicon as an active material finally provide excellent supercapacitor performance.

Biofilm-engineered fabrication of Ag nanoparticles with modified ZIF-8-derived ZnO for a high-performance supercapacitor

The particle size, pore structure, and surface area of nanomaterials are critical characteristics that govern their effectiveness in energy storage applications. In addition, as the accessibility of the surface to ions or reactants has a significant impact on the performance of the supercapacitor, thus the properties of designed nanostructures are essential and need to be considered. In this study, a ZnO-based nanomaterial with a high surface area and electronic conductivity was synthesized by combining the thermal treatment of a zeolitic imidazolate framework-8 (ZIF-8) with a biofilm-assisted surface modification method. A nanocomposite of ZnO and carbon (ZnO/C) was prepared by the systematic N2/O2 thermal treatment of ZIF-8. The ZnO/C composite underwent additional modification through the direct synthesis of Ag nanoparticles (Ag@ZnO/C) on the ZnO/C surface.An electrochemically active biofilm (EAB) was used as the reducing tool to synthesize the Ag nanoparticles. The final product, Ag@ZnO/C, was used as the electrode in a supercapacitor. Ag@ZnO/C exhibited a specific capacitance of 368.4C g−1 (921 F g−1) at a current density of 1 A g−1, which was remarkably higher than that of ZnO/C (383.5 F g−1). The cyclability of Ag@ZnO/C was also evaluated, demonstrating a 95 % capacity retention over 9000 cycles. The significantly enhanced surface area and electronic conductivity of Ag@ZnO/C resulted in an excellent supercapacitor performance.