High-performance Asymmetric Supercapacitors Research Articles

Nickel-molybdenum bimetallic sulfide decorated biomass derived carbon support for high performance asymmetric supercapacitor application

Biomass - derived carbon electrode material with a porous structure is widely used in supercapacitor applications, which can improve electron transfer and shorter ion diffusion pathways. In this work, the garlic peel biomass carbon (GPBC), NiMo3S4(NMS) and garlic peel biomass carbon decorated with NiMo3S4 (GPBC/NMS) composite were prepared through a in situ two-step hydrothermal method. The synthesized materials were characterized by X-ray diffraction (XRD) and field emission scanning electron microscopy (FE-SEM), energy dispersive x-ray spectroscopy (EDS), Transmission electron microscopy techniques (TEM), Raman spectroscopy and Brunauer-Emmett-Teller (BET) techniques were used to analyze the structure, morphology and specific surface areas and X-ray photoelectron spectroscopy (XPS). The prepared bimetallic metal sulfide on a biomass - derived carbon namely the GPBC/NMS composite is used in supercapacitor application. The GPBC/NMS composite electrode exhibits good cycle performance with high specific capacity of 304C/g at current density of 1 A/g in a 3 M KOH electrolyte solution. The electrochemical performance of the GPBC/NMS//GPBC asymmetric supercapacitor device produces an excellent energy density 45.5 Wh kg−1 at a power density of 1125 W kg−1 in the 1.6 V operating potential window. The GPBC/NMS//GPBC also exhibits 93 % retention of its initial capacitance after the 10,000 GCD cycle performance. The above results demonstrate a new way of developing high performance electrode materials for energy storage applications.

Nickel-copper-cobalt mixed oxide electrode material for high performance asymmetric supercapacitor

Nickel copper cobalt oxide (NiCuCoO) ternary metal oxide nanoparticles were synthesized by employing the hydrothermal method. NiCuCoO electrode demonstrates a specified capacity of 596 C g−1 at 1 A g−1, high capacitance retaining of 99% even if 1000 sequences at the density of current 10 A g−1, and significant extended cyclic strength over 1000 sequences. The gathered asymmetric supercapacitor (ASC) tool via NiCuCoO as the cathode and activated carbon as anode materials achieve a specified capacity of 168 C g−1 at a current density of 1 Ag−1, an excellent capacity retaining of 95% even later than 5000 sequences at a density of current 10 A g−1. The fabricated device exhibits a high density of energy and power is 96 Wh kg−1 and 841 W kg−1. The prepared material confirms an excellent capacitance routine, so this work represents for a next-generation energy storage device.

Preparation of Positive and Negative Composite Electrode Materials for High-Performance Aqueous Asymmetric Supercapacitor by a Sequential Two-Step Reaction

Preparation of Positive and Negative Composite Electrode Materials for High-Performance Aqueous Asymmetric Supercapacitor by a Sequential Two-Step Reaction

3D Architecting triple gradient graphene-based fiber electrode for high-performance asymmetric supercapacitors

High-performance fibrous architectures and controllable fabrication methods for active nanomaterials are fundamental in the development of fiber-based supercapacitors (FSCs). Herein, we rationally designed a triple gradient structured fibrous electrode based on three-dimensional (3D) architectural approach with Ni3S2 nanoflakes (Ni3S2 NFs) in situ growth on Ni-coated graphene fiber (Ni3S2-NiGFs) for highly energy-dense asymmetric supercapacitors. Remarkably, the Ni-metal coating imparted the Ni3S2-NiGFs exceptional electrical conductivity (619.8 S cm−1), mechanical strength (335.0 MPa), and flexibility without significantly compromising its density. Moreover, the unique 3D interconnected ultrathin Ni3S2 NFs significantly increase the contact area between the electrode and the electrolyte solution, providing abundant redox activity to facilitate ion transport and accumulation. Therefore, the fibrous electrode showcased a remarkable areal specific capacitance of 1387.6 mF cm−2 at 3 mA cm−2 in 3 M KOHaq electrolyte, while its asymmetric FSCs delivered an impressive areal energy density of 15.6 μW h cm−2 at power density of 1.0 mW cm−2 along with durable cycle life (86.7 % of the initial specific capacitance retention over 10,000 cycles). In summary, the featured work provides a facile but robust electrode design to realize highly energy-dense flexible energy storage devices for next-generation wearable industries.

Fabrication of NiCo2O4@NiCo2S4 Core@Shell nanostructured arrays decorated over the rGO sheets for High-Performance asymmetric supercapacitor

Reliable and cost-effective energy storage systems can only be designed using electrode materials that exhibit high energy densities and consistency. In this work, NiCo2S4@NiCo2O4 core@shell nanoneedle-like nanostructures (NCS@NCO/rGO) are synthesized over the rGO sheet using a new and easy hydrothermal approach. Electrolyte transport and sulfur incorporation during charge–discharge reactions are both made easier by the core@shell nanostructured arrays' large active surface area. The ternary electrodes made of NCS@NCO/rGO have a rich mesoporous framework, a large surface area of 156.5 m2g−1, and an ideal distribution of pore sizes centered at 8.1 nm. An impressive specific capacitance of 2011 Fg−1 at 10 mV s−1 demonstrates the exceptional performance of the NCS@NCO/rGO ternary electrode. The ternary electrodes made of NCS@NCO and rGO have been shown to have remarkable cyclic stability in reports, maintaining 91 % of their capacity after 10,000 cycles. With an impressive power density of 983 Wkg−1 and an outstanding cycling durability of 98.8 % retention of the original capacitance after 10,000 cycles, the manufactured NCS@NCO/rGO//AC ACS displays a noticeable energy density of 68.5 Whkg−1. The mesoporous structure is excellent for increasing the characteristics of supercapacitor electrodes, as these astounding results can attest.

Lignosulfonate-Assisted Synthesis of Porous Carbon-Supported MnO2 Composites with Reinforced Interface Bonding for High-Performance Asymmetric Supercapacitors

Lignosulfonate-Assisted Synthesis of Porous Carbon-Supported MnO₂ Composites with Reinforced Interface Bonding for High-Performance Asymmetric Supercapacitors

Carbamide-mediated facile sol-gel synthesis of porous flower-like ZnCo2O4 microspheres for high-performance asymmetric coin cell supercapacitors

The design and development of ultrahigh-performance nanomaterials possessing novel characteristics are needed to achieve reliable energy storage performance. To satisfy the needs, diverse electrode materials are explored. Even though carbon-based materials hold high surface area and conductivity, their specific capacitance value fails to deliver high-performance applications. Therefore, pseudocapacitive transition metal oxide is adopted to overcome these issues. Among all Zinc Cobaltite, a binary transition metal oxide is widely explored owing to its fascinating electrochemical properties. As most of the synthesis of these kinds of materials requires the hydro/solvothermal method, herein, we have proposed the concept of a facile sol-gel method to prepare this class of materials by using Carbamide as both structure director and fuel to achieve the porous flower-like Zinc Cobaltite. The prepared material delivers the notable gravimetric specific capacitance of 513.3 F g−1. Owing to its unique morphology and porous structure, ion channelization is feasible, which will enhance the electrochemical reaction. Constructed asymmetric coin cell supercapacitor showed an extraordinary specific capacitance of 106.5 F g−1 and energy density of 56.2 Wh kg−1, demonstrating an impressive ability to retain 89.6 % of its capacitance after 4000 cycles at a current density of 6 A g−1. Due to the remarkable electrochemical behavior, this work can act as a guiding tool for designing efficient and cost-effective energy storage devices that will hold prodigious potential in commercial energy storage applications.

Facial design and synthesis of CoAl-LDH-doped MXene with nanosheet structure for high-performance asymmetric supercapacitors

Facial design and synthesis of CoAl-LDH-doped MXene with nanosheet structure for high-performance asymmetric supercapacitors

High-performance asymmetric supercapacitors assembled with novel disc-like MnCo2O4 microstructures as advanced cathode material

Herein, porous MnCo2O4 with disc-like (MnCo2O4-discs) and ring-like (MnCo2O4-rings) microstructures were respectively synthesized using an initial hydrothermal method at different temperatures and a calcination treatment in air. The electrochemical properties of these MnCo2O4 materials were investigated in three-electrode and two-electrode systems, and as such, MnCo2O4 presented a battery-like electrochemical response. The specific capacity of MnCo2O4-discs was determined to be 296.1C/g at 1 A/g, superior to 246.3C/g for MnCo2O4-rings. An asymmetric supercapacitor (ASC) was assembled with MnCo2O4 as the cathode and activated carbon (AC) as the anode to evaluate the potential for practical application. The MnCo2O4-discs//AC ASC exhibited an energy density (Ed) of 35.8 W h kg−1 at a power density (Pd) of 927.5 W kg−1. For the MnCo2O4-rings//AC ASC, an inferior Ed of 31.4 W h kg−1 under 890.9 W kg−1 was achieved. Furthermore, the two ASCs presented outstanding cyclic performance after 5000 cycles at 6 A/g. The exceptional properties of MnCo2O4 microstructures can be applied to the assembly of ASC devices, which can have promising potential for application in electrochemical energy storage. This synthetic method is straightforward, cost-effective, and can be extended to fabricate similar electrode materials with superior electrochemical performance.

Highly matched porous MXene anodes and graphene cathodes for high-performance aqueous asymmetric supercapacitors

Aqueous asymmetric supercapacitors (ASCs) provide promising prospects for electronic systems in the future that require high energy density, power density and cycling life, due to their advantages such as low cost, safe operation and environmental friendliness. However, developing well-matched anodes and cathodes with complementary potential windows and coordinated charge storage kinetics remains a significant challenge. Here, we constructed porous MXene- and graphene-based films with nitrogenous and phosphorous terminals as anodes and cathodes, respectively, alleviating the restacking of nanosheets, generating more electrochemical active sites and improving the electrolyte penetration. The assembled aqueous ASCs based on the porous MXene and graphene films could achieve an excellent energy density of 26.8 Wh kg−1 at 425 W kg−1, high rate performance, and remarkable cycling stability with 97.3 % retention after 20,000 cycles. This work demonstrates a novel concept to develop high-performance aqueous ASCs by surface engineering of two-dimensional porous electrodes with matched structural and electrochemical properties.

Binder free cobalt Manganese layered double hydroxide anode conjugated with bioderived rGO cathode for sustainable, high-performance asymmetric supercapacitors

Metal-organic frameworks (MOFs) possessmultifunctional characteristicssuch as tuneable pore structure and high specific surface area and are being designed with great interest to enhance the electrochemical properties of current energy storage devices. In this aspect, MOFs-derived layered double hydroxides (LDHs) are important candidates for advanced supercapacitors due to their high electrochemical activity and electric conductivity. Herein, we report synthesis of Cobalt Manganese layered double hydroxides (CoMn LDH) utilising Co MOF as a precursor via ion exchange method, while optimising the dosage of Mn to achieve the best possible structural outcome. The unique structure of CoMn LDH expressed high electrochemical parameters possessing specific capacitance of 1305F/g at 1 A/g. Afterwards, an asymmetric supercapacitor device was fabricated employing CoMn LDH as cathode and coffee grounds derived rGO (reduced graphene oxide) as anode. The as-prepared asymmetric supercapacitor device demonstrated a maximum working potential window of 1.2 V with energy and power density of 23.8 Wh/kg and 0.30 kW/Kg respectively. The device also exhibits superiorcoulombic efficiency and capacitance retention of 71.11 % and 82.7 % respectively over 3010 charge–discharge cycles that represents an effectiveapproach towards sustainable and effectiveenergy storage devices. In a nutshell, our study centred on adjusting composition, engineering structures, and assembling devices.

Fabrication of nickel foam/MXene/CoAl-layered double hydroxide by electrodeposition as electrode material for high-performance asymmetric supercapacitor

Layered double hydroxides (LDH) have become one of the highly promising electrode materials due to large specific area, excellent cycling stability and high energy density. However, the large internal resistance limits their applications in energy storage. The introduction of highly conductive materials is expected to solve this problem. In here, nickel foam (NF)/MXene/CoAl-LDH is prepared by electrodepositing CoAl-LDH on the surface of MXene-coated NF, and the effects of Co:Al ratio on the electrochemical properties are investigated in detail. The best electrochemical performance of the composite is obtained when Co:Al=2:1, with a specific capacitance of 646.7 F g−1 at 0.5 A g−1 and 450.8 F g−1 at 5 A g−1. Furthermore, the asymmetric supercapacitor is assembled with NF/MXene/CoAl-LDH as the positive electrode and activated carbon (AC) as the negative electrode. The voltage window of the device can reach 1.6 V. The specific capacitance of the device is 126.87 F g−1 at a current density of 0.5 A g−1. At the power density of 400 W kg−1, the energy density of 45.11 Wh kg−1 is provided. Even at the high power density of 4000 W kg−1, the energy density can still reach 17.88 Wh kg−1. After 5000 cycles at a current density of 5 A g−1, it still maintains a capacity retention rate of 92.9%. The asymmetric device with its high specific capacitance, long term stability and good power density and energy density has a great potential in energy storage applications.

Synthesis of oxygen vacancy-engineered Fe2O3 nanospheres on three-dimensional reduced graphene oxide for ultra-energy density performance of asymmetric supercapacitors

The synthesis of oxygen vacancy (VO) -engineered Fe2O3 (Fe2O3-x) nanospheres on three-dimensional reduced graphene oxide (3D rGO/Fe2O3-x) is proposed via a gentle and high-efficiency hydrothermal approach under reducing conditions for a high-performance asymmetric supercapacitors. The smooth and rounded 3D rGO/Fe2O3-x hydrogel appears to be intact, which possesses extremely light weight and excellent strength. The micromorphology of 3D rGO/Fe2O3-x presents a 3D interconnected macroporous network structure, and the Fe2O3-x nanospheres are distributed on the surface of 3D rGO. The specific capacity of the 3D rGO/Fe2O3-x is up to 273.2 mAh/g. An asymmetric supercapacitor 3D rGO/Fe2O3-x||3D rGO exhibits an ultrahigh energy density of 114 Wh/kg at a power density of 140 W/kg. Over 20000 cycles, the capacitance retention fading and the coulombic efficiency are 6.18% and ∼100%, respectively. Outstanding supercapacitor performances of the 3D rGO/Fe2O3-x||3D rGO are attributed to the formation of the VOs in Fe2O3 crystal structure and the distribution of Fe2O3-x nanospheres on the 3D rGO. The 3D rGO/Fe2O3-x displays great potential for utilization as high-performance supercapacitors.

Facile synthesis of hybrid electrode by bimetallic MOFs/polyaniline composite for high-performance asymmetric supercapacitors

Facile synthesis of hybrid electrode by bimetallic MOFs/polyaniline composite for high-performance asymmetric supercapacitors

3D Nanoflower-like and core-shell structured heterogeneous CuCo2O4@CuCo2S4@Ni(OH)2 electrode materials for high-performance asymmetric supercapacitor

The planning and synthesis of nanocomposite materials with reasonable core-shell heterostructure are of great significance in enhancing the energy density, structural stability as well as long cycle life of asymmetric supercapacitors. We have successfully prepared CuCo2O4@CuCo2S4@Ni(OH)2 core-shell 3D nanoflower array electrode material, resulting in outstanding performance of the assembled supercapacitor. Firstly, CuCo2O4 (CuC) nanowires are grown directly on nickel foam (NF) through hydrothermal and calcination reactions, followed by the formation of heterogeneous CuCo2O4@CuCo2S4 (CuC@CuS) nanoflowers via a hydrothermal reaction by using Na2S·9H2O as a vulcanizing agent. Finally, CuCo2O4@CuCo2S4@Ni(OH)2 electrode material is obtained via the electrodeposition method under a constant voltage. The prepared electrode material is composed of conductive CuC@CuS nanoflowers as the core and deposited Ni(OH)2 nanosheets as the shell, which effectively promotes ion diffusion, increases the reactive area and thereby enhances the electrochemical performance. Impressively, the composite electrode CuC@CuS@Ni(OH)2/NF material achieves an exciting high capacitance of 3753.6 F g−1 (1 A g−1), and the cycle stability is reduced by only 7.1 % after 10,000 cycle tests in the standard three-electrode system. Furthermore, the asymmetric supercapacitor (ASC) device composed of activated carbon (AC) and CuC@CuS@Ni(OH)2 exhibits 729.75 W kg−1 power density under 59.11 Wh kg−1 energy density. The aforementioned findings demonstrate that the CuC@CuS@Ni(OH)2 nanoflower array is a very potential energy storage material.

Amorphous-crystalline CoMoS4 with high mass loading for high-performance asymmetric supercapacitors

CoMoS4 as electrode material in supercapacitors is attributable to the high theoretical capacitance of CoSx and MoS2. However, there is still room for improvement in its capacitive performance. Besides, electrode material possessing good electrochemical properties is usually restricted to low mass loading. In this work, four amorphous-crystalline CoMoS4 materials were obtained by a precipitation process through altering additive in a mixed solution and subsequent by a thermal treatment process. As-synthesized four CoMoS4 materials consist of numerous amorphous phase accompanying with a very few crystalline phase as well as display different morphology and structure. All CoMoS4 materials with high mass loading achieve high specific capacitance. At 0.5 A g−1, CoMoS4–1, CoMoS4–2, CoMoS4–3, and CoMoS4–4 possess a specific capacitance of 1720.9, 2560.6, 1914.5, and 2498.7 F g−1, respectively. Amongst the four CoMoS4, CoMoS4–2 delivers the highest specific capacitance at 0.5∼4 A g−1. However, the specific capacitance of CoMoS4–3 reaches the largest value at 8∼16 A g−1. CoMoS4–3 and CoMoS4–1 exhibit good rate capability, much better than those of CoMoS4–2 and CoMoS4–4. CoMoS4–3 owns good comprehensive supercapacitive performances related to its optimum amorphous-crystalline ratio, suitable morphology and structure. The assembled CoMoS4–3//AC asymmetric supercapacitor (ASC) using CoMoS4–3 as the positive electrode and activated carbon (AC) as the negative electrode provides a superior energy density (59.2 Wh kg−1 at 425 W kg−1), which is superior to those of previously reported CoMoS4-based ASC devices. In addition, the ASC device displays a satisfactory cycle stability of 85.5% after 2000 cycles at 2 A g−1. This work shows a promising material applied in supercapacitors.

Ni/Co-MOFs derived NiS2/Co3S4 heterostructured microspheres for high-performance asymmetric supercapacitors

Despite the relatively mature state with respect to the technology for synthesizing transition metal sulfide structure, preparation of heterostructured transition metal sulfides with superior structure and high specific capacitance is still challenging. Herein, we prepared NiS2/Co3S4 heterostructured microspheres by the two-part hydrothermal method using bimetallic MOFs as precursors. By constructing this heterostructure, we aimed to modify the electronic structure of electrode materials to enhance the electrochemical performance. We did not need carbonization in the preparation process and showed good electrochemical properties with a great appearance. Experimental and characterization analysis demonstrated the successful synthesis of NiS2/Co3S4 heterostructured microspheres. The NiS2/Co3S4 electrode manifests a specific capacity of 252.3 mAh/g at 1 A/g. Furthermore, the hybrid asymmetric supercapacitor with NiS2/Co3S4 as the positive electrode has the energy density of 4.29 Wh kg−1 at the power density of 61.99 W kg−1 according to the stack volume. These heterostructured mixed metal sulfide electrode materials with high specific capacity and high rate provide new ideas for research.

Vertically aligned graphene-MXene nanosheets based electrodes for high electrochemical performance asymmetric supercapacitor

Vertically aligned porous morphologies have attracted much attention due to their long-range ordered channel structures. Here, a novel 3D vertically aligned graphene-MXene nanosheets based electrochemical supercapacitor is designed. Graphene oxide and Ti3C2TX MXene are used to prepare a vertically aligned porous bridge substrate (the pore size of 7 μm) by an ice template directional solidification method. Polyaniline nanowire arrays (PANI NWAs) are in-situ grown on the substrate by a polymerization process (positive electrode) and the substrate with more MXene is used as the negative electrode. After assembling into an asymmetric supercapacitor (ASC), the vertically aligned porous morphology is conducive to accelerating the directional transport of ions, which obviously improves the electrochemical properties of the ASC. The calculated specific capacitance of the ASC is 108F/g (at 1 A/g). The energy density of the ASC can reach 38 Wh/kg (at the power density of 810 W/kg) and the cycle stability is 82 % after 10, 000 cycles at 10 A/g.

Fabrication of controllable electrode materials MnOx-PTh for high-performance asymmetric supercapacitors

Aiming at the structure instability of polythiophene (PTh) caused by expansion/contraction in the processes of charging and discharging leading to the loss of capacitance after moderate cycling, the combination of transition metal oxides (TMOs) obtained from metal-organic frameworks (MOFs) and PTh in electrode materials is applied to overcome the limitations. TMOs/PTh composite electrode materials were successfully synthesized using Mn-MOF as a sacrificial template through in-situ growth of PTh using electrodeposition method. This method not only effectively mitigated the volumetric changes of TMOs but also prevented the loss of active species. In a three-electrode system, the MnOx-PTh-2 composite demonstrated exceptional specific capacitance of 602.5 F·g−1 at a current density of 1 A·g−1, along with excellent cycling stability with a capacitance retention rate of 83.2% even after 10,000 charge-discharge cycles under high current density. It was because that MnOx-PTh-2 exhibited lower resistance of charge transfer and resistance of diffusion. Furthermore, the synergistic effect of the composite material enhanced the ability for charge transfer, facilitated the dynamic response of ions, and enabled rapid ion transport. In addition, the MnOx-PTh-2 electrode predominantly operated under diffusion-controlled processes, and the pseudocapacitive properties of PTh facilitated the diffusion-control behavior of MnOx, thereby enhancing the ion-electrode interaction and improving the electrochemical performance of the material. Similarly, the asymmetric supercapacitor (MnOx-PTh-2//AC) assembled with the positive electrode of MnOx-PTh-2 and the negative electrode of activated carbon (AC)exhibited an energy density of 41.5 Wh·kg−1 when the power density was 498 W·kg−1. Additionally, it maintained 80.2% capacitance retention after 5000 cycles.

High-performance flexible asymmetric supercapacitors based on Hy-NiCoS/CNTs composites on porous graphene films

This research focused on the synthesized NiCoS/CNT composites by a hydrothermal method using thiourea and then drop-cast on laser-induced graphene (LIG) with porous structures for an active electrode of flexible asymmetric supercapacitors. Surface topography, cross-sectional outline, chemical structure and properties, and electrical properties of LIG, NiCoS, and Hy-NiCoS materials were measured and analyzed. In the two-electrode device, the Hy-NiCoS electrode has a high areal capacitance of 817 mF/cm2 under 0.5 mA/cm2 current density and a low internal resistance of 5.19 Ω. Furthermore, the prepared flexible asymmetric supercapacitors (Hy-NiCoS/AC) demonstrated excellent energy density of 0.017 mWh/cm2, power density of 3.2 mW/cm2, and areal capacitance of 85 mF/cm2 under 0.5 mA/cm2 current density. When the bending angles were 0°, 45°, and 90°, the areal capacitances of the prepared flexible asymmetric supercapacitors were 77.7, 75.0, and 70.8 mF/cm2, respectively. There is no obvious capacitance decay even at a large bending angle of 90°, which means that the asymmetric supercapacitor has excellent flexibility and stability. Based on the flexible asymmetric supercapacitors with excellent electrochemical performance, the proposed supercapacitors can be widely used in wearable electronic devices and healthcare products.