High-performance Supercapacitor Applications Research Articles

Ternary MXene/PANI/ZnO-based composite with a built-in p–n heterojunction for high-performance supercapacitor applications

Abstract Two-dimensional (2D) Ti3C2T x MXene-based materials have attracted widespread attraction in the field of energy storage owing to their high conductivity and accordion-like structure. However, challenges such as restacking and oxidative degradation of the Ti3C2T x MXene structure lead to poor stability, low conductivity, low specific capacitance and, consequently, a low specific energy, hindering their extensive adoption at an industrial scale. In this study, a ternary MXene/polyaniline (PANI)/ZnO (MPZ) composite has been synthesized via surface engineering of two-dimensional (2D) MXene using one-dimensional (1D) PANI nanowires and ZnO nanoparticles to enhance its specific energy and stability while sustaining its specific power. 1D PANI nanowires and ZnO nanoparticles act as spacers to prevent restacking, while also exposing the suppressed redox active sites of 2D MXene and preventing it from being oxidized by forming a porous conductive network all over the surface of the MXene. PANI and ZnO also provide additional electroactive redox sites by forming p–n heterojunctions, thus enhancing faradaic redox reactions and the specific capacitance of the MPZ composite. As a result, the overall electrochemical performance and stability of the ternary MPZ composite are enhanced due to the synergistic interactions among the individual components within the ternary MPZ composite. At a low current density of 0.1 A g−1, the ternary MPZ composite exhibited a maximum specific capacitance of 651.96 F g−1 and a highest specific energy of 32.59 Wh Kg−1 while maintaining a specific power of 60 W Kg−1 as compared to MXene and binary MP composite. Furthermore, it showcased exceptional cyclic stability over 10 000 cycles with 94.75% and 92.95% capacitive retention at 0.6 A g−1 current density and 40 mV s−1 scan rate, respectively. Thus, this current study highlights an effective strategy to enhance the specific energy of MXene-based supercapacitors through surface engineering and the construction of p–n heterojunctions within the composite.

Facile synthesis and first principles calculations of Li-MoS2/rGO nanocomposite for high-performance supercapacitor applications

Two-dimensional (2D) nanostructured materials such as graphene oxide nanosheets and molybdenum disulfide (MoS2) are potential candidates for electrochemical energy storage applications. The layered structure of MoS2 makes it a promising active electrode material for supercapacitors. Lithium (Li) interacted with MoS2/reduced graphene oxide (Li-MoS2/rGO) nanocomposite has been synthesized in two steps using a sonochemical dispersion method, and a one-pot hydrothermal method resulting in few-layered MoS2/rGO nanosheets of 2D heterointerfaces. The Li-MoS2/rGO nanocomposite exhibits a high specific capacitance of 173.3 F g−1 at a current density of 1 A g−1. Furthermore, an asymmetric supercapacitor device fabricated with Li-MoS2/rGO achieves a good energy density of 10.6 Wh kg−1 at a power density of 686.3 W kg−1 and outstanding cycling stability with 81.2 % capacity retention over 10,000 cycles. The dispersion of 2D-MoS2 in water is due to the strong electrostatic interface. The structural and electronic properties are theoretically calculated for pristine and Li-interacted MoS2/rGO heterostructure using density functional theory. A comparison of the density of states plots of the two heterostructures and the difference charge density plot of Li-MoS2/rGO heterostructure clearly brings out the importance of the presence of Li. A value of 64 μF cm−2 for the quantum capacitance for pristine MoS2/graphene heterostructure increases to a value 99 μF cm−2 corroborating the experimental observations and we assign this change to the transfer of charge from the Li atom to the outer S atoms in the MoS2/graphene heterostructure. This comprehensive approach, combining experimental synthesis with computational modelling, significantly advances the development and optimization of high-performance supercapacitor materials in the energy storage field. The Li-MoS2/rGO nanocomposite has excellent electrochemical specific capacitance and long-term cyclic stability and has been effectively used for supercapacitor applications with high electrochemical performance.

Preparation of Tectona grandis Leaves derived Activated Carbon for High-Performance Supercapacitor Application

In energy-based applications, biomass porous micro/nanostructures activated carbon materials are the significant candidates, because of their high specific surface area, superior electrical conductivity, affordability and environmental friendliness. In this work, the activated carbon was prepared from Tectona grandis leaves as a biomass, and thus activated by 25% K2CO3 solution. The prepared carbon was designated as TGLAC. Second carbon was prepared from TGLAC was doped with urea and named as N-doped TGLAC. The physico-chemical analytical methods were employed to access the phase structure, bonding nature and morphological properties of the freshly prepared activated carbon material. Three electrode systems were utilized to estimate the supercapacitor features in 1 M Na2SO4 electrolyte. The prepared activated carbon electrode provides a specific capacitance of 371 F g–1 at 1 A g–1 and a 62% rate capability at 5 A g–1. It retains 94% of its initial capacitance during the cyclic stability analysis at 5 A g–1 over 5,000 cycles. This study demonstrates that carbon based materials obtained from sustainable waste biomass can exhibit favourable electrochemical performance in energy applications, providing a clear and feasible synthetic approach and strategy for their utilization.

Food waste-derived activated carbon for supercapacitors

This research investigates the utilization of activated carbon synthesized from food waste biomass, specifically, peels of orange, apple, cucumber, and onion, as electrode materials for high-performance supercapacitor applications. The peels were first pre-carbonized at 600 °C and then activated at 700 °C with KOH. The research involved developing a supercapacitor using the synthesized activated carbon as the electrode material and 6 M KOH as the electrolyte. The results indicated that electrodes made from orange peel, apple peel, cucumber peel, and onion peel exhibited specific capacitances of 238.5 F/g, 201.2 F/g, 236.9 F/g, and 118.9 F/g, respectively, at a current density of 1 A/g. When the current density was increased to 2 A/g, the elec-trodes maintained up to 90% of their capacitance.

Solid-state synthesis of nickel selenide for high-performance supercapacitors

This study focuses on the synthesis and electrochemical characterization of nickel diselenide (NiSe2) as a promising electrode material for supercapacitors. NiSe2 was synthesized through a facile solid-state process involving the mixing of nickel acetylacetonate and selenous acid, followed by drying and sintering at 500 °C under inert conditions. The resulting NiSe2 exhibited a granular structure with worm-like surface architecture and particle size ranging from 20 to 100 nm. The electrochemical performance of NiSe2 was evaluated using cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), and electrochemical impedance spectroscopy (EIS) in a 6 M KOH electrolyte. NiSe2 demonstrated a high specific capacitance of 744.7 F g−1 at a discharge rate of 1 A g−1, with an outstanding rate capability retaining the capacitance of 483.6 F g−1 at 10 A g−1, and exceptional long-term cycling stability. The kinetic analysis revealed that the energy storage mechanism in NiSe2 primarily involves diffusion-controlled charge storage. EIS further confirmed the favorable charge transfer properties of the NiSe2 electrode. Overall, NiSe2 synthesized via the proposed method shows great promise for application in high-performance supercapacitors.

Electrochemical evaluation of ZnO and PAN-based carbon nanofibers composite for high-performance supercapacitor application

Electrochemical evaluation of ZnO and PAN-based carbon nanofibers composite for high-performance supercapacitor application

MnCo2O4 nanospheres entrapped in g-C3N4 network for High-Performance supercapacitor applications

MnCo2O4 nanospheres were embedded in a g-C3N4 network using the solvothermal method with ethylene glycol as the solvent. SEM confirmed the uniformity of the MnCo2O4/g-C3N4 nanospheres, while XRD and XPS were used for structural and elemental analysis, including metal oxidation states. BET analysis revealed the surface area and porosity, while TEM analysis provided information on the interplanar spacing and morphology. Electrochemical evaluations using CV, GCD, and EIS demonstrated that the 2D g-C3N4 nanosheets interwoven with MnCo2O4 nanospheres have excellent specific capacities (654 Fg−1 at 2 Ag−1) and power densities (1521.2 W/kg at 7 Ag−1). The electrode material shows superior cyclic stability with 92.3 % capacitance retention after 5000 cycles.

Polar phonons features and intrinsic dielectric properties of RE2CoMnO6 (RE = Tb, Dy, Ho, Tm and Yb) double perovskites

RE-based double perovskite (DP) oxides of the RE₂TMTM'O₆ family exhibit intriguing magnetodielectric (MD) properties and magnetocaloric effects (MCEs), making them promising candidates for applications in high-performance supercapacitors, memories, spintronic devices, and cryogenic magnetic refrigeration. This paper addresses the vibrational properties of RE2CoMnO6 (RE = Tb, Dy, Ho, Tm, and Yb) ceramics for the first time using infrared reflectance spectroscopy. The dielectric merit factors in the microwave (MW) range, including the quality factor (Qu) and the static dielectric constant (ɛ0), were estimated. It was observed that the intrinsic dielectric constants decrease from approximately 26.2 to 14.4 as the rare earth ionic radius decreases. The mean values of these compounds suggest their suitability for applications in MW circuitry devices.

Capacity augmentation strategy in α-Fe2O3 nanoparticles through multifaceted structural and electrochemical analyses

Hematite (α-Fe₂O₃) has garnered significant research interest for supercapacitor applications, but capacity fading and limited cyclic life remain serious challenges. In this context, the present research provides a comprehensive study of the factors that significantly impact charge kinetics within the electrode and at the solid/electrolyte interface. By integrating structural and electrochemical analyses, this study offers an effective strategy to enhance the capacity of α-Fe₂O₃ nanoparticles through rigorous scientific analysis and identification of various qualitative and quantitative factors that influence charge storage capacity. A simple one-step co-precipitation method was adopted to synthesize porous α-Fe₂O₃ nanoparticles. The quantitative analysis of charge kinetics demonstrated the domination of diffusion-controlled charge storage as the main contributor to the total charge storage. The α-Fe₂O₃ nanoparticles-based electrode delivered a high energy density of 24.6 Wh kg⁻1 at an impressive power density of 478.7 W kg⁻1. Additionally, it displayed a capacity retention of 79 % over 10,000 cycle operations. The choice of electrode material and the superior porous nanoarchitecture have proven to be advantageous for high-performance supercapacitor applications, offering fast electron/ion transport.

MOF-on-MOF Derived Co2P/Ni2P Heterostructures for High-Performance Supercapacitors.

Metal-organic frameworks (MOFs) have been widely used as versatile precursors to fabricate functional nanomaterials with well-defined structures for various applications. Herein, the presynthesized Ni-MOF nanosheets were grown on a Ni foam (NF) substrate, which then guided the nucleation and further growth of Prussian blue analogues (PBA) nanocubes to form MOF-on-MOF of the PBA/Ni-MOF film. This film was subsequently converted into a Co2P/Ni2P heterostructure. The NF-supported Co2P/Ni2P composites exhibited excellent supercapacitor performance, delivering a high specific capacity of 5124.2 mF cm-2 at 1 mA cm-2 and a remarkable capacity retention of 80.69% after 3000 cycles at 10 mA cm-2. An asymmetric supercapacitor assembled using Co2P/Ni2P/NF as the cathode and activated carbon as the anode yielded a maximum energy density of 0.34 mWh cm-2 at a power density of 1.50 mW cm-2. The enhanced supercapacitor performance is attributed to the synergistic effects of the Ni2P and Co2P components with multiple valence states as well as the unique hierarchical structure, which provides efficient pathways for electron and ion transport while mitigating volume expansion during energy storage. This synthetic strategy demonstrates an effective approach to fabricate phosphide-based hybrid materials for high-performance supercapacitor applications.

MoS2/Yb, Er-doped CeO2 composite synthesized by hydrothermal method for high-performance supercapacitor applications

MoS2/Yb, Er-doped CeO2 composite synthesized by hydrothermal method for high-performance supercapacitor applications

Preparation of N and S heteroatoms doped activated carbon from stalks of Gossypium hirsutum L. flower for high-performance symmetric supercapacitor application

Preparation of N and S heteroatoms doped activated carbon from stalks of Gossypium hirsutum L. flower for high-performance symmetric supercapacitor application

One-dimensional lepidocrocite titania mesoparticles integrated with activated carbon for high-performance supercapacitor applications

Herein, we mix titania-based, TiO2, porous mesostructured, comprised of one-dimensional lepidocrocite nanofilaments, 1DLs, ≈ 5 × 7 Å2 in cross-section, with activated carbon, AC, to create unique composite structures with exceptional electrochemical properties. The synthesis method is facile, cost-effective, and scalable. While the porous mesoparticles, PMs, possess excellent protonic conductivity and exhibit enhanced faradic behavior in acidic aqueous media, their low electronic conductivity restricts their power output. The problem is solved by mixing the PMs with AC powders with various loadings. Electrolytes used were sulfuric acid, H2SO4, potassium hydroxide, KOH, lithium and Na-sulphates. The best PM loading was found to be 25 wt%. The resulting composite exhibits a specific capacitance (capacity) of 1024 Fg−1 (554 mAhg−1) at a 2 mVs−1 scan rate, with 97 % cyclic stability over 10,000 cycles when the electrolyte was 1 M H2SO4. Upon integration into a symmetrical device, the composite exhibited a specific energy of 135 Whkg−1 at 0.5 Ag−1. Further, it demonstrated a peak specific power of 18 kWkg−1, while retaining a specific energy of 54 Whkg−1 at 5 Ag−1. Notably, following 100,000 cycles at 1 Ag−1, the symmetrical cell sustained approximately 50 % of its initial specific capacitance. Subsequently, a 24 h self-discharge test revealed a decrease in cell voltage from 1.95 V to 0.48 V, thereby highlighting the potential suitability of these supercapacitors for short-term energy storage applications.

Synergistic Schottky contacts & diatomic doping in Cr/P-MoS2@Ti3C2Tx with boosted energy storage performance

Molybdenum disulfide (MoS2), despite its promising attributes, suffers from low conductivity and aggregation. Herein, we introduce a novel approach that integrates Schottky contacts with Cr/P diatomic doping in MoS2@Ti3C2Tx, significantly enhancing its performance. The Schottky contacts effectively suppress aggregation and accelerate interfacial charge transfer, while Cr/P doping boosts conductivity, active sites, and stability. As a result, the Cr/P-MoS2@Ti3C2Tx electrode exhibits a specific capacitance of 650 F g-1 at 1 A g-1, which is fourfold higher than that of pristine MoS2. When assembled into an asymmetric supercapacitor (Cr/P-MoS2@Ti3C2Tx//AC ASC), the device achieves a peak energy density of 32 Wh kg-1 at 303 W kg-1, maintaining 85% capacitance retention after 10,000 cycles with an impressive coulombic efficiency of 97%. Furthermore, the density functional theory (DFT) calculations validate the beneficial effects of Schottky contacts and diatomic doping on the improved energy storage performance of Cr/P-MoS2@Ti3C2Tx. This work demonstrates the promising potential of the material for applications in high-performance supercapacitors (SCs).

Marigold flower-like structured battery-type Cu2O/Co(OH)2 composite electrode material for high-performance supercapacitors

Addressing the limitations of individual Cu2O and Co(OH)2 components, this study aims to develop a high-performance supercapacitor electrode by synergistically combining these materials. A composite electrode material of Cu2O/Co(OH)2 was effectively synthesized on nickel foam via a facile hydrothermal method for supercapacitor applications. The as-fabricated Cu2O/Co(OH)2 composite electrode exhibits a hierarchical marigold flower-like morphology that comprises of many interspersed nanoflakes. This unique morphology offers several advantages, including increased surface area, abundant electroactive sites, and enhanced electrolyte accessibility, all of which contribute to superior electrochemical performance. The Cu2O/Co(OH)2 electrode demonstrates exceptional battery-type supercapacitor behavior, characterized by prominent redox peaks in cyclic voltammetry curves and a well-defined potential plateau during galvanostatic charge-discharge measurements. The electrode delivers an outstanding specific capacitance of 90.21 mA h g⁻1 at a current density of 1.25 A g⁻1 and retains a remarkable 81.91 % capacitance at a high current density of 12.5 A g⁻1. Furthermore, the electrode exhibits impressive cycling stability, maintaining approximately 107.84 % of its initial specific capacity value after 200 cycles at 7.5 A g⁻1. Electrochemical impedance spectroscopy measurements reveal low solution resistance and charge-transfer resistance, signifying efficient charge-transfer kinetics within the electrode. These findings highlight the potential of Cu2O/Co(OH)2 composite electrodes as promising candidates for high-performance supercapacitor applications.

High Performance MXene/MnCo2O4 Supercapacitor Device for Powering Small Robotics.

The development of advanced energy storage devices is critical for various applications including robotics and portable electronics. The energy storage field faces significant challenges in designing devices that can operate effectively for extended periods while maintaining exceptional electrochemical performance. Supercapacitors, which bridge the gap between batteries and conventional capacitors, offer a promising solution due to their high power density and rapid charge-discharge capabilities. This study focuses on the fabrication and evaluation of a MXene/MnCo2O4 nanocomposite supercapacitor electrode using a simple and cost-effective electrodeposition method on a copper substrate. The MXene/MnCo2O4 nanocomposite exhibits superior electrochemical properties, including a specific capacitance of 668 F g-1, high energy density (35 Wh kg-1), and excellent cycling stability (94.6% retention over 5000 cycles). The combination of MXene and MnCo2O4 enhances the redox activity, electronic conductivity, and structural integrity of the electrode. An asymmetric supercapacitor device, incorporating MXene/MnCo2O4 as the positive electrode and Bi2O3 as the negative electrode, demonstrates remarkable performance in powering small robotics and small electronics. This work underscores the potential of MXene-based nanocomposites for high-performance supercapacitor applications, paving the way for future advancements in energy storage technologies.

α-Bi2O3 tubular rods coated on Bi2O2CO3 nanosheets for high-performance asymmetric supercapacitor applications

Mixed phases of bismuth oxide nanostructures as an active electrode material in supercapacitor applications have recently gained huge research interest. In this study, the layered Bi2O2CO3 nanosheets and the secondary phase of α-Bi2O3 tubular rods named Bi2O2CO3/α-Bi2O3 heterostructure have been synthesized and utilized for supercapacitor applications. The crystal nature and microstructure of the Bi2O2CO3/α-Bi2O3 heterostructure were initially confirmed by powder X-ray diffraction (p-XRD), Raman, UV-Vis diffuse reflectance spectroscopy (UV-DRS, absorbance), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) studies. X-ray photoelectron spectroscopy (XPS) measurements have investigated the oxidation states and chemical binding energies. Regarding the electrochemical performances, the Bi2O2CO3/α-Bi2O3 heterostructure as electro-active material delivered a maximum specific capacitance (Cs) value of 635 F g−1 at the given current density value of 1 A g−1 in a conventional three-electrode mode. A coin cell type electrode has been fabricated using Bi2O2CO3/α-Bi2O3 heterostructure, resulting in an asymmetric supercapacitor device cell (ASC), which has a Cs of 112 F g− 1 (at 1 A g− 1) and a power density and energy density values of 515 W kg−1 and 22.5 Wh kg−1 respectively. The two supercapacitor electrodes in sequence effectively ignite the red-light-emitting diode (LED). Moreover, in the ASC type Bi2O2CO3 /α-Bi2O3 heterostructure, the specific capacitance value was slightly reduced to 12.3 % by 2000 cycles, showing favourable cyclic performance and stability during the electrochemical process. Based on the above-mentioned characterization, the appropriate electrochemical performances of Bi2O2CO3/α-Bi2O3 tubular rod heterostructures make them a promising candidate for future energy storage devices.

MgOMo2C/multiwalled carbon nanotube composite for high-performance supercapacitor applications

Magnesium molybdate (MgMoO4) nanostructure has been successfully prepared and employed as a catalyst for the production of multi-walled carbon nanotubes (CNTs) by the chemical vapor deposition method. The prepared nanostructure materials are characterized through XRD, TEM, FTIR, BET and Raman spectroscopy. The XRD results and TEM images confirm the formation of the plate-like MgMoO4 structure, as well as the existence of Mo2C and CNTs in the type of bundles structure (CNTBs). The high dispersion and stability of Mo nanoparticles in the composite of plate-like MgMoO4 is responsible for the formation of CNTBs with uniform diameters. Thus, the plate-like MgMoO4 nanoparticles and the MgOMo2C@CNTBs hybrid material are assessed as electrodes in a supercapacitor device for the first time. The produced hybrid supercapacitor MgOMo2C@CNTBs has a good specific capacitance (354 F g−1) and strong cycling stability (82 percent capacity retention over 2000 cycles)

Graphene oxide from coconut shells for high-performance supercapacitor application

Globally, the demand for materials with high ultrafast charge rates yet slow discharge continues to rise which has resulted in extensive research into supercapacitors. Although the current supercapacitors can meet such demands, the high processing cost coupled with the use of toxic chemicals remains a major concern. In this study, porous graphene oxide (GO) with a unique morphology was synthesized by an improved Tour’s method for supercapacitor application using coconut shells as a precursor. The structure of the synthesized material consists of partially graphitized walls of porous GO. The surface morphology, the defects created in the GO, and the specific surface area of the as-synthesized materials were studied. When evaluated as an electrode material for supercapacitors, a specific capacitance of 173 F/g at 0.5 A/g in 0.5 M Na2SO4 and 139 F/g at 0.5 A/g in 2 M KOH was recorded. Moreover, a high capacitance retention of 99.3% was recorded after 1000 cycles, confirming the good cyclic stability of the synthesized electrode material. The good electrochemical performance can be attributed to the electrode material’s intrinsic structural and compositional superiorities. These findings indicate the potential of using coconut shells as a precursor for the synthesis of high-performance graphene-based supercapacitor electrodes with improved cost-effectiveness and reduced environmental impact.

Co-precipitation Synthesis and Characterization Studies of Manganese Oxide Doped with Nickel for High-Performance Energy Storage Supercapacitor Application

The advancement in nanotechnology research has facilitated the development of eco-friendly methods for the synthesis of nanoparticles. In this work, nickel (Ni)-doped manganese oxide was synthesized using the co-precipitation method. The prepared Ni-doped manganese oxide products have been characterized by X-ray powder diffraction, scanning electron microscopy (SEM), transmission electron microscope (TEM), and energy dispersive X-ray spectroscopy (EDS). The preliminary electrochemical characteristics include charge-discharge cycling, which improves the conductivity and capacitance of the high-performance aqueous asymmetrical supercapacitor. The CV analysis of the Ni-doped manganese oxide electrode demonstrated a distinctive pseudocapacitive behavior in 1 M KOH solution. The nickel (Ni) doped electrode has a higher specific capacitance value than the pure manganese oxide electrode, with a value of 2225.07 F×g-1 at a scan rate of 5 mV×s-1. Keywords: Supercapacitor, Co-precipitation method, Nanotechnology, Synthesized, Electrochemical