Materials For Supercapacitors Research Articles

Metal–organic frameworks and their composites: Design, synthesis, properties, and energy storage applications

Porous crystalline metal–organic frameworks (MOFs) are promising materials for supercapacitors (SCs) owing to their excellent pore structures, large surface areas, adjustable topological types, and multivalent active metal nodes, which endow them with ideal energy-storage performance. However, despite their successful application in many fields such as catalysis, gas adsorption and separation, and sensors, various intrinsic defects have hindered their practical application in SCs. In recent years, MOFs have demonstrated significant advancements in their electrochemical performance, and their applications in SCs have been gaining momentum. This review summarizes the design, classification, synthesis strategies, and properties of MOFs. The formation conditions and mechanisms of MOFs are discussed and the effects of the different types and synthesis strategies of MOFs on their properties are compared to improve their design and preparation. The research progress on pristine MOFs and their composites in SCs is reviewed, highlighting the solutions for the intrinsic defects in pristine MOFs in SC applications. The challenges of utilizing MOF-based materials in SC applications are summarized and potential solutions for their future development are suggested.

Synthesis of ZnO and NiO nano ceramics composite high-performance supercapacitor and its catalytic capabilities

NiO and ZnO mixed nanocomposites were manufactured using the solution combustion process. As-prepared samples were analyzed using XRD. The XRD shows an average crystallite size of 35–40 nm. The elemental composition determined by EDS indicates a nearly equal proportion of Ni and Zn, with an atomic ratio of Ni/Zn = 0.96. The specific capacitances of NiO is 295.5 Fg-1, ZnO is 117.3 Fg-1 and ZnO/NiO nanocomposites is 561.75 Fg-1 which are more than NiO and ZnO alone. This study shows that constructing binary oxide nanocomposites is an approach for developing high-performance supercapacitor electrode materials. Experimental observations on catalytic activity revealed that NiO/ZnO increased catalytic activity. Furthermore, adding NiO to ZnO in the composite increased the overall amount of oxygen vacancies in the samples. Our research lays the door for a simple, inexpensive, nontoxic, and quick technique to synthesize binary transition metal oxide-based electrode materials for high-performance supercapacitors.

Enhanced Performance of Laser-Induced Graphene Supercapacitors via Integration with Candle-Soot Nanoparticles.

Laser-induced graphene (LIG) has been emerging as a promising electrode material for supercapacitors due to its cost-effective and straightforward fabrication approach. However, LIG-based supercapacitors still face challenges with limited capacitance and stability. To overcome these limitations, in this work, we present a novel, cost-effective, and facile fabrication approach by integrating LIG materials with candle-soot nanoparticles. The composite electrode is fabricated by laser irradiation on a Kapton sheet to generate LIG material, followed by spray-coating with candle-soot nanoparticles and annealing. Materials characterization reveals that the annealing process enables a robust connection between the nanoparticles and the LIG materials and enhances nanoparticle graphitization. The prepared supercapacitor yields a maximum specific capacitance of 15.1 mF/cm2 at 0.1 mA/cm2, with a maximum energy density of 2.1 μWh/cm2 and a power density of 50 μW/cm2. Notably, the synergistic activity of candle soot and LIG surpasses the performances of previously reported LIG-based supercapacitors. Furthermore, the cyclic stability of the device demonstrates excellent capacitance retention of 80% and Coulombic efficiency of 100% over 10000 cycles.

Facile electrodeposition of CoMn2O4 nanoparticles on nickel foam as an electrode material for supercapacitors

In this study, we successfully utilized nickel foam (NF) as a scaffold for the direct deposition of ultra-thin CoMn₂O₄ (CMOs) through a one-step electrochemical deposition method. This was followed by annealing to produce a stable, free-standing electrode. This electrode was then used to develop an aqueous asymmetric supercapacitor (AASC). The optimized electrode demonstrated an exceptionally high specific capacitance of 2218.32 F g−1 at 1 A g−1 and excellent cyclic stability, retaining 86.67 % of its capacitance after 6000 cycles. An AASC device was also constructed, employing CMOs on NF as the cathode and commercially available activated carbon (AC) on carbon cloth (CC) as the anode. This configuration achieved a high energy density of 83.85 Wh kg−1 at a power density of 800.03 W kg−1, with robust cycling stability (∼87.16 % retention after 16,000 cycles at 30.0 A g−1) and nearly 100 % Coulombic efficiency. These results surpass those of many state-of-the-art supercapacitors (SCs), highlighting the significant potential for practical applications.

Enhanced electrochemical validation of metal organic frameworks-derived TiO2/Fe-TiO2 as an active electrode for supercapacitors

Developing supercapacitor materials that are both efficient and durable, with high cycle life and specific energy, poses a significant challenge due to issues in electrodes such as volume expansion and electrode degradation that occur over time. This work reports a simple, novel, and cost-effective synthesis method to fabricate high surface area “Iron (Fe) doped TiO2 materials” via the metal-organic framework (MOF) route for supercapacitor application. Morphological analysis revealed a disc-like shaped pattern for pristine TiO2 (PT), and a cuboid form for Fe-doped TiO2 (FeT). The electrochemical investigation of MOF-derived PT and FeT electrode materials demonstrated the superior performance of FeT. Cyclic Voltammetry revealed enhanced electrochemical properties in FeT. Galvanostatic charge-discharge measurements confirmed FeT’s higher energy storage capacity, reaching a maximum specific capacitance of 925 Fg− 1. Long-term cycling tests exhibited excellent stability, with FeT retaining 67% of its initial capacitance after 6000 cycles and showing prolonged self-discharge. Overall, the results underscore the potential of Fe-doped TiO2 for high-performance supercapacitors.

Novel three-dimensional architectured ZnMgAl ternary layered double hydroxide@reduced graphene oxide nanocomposites as electrode material for high-performance supercapacitor

Ternary layered double hydroxides (LDH) have recently attracted immense attention owing to their stupendous features, such as fine compositional tuning, multiple valence states, and superior electrochemical activity. Moreover, their intriguing structures and distinctive physiochemical properties delineate them as an exemplary material to serve as electrodes for high-performance supercapacitors (SCs). The present work reports the in-situ synthesis of Zinc Magnesium Aluminium LDH (ZMA) integrated with reduced graphene oxide (rGO) through a single-step hydrothermal approach. The resulting novel ternary ZMA@rGO nanocomposite (ZMAG) possesses a unique architecture incorporating hierarchical 3D nanoflowers of ZMA embedded on graphene nanosheets. The porous morphology of LDH improves interfacial charge transport, which results in more faradaic reactions at the electrochemically active sites. In addition, the conductive graphene nanosheets render a high specific surface area, endowing excellent capacitive behavior. The amalgamated electrochemical properties of ZMA and rGO develop a competent electrode material (ZMAG) for SCs. The ZMAG2 nanocomposite having ZMA and rGO in 1:1, evinces a specific capacitance (Cs) of 656.7 F/g at a current density (Id) of 1 A/g. Furthermore, the asymmetric supercapacitor (ASC) features admirable cycle stability (retains 89% of initial capacitance after 15,000 charge/discharge cycles). Herein, the real-time application of ZMA@rGO//AC ASC has also been demonstrated. Therefore, hierarchical porous nanostructure proclaims new prospects for fabricating proficient electrode materials for energy storage devices.

Aftermath of Ag embedding on structural, optical, and supercapacitor electrode attributes of USP-grown CuO thin films

Here, ultrasonic spray pyrolysis method (USP) was utilized to produce pure and silver doped copper oxide nanostructures on glass substrates. Thereafter, several characterization techniques were conducted on the grown samples to delve into their morphological, structural, electrochemical, and optical aspects. The mentioned analyses were carried out by performing x-ray photoelectron spectroscopy, scanning electron microscope, X-ray diffraction, electrochemical impedance spectroscopy, galvostatic charge-discharge, cyclic voltammetry, and UV–visible spectroscopy measurements. Thus, the impact of silver impurity doping on the relevant aspects of host material were recorded as well as the features of unspoiled copper oxide films. Accordingly, the samples, as indicated by X-ray diffraction results, possessed (002) preferential plane orientation of copper oxide material along with the crystallite sizes ranging from 52.52 nm to 75.02 nm due to the imperfections caused by the silver doping. The scanning electron microscope images exhibited that the silver doping did not form significant modifications in the host material morphology where nanowire-like structures observed. The presence of the suggested materials in the films was verified by the x-ray photoelectron spectroscopy. Also, the UV–visible spectroscopy measurements detected that optical absorbance edge and bandgap energy values red shifted as a result of the impurity doping. The electrochemical supercapacitors performances of the silver doped copper oxide nanostructured thin films were inspected by using the GCD, EIS, and CV. The silver doped copper oxide films demonstrated a specific capacitance value of 66 F/g at a current density of 1 A/g in 1 M KOH electrolyte. From Nyquist plot, Rs, Rcor, Rpo, Ccor and Cc were obtained as 2.327 × 103 Ω.cm2, 43.63 × 103 Ω.cm2, 4.580 × 103 Ω.cm2, 111.5 × 10-6 S*s^a. cm-2 and 101.1 × 10-6 S*s^a. cm-2, respectively. The results indicated that the electrochemically synthesized the silver doped copper oxide electrodes can be obtained and developed as an alternative electrode material for supercapacitors (SCs).

Morphology Modulation of ZnMn2O4 Nanoparticles Deposited In Situ on Carbon Cloth for Supercapacitors

As a typical spinel structure material, ZnMn2O4 has been widely researched in the field of electrode materials. However, ZnMn2O4 nanoparticles as electrode materials for supercapacitors have the disadvantages of low conductivity, inferior structural integrity, and easy aggregation, resulting in unsatisfying electrochemical performance. In this work, we use a hydrothermal method and high-temperature calcination to deposit ZnMn2O4 nanoparticles on carbon cloth and explore the influence of hydrothermal reaction time on the deposition morphology and distribution of ZnMn2O4 nanoparticles on carbon cloth. The deposition process of ZnMn2O4 nanoparticles on carbon cloth was analyzed, and a ZMO-9 electrode was deduced to be the most suitable electrode for supercapacitors. A series of electrochemical performance tests show that the ZMO-9 electrode has excellent specific capacitance (specific capacity) (499 F·g−1 (299.4 C·g−1) at a current density of 1 A·g−1) and rate performance (75% capacitance retention at a current density of 12 A·g−1). The assembled asymmetric supercapacitor has an energy density of 46.6 Wh·kg−1 when the power density is 800.1 W·kg−1. This work provides a reference for the structural design of ZnMn2O4 supercapacitor electrode materials and the improvement of electrochemical properties.

Synthesis of GN/ MnO2 nanocomposite materials for photo-assisted supercapacitor with enhanced capacities

Supercapacitors with the advantages of high power density and rapid discharging rate have widespread applications in energy storage. Nevertheless, their development is hindered by the limitation of low specific capacity. Traditional approaches to enhance specific capacity primarily involve incorporating foreign atoms and blending with additional reactive substances. Herein, a photo-assisted supercapacitor electrode material (GN/MnO2 nanocomposite) with excellent capacity is developed. As a photoactive material, graphene generates electrons and holes with photoirradiation. As the photogenerated carriers increase, electrons are separated from the holes and stored as charges. Photoirradiation is the driving force that promotes the energy storage and conversion of supercapacitors. Although there are many reports on GN/MnO2 composites, there are still few reports on the photo-assisted energy storage of this composite material. The specific capacity of this photo-assisted GN/MnO2 electrode materials could reach 210 F/g with photoirradiation. It was higher than that without photoirradiation (170 F/g). The development of this study provides important theoretical guidance and practical significance for the research of photo-assisted energy storage materials, and plays a significant role in advancing the progress of energy storage devices with high specific capacity.

Bimetallic Manganese–Nickel Metal–Organic Framework Anchored Hexyl-Aminated Carbon Nanotube Hybrid as an Anodic Material for Solid-State Asymmetric Supercapacitors

Bimetallic Manganese–Nickel Metal–Organic Framework Anchored Hexyl-Aminated Carbon Nanotube Hybrid as an Anodic Material for Solid-State Asymmetric Supercapacitors

Carbon-modified NiCo2O4 as an electrode material for supercapacitors

Transition metal oxides are a promising class of electrode materials for pseudocapacitors due to their high electrochemical activity and eco-friendly nature. However, they possess poor intrinsic conductivity which results in the low energy density of the assembled supercapacitors. In this study, electrodes composed of amorphous C-modified NiCo2O4 (C/NiCo2O4/NF) on nickel foam substrate were prepared by electrochemical deposition and thermostatic heating method. The incorporation of amorphous C compensates for the low electrical conductivity of NiCo2O4 materials, thereby significantly enhancing the electrochemical performance. The galvanostatic charge-discharge (GCD) test results reveal an impressive specific capacitance of 379.4 mF/cm2 at a current density of 1.5 mA/cm2, and with a capacitance retention rate of 87.1 %. In addition, the symmetric supercapacitor assembled using C/NiCo2O4 electrode materials exhibits exceptional energy density and power density, reaching maximum values of 522.3 μWh/cm2 and 900 μW/cm2 respectively. The device is capable of illuminating LED for up to 8 min, further demonstrating its practical applicability. These results underscore the feasibility and promise of C/NiCo2O4 as an electrode material for the advancement of high-performance supercapacitors.

Optical and electrochemical analysis of nitrogen-doped carbon quantum dots from Moosa balbeesiaana peels for advanced supercapacitor applications

The demand for suitable electrode materials for energy storage devices, driven by increasing energy needs and environmental concerns, has led to the investigation of green synthesis methods. In this study, a composite material (rGO@NCQDs) comprising nitrogen-doped carbon quantum dots (NCQDs) derived from Moosa balbeesiaana peels and reduced graphene oxide (rGO) was synthesized via hydrothermal methods to evaluate its photophysical properties and electrochemical performance for supercapacitors applications. Additionally, the electrochemical behavior of rGONCQDs combined with Vanadium pentoxide (V2O5) was explored.Characterization techniques including FTIR spectroscopy revealed typical carbon-based material features in rGO-decorated NCQDs, and rGONCQDs@V2O5 composite. SEM analysis illustrated distinctive surface structures (mushroom-shaped for rGO@NCQDs and flowered-shaped for rGONCQDs@V2O5), while XRD confirmed crystalline structures with specific sizes.Photophysical investigations demonstrated significant Solvatochromic shifts and strong solute-solvent interactions in the composites. Electrochemical studies, including cyclic Voltammetry and Galvanostatic measurements, exhibited promising performance metrics. Specifically, rGO@NCQDs demonstrated a specific capacitance of 134.68 Fg−1 with excellent retention over 5000 charge-discharge cycles. In contrast, rGONCQDs@V2O5 exhibited a maximum specific capacitance of 562.62 Fg−1 at a scan rate of 10 mVs−1 and exceptional cycle stability (96 % retention over 5000 cycles).These findings highlight the potential of the synthesized composites as efficient electrode materials for supercapacitors, offering enhanced electrochemical performance and stability. The study underscores the importance of green synthesis approaches in developing functional materials for sustainable energy storage applications.

Controllable preparation of polymetallic selenides and their application in high-performance supercapacitors

Transition metal selenides (TMSes) have garnered considerable interest as potential electrode materials for supercapacitors owing to their promising electrochemical properties, but the fabrication of intricate nanostructured electrodes utilizing these compounds still poses a formidable challenge. In this study, a ternary transition metal selenide nanomaterial Cu2MnSnSe4, which has rarely been reported, was successfully synthesized on nickel foam (NF) by a simple solvothermal method, and its electrochemical properties have not been concern by researchers. We systematically studied the electrochemical properties of the materials synthesized under different solvothermal reaction times, and discussed the relationship between reaction time and electrochemical properties. The unique porous surface architecture of the sea urchin-like nanosphere configuration in Cu2MnSnSe4 material grants it a significantly enhanced specific surface area and a proliferation of electrochemically active sites, surpassing those of other comparable materials. According to the synthesis reaction time from short to long, the materials were named Cu2MnSnSe4-1 (20h), Cu2MnSnSe4-2 (25h) and Cu2MnSnSe4-3 (30h), among which Cu2MnSnSe4-2 showed better electrochemical performance than the other two. Electrochemical results show that the prepared Cu2MnSnSe4-2 electrode possesses an outstanding specific capacitance of 930.6 mF cm−2 at 2 mA cm−2, good rate performance (92 %), and a capacitance retention rate is 67.57 % after 3000 cycles of charging and discharging. The asymmetric supercapacitor (ASC) exhibits a voltage window spanning 0–1.6 V, reaching an outstanding energy density of 0.076 mWh cm−2 at 1.47 mW cm−2. Remarkably, it maintains 129.63 % cycling stability even after enduring 5000 charge-discharge cycles. From the above results, it can be seen that Cu2MnSnSe4 material may be a promising electrode material with broad application prospects in the practical application of supercapacitors.

Ni3V2O8 Marigold Structures with rGO Coating for Enhanced Supercapacitor Performance.

In this work, Ni3V2O8 (NVO) and Ni3V2O8-reduced graphene oxide (NVO-rGO) are synthesized hydrothermally, and their extensive structural, morphological, and electrochemical characterizations follow subsequently. The synthetic materials' crystalline structure was confirmed by X-ray diffraction (XRD), and its unique marigold-like morphology was observed by field emission scanning electron microscopy (FESEM). The chemical states of the elements were investigated via X-ray photoelectron spectroscopy (XPS). Electrochemical impedance spectroscopy (EIS), Galvanostatic charge-discharge (GCD), and cyclic voltammetry (CV) were used to assess the electrochemical performance. A specific capacitance of 132 F/g, an energy density of 5.04 Wh/kg, and a power density of 187 W/kg were demonstrated by Ni3V2O8-rGO. Key electrochemical characteristics were b = 0.67; a transfer coefficient of 0.52; a standard rate constant of 6.07 × 10-5 cm/S; a diffusion coefficient of 5.27 × 10-8 cm2/S; and a series resistance of 1.65 Ω. By employing Ni3V2O8-rGO and activated carbon, an asymmetric supercapacitor with a specific capacitance of 7.85 F/g, an energy density of 3.52 Wh/kg, and a power density of 225 W/kg was achieved. The series resistance increased from 4.27 Ω to 6.63 Ω during cyclic stability tests, which showed 99% columbic efficiency and 87% energy retention. The potential of Ni3V2O8-rGO as a high-performance electrode material for supercapacitors is highlighted by these findings.

Novel synthesis of B-doped Ti3C2Tx thin sheets via BF3 Lewis acid etching: Structural insights and Supercapacitor applications

The rising demand for energy storage spurs research on supercapacitor materials, valued for high-power density and long-term cycling, vital in industries. Among two-dimensional materials, MXene, with a general formula of Mn+1XnTx, where M represents early transition metals, X indicates C and/or N, Tx represents functionalized surface groups, and n = 1, 2, or 3, stands out as an ideal candidate for energy storage applications. Here, for the first time, we report the use of a Lewis acid, boron trifluoride (BF3), as an electron-deficient etchant in a sulfuric acid (H2SO4) solution for etching aluminum from the model system Ti3AlC2 MAX (M: transition metals, A: Al, X: carbon.), resulting in the formation of B-doped Ti3C2Tx MXene. Ex-Situ electrochemical X-ray diffraction (XRD) analysis showed reversible (002) plane changes in B-doped Ti3C2Tx MXene, from 5.72° to 7.0°, indicating ions intercalation and deintercalation, a first-time demonstration of significant ion transportation. Such fundamental insight determines that the specific capacitance of B-doped Ti3C2Tx MXene has found to be 396 F/g at current density of 1 A/g. This research introduces a novel synthesis approach aimed at understanding microstructural transformations of B-doped Ti3C2Tx MXene during electrochemical processes. This contributes to the advancement of MXene-based materials for future electrochemical applications.

Aesthetic synthesis and comparative study of graphitic carbon nitride for energy storage applications

ABSTRACT Graphitic carbon nitride (gCN) has emerged as a suitable 2D material for various applications, such as photocatalysis, energy storage, and conversion. Due to their abundance of active sites, their unique layered structure, metal-free characteristics, high physicochemical stability, generous in nature, being environmentally friendly and having unique electrical characteristics. In this study, we use a one-step pyrolysis procedure to address these limitations and propose robust, low-cost, and scalable ways to synthesise materials. The synthesised gCN material graphitic phase is confirmed by X-ray diffraction analysis, the layered structure of the sp2 hybridised C-N bonding features is shown by FT-IR analysis. FESEM analyses provide insights into the morphology of gCN. Elemental identification and oxidation states were investigated using X-ray photoelectron spectroscopy (XPS). The electrochemical properties of gCN are performed using a two-electrode system with PVA/KOH electrolyte. The gCN nanostructure shows a specific capacitance of 183.20 F/g at a current density (CD) of 2 A/g, an energy density (ED) of 30.44 Wh/kg, and a power density (PD) of 2739.6 W/kg. Furthermore, the gCN nanostructure shows an excellent cycle life with 87.11% capacitance retention and 98.13% coulombic efficiency. These investigations clarify the electrochemical properties of gCN as an electrode material for supercapacitors.

Nitrogen and sulfur co-doped carbonized lignin nanotubes for supercapacitor applications

Carbon electrode material is crucial for the development of electric double-layered supercapacitor in clean energy storage and rechargeable aspects. Although lignin consists the promising biomass based carbon resource for containing higher carbon atom ratio than 60 %, it is still the difficult challenge to precisely tailoring the porous structure characteristics and surface property to facilitate the electrolyte penetration and rapid ion transportation. Herein, the lignin nanotubes (LNT) were successfully synthesized in a convenient molecular self-assembly way, which were subsequently carbonized and activated, with introduction of melamine as nitrogen doping agent, into hetero-atom doped lignin carbon nanotubes (LCNT) as electrode material for supercapacitor. The resultant LCNT exhibit excellent pore structure, and high degree of graphitization. At a current density of 0.5 A/g, the as high specific capacitance as 391.4 F/g was achieved. Furthermore, under symmetric double-layered capacitor electrode systems, the as prepared N, S co-doped LCNT electrode demonstrated a specific capacitance of 28.6 F/g at a high current density of 20 A/g, which presented a practically applicable energy storage efficiency. It has convincingly demonstrate the substantial potential of LCNT as biomass derived carbon materials for electrochemical energy storage devices, positioning them as a promising and competitive candidate for electrode materials.

Ti3C2Tx/CDs@MnO2 composite as electrode materials for supercapacitors: synthesis and electrochemical performance

Ti3C2Tx/CDs@MnO2 composite as electrode materials for supercapacitors: synthesis and electrochemical performance

Coal-Derived Porous Carbon as Versatile Electrode Materials for Aqueous, Water-in-Salt, and Organic Electrolytes, and Fabrication of Pouch Cell Supercapacitor toward Power Application

Coal-Derived Porous Carbon as Versatile Electrode Materials for Aqueous, Water-in-Salt, and Organic Electrolytes, and Fabrication of Pouch Cell Supercapacitor toward Power Application

Copper/Cobalt based metal phosphide composites as positive material for supercapacitors

The excellent conductivity and fast redox kinetics of transition metal phosphides (TMPs) have made them a suitable electrode material for energy storage in the field of supercapacitors (SCs). In this paper, coral-like Cu3P/CoP heterostructures have been obtained by a simple solid-phase grinding and subsequent phosphating method. Importantly, the Cu3P/CoP heterostructure can provide sufficient charge to further accelerate the Faraday kinetics of the redox reaction due to its ability to generate an internal electric field, thus improving its electrochemical performance. Through density-functional theory (DFT) computations, it is demonstrated that the heterostructures of Cu3P/CoP enhances the metal-like conductivity of the composite, exhibiting more electron-occupied states around the Fermi energy level and improves the charge-transfer efficiency of the heterostructure. The results show that the Cu3P/CoP-1 composite with a 1:1 Cu/Co molar ratio has the best electrochemical performance. At 1 A·g−1, it exhibits an excellent specific capacitance of 804.3 F·g−1, and when the current density is increased to 10 A·g−1, it retains its capacitance for 92.8% of 10,000 cycles. Furthermore, with a power density of 806.23 W·kg−1, an asymmetric supercapacitor (ASC) built using Cu3P/CoP-1 as the cathode may produce an energy density of 37.40 Wh·kg−1. The reasonable design of heterostructures of bimetallic TMPs in this research offers a workable plan for exploring electrode materials with excellent capacitive properties.