Supercapacitor Technology Research Articles

One-pot synthesis of hydroxypropyl methylcellulose-based gel polymer electrolytes for high-performance supercapacitors

The electrolyte is a crucial component that significantly affects the electrochemical performance of supercapacitors. The hydroxypropyl methylcellulose (HPMC)-based gel polymer electrolyte (GPE) with high operating voltage was synthesized via an innovative “one-pot” method in this study, and the impacts of organic solvent/water ratio and LiNO3 concentration on gelation and conductivity of the GPE were investigated systematically. Under the optimal condition with a DMF/water ratio of 10:0 and the incorporation of 7 % LiNO3, the ionic conductivity reached 1.06 S m−1. Integrated into symmetric supercapacitors, the HPMC-based GPE demonstrated an expanded electrochemical window of 2.7 V. It also possessed a specific capacitance of 115.8 F g−1 at 1.0 A g−1, an energy density of 29.31 Wh kg−1, and outstanding cyclic stability, retaining 86 % of its initial capacitance after 2000 cycles. Through cyclic stability tests under pressure conditions, the assembled flexible supercapacitors were able to maintain capacitance retention of 60 % and coulombic efficiency of 97 %. This work offers a streamlined synthesis for HPMC-based GPE with superior electrochemical properties, which exhibits its potential in advancing supercapacitor technology for flexible electronics.

Synergistic effects of MXene and Co3O4 in composite electrodes: High-performance energy storage solutions

The development of high-performance electrode materials is crucial for advancing supercapacitor technology. The two-dimensional layered structure of MXene (Ti3C2Tx) presents high conductivity, abundant surface functional groups and accessible ion interaction between layers. However, the MXene suffers from the layer aggregation. To overcome this issue, we synthesized a composite material combining MXene with cobalt oxide (Co3O4) to enhance electrochemical performance in supercapacitors. MXene’s two-dimensional layered structure, high conductivity, and abundant surface functional groups allow for efficient ion intercalation, while Co3O4 contributes high theoretical capacitance and rich oxidation states. The resulted MXene/Co3O4 composite exhibits an impressive areal capacitance of 6.456F/cm2 at a current density of 3 mA/cm2, maintaining 90.52 % capacitance retention at 30 mA/cm2, and 81.37 % capacity after 5000 charge–discharge cycles. Additionally, the asymmetric supercapacitor (ASC) device fabricated using the MXene/Co3O4 composite achieves a power density of 6.41 mW/cm2 at an energy density of 0.37 mWh/cm2, with 82.3 % capacitance retention after 5000 cycles. These results demonstrate that the MXene/Co3O4 composite material is a promising candidate for high-performance supercapacitors, offering significant improvements in rate capability and long-term cycling stability.

Synergistic coupling of NiCo-LDH in high-performance supercapacitors via hydrothermal method: Optimal utilization of the potential window

Enhancing the efficiency of layered nickel-cobalt double hydroxides (NiCo-LDH) as electrode materials represented a promising strategy for advancing supercapacitor technology and improving energy storage systems. However, achieving optimal synthesis conditions and addressing the inherent limitations of NiCo-LDH remained critical challenges. In this study, we developed a novel hydrothermal approach to fabricate ultrathin NiCo-LDH nanosheets with a highly porous architecture. In the present study, we have introduced a hydrothermal methodology aimed at the fabrication of ultrathin NiCo-LDH nanosheets characterized by an intricate and highly porous architecture. This innovative approach entailed the simultaneous deposition of nickel and cobalt hydroxides in the presence of ammonium fluoride, a technique that not only streamlined the synthesis process, but also markedly augmented the electrochemical performance of the resultant material. These effects collectively contributed to improved electron transport and structural stability. The optimized NiCo-LDH-18 electrode achieved an exceptional specific capacitance of 2266.6 F g⁻1 and an energy density of 104.8 W h kg⁻1, with a remarkable 93.19 % capacitance retention after 40,000 cycles. Additionally, the potential window of the system closely approximated its theoretical maximum, reaching 96.88 % at a current density of 10 A g⁻1. This refined synthesis strategy offered a significant advancement in supercapacitor performance and stability. By overcoming the inherent drawbacks of traditional supercapacitors, the developed materials provided an effective solution for meeting the growing demand for storage devices with high energy density.

Ag NPs-modified NiCoMn layered double hydroxides electrodes for high-performance asymmetric supercapacitors

The development of supercapacitor technology has been hindered by limitations in achieving both high power density and long cycle stability. Layered double hydroxides (LDHs) have emerged as promising candidates to address these challenges. In this study, we synthesized three distinct electrodes: NiCoMn LDH (LDH), Ag-citrate nanoparticles (Ag NPs), and a composite of Ag-citrate/NiCoMn LDH (AgNPs/LDH), to explore their electrochemical performance. The structural and morphological characteristics of the synthesized materials were confirmed using scanning electron microscopy (SEM), X-ray diffraction (XRD), fourier transform infrared spectroscopy (FTIR), and raman spectroscopy. Among the materials, the Ag NPs/LDH composite exhibited superior electrochemical properties, with distinct anodic and cathodic peaks of higher current intensity and an expanded integrated area in the current-voltage curve. Additionally, impedance analysis revealed the lowest charge transfer resistance, indicating efficient charging and discharging processes. In addition, the Ag-NPs/NiCoMn composite exhibited a remarkable aerial-specific capacitance of 2764 mF.cm−2 at 5 mA cm−2 in a three-electrode configuration. Furthermore, in an asymmetric supercapacitor (ASC) device configuration of AgNPs/LDH as a working electrode and Activated carbon as a working electrode (shorthand form AgNPs/LDH ||AC ASC), a specific capacitance of 1850 mF.cm−2 at 5 mA.cm−2 was achieved. Encouragingly, the AgNPs/LDH||AC ASC device exhibited an energy density of 0.593 mWhcm−2 at a power density of 10 mW.cm−2, maintaining a 0.175 mWhcm−2 at a high-power density of 90 mWcm−2, while retaining 102 % of its capacitance after 4000 charging and discharging cycles. Overall, the AgNPs/LDH electrode material demonstrates significant potential for advancement in supercapacitor technology.

Improved electrochemical performance of the iron-doped NiO nanoparticles at varying calcination temperatures and examination of their supercapacitor applications

The scientific community is interested in increasing oxide electrochemical characteristics for supercapacitor applications. The present research explores the development of supercapacitor electrodes using Fe-doped NiO nanoparticles synthesised via chemical co-precipitation method with varied calcination temperatures (350, 550, and 750 °C). The key innovation of the work lies in the systematic investigation of the effects of calcination temperature on the electrochemical properties and structural characteristics of the Fe-doped NiO nanoparticles. X-ray diffraction (XRD) analysis revealed a trend of increasing crystallite size with rising temperatures, and optical studies indicated a decreasing trend in the energy band gap from 3.67 eV to 3.23 eV. Fourier transform infrared (FTIR) spectroscopy confirmed the metal-oxygen bond in the molecules. Scanning electron microscopy (SEM) and High-Resolution Transmission Electron Microscopy (HR-TEM) analysis showed the mesoporous spherical morphology of the nanoparticles. Energy-dispersive X-ray spectroscopy (EDX) ensured the samples' elemental composition purity. Brunauer–Emmett–Teller (BET) shows a specific surface area of around 180.8 m2/g was obtained for Fe-doped NiO nanoparticles at 350 °C. Electrochemical tests demonstrated that the Fe-doped NiO electrodes, especially calcined at 350 °C, exhibit superior specific capacitance values (635 F/g) and impressive cycle stability with 93.29 % capacitance retention after 5000 cycles. The present demonstrates the potential of optimizing calcination temperatures to enhance the electrochemical performance and stability of Fe-doped NiO supercapacitor electrodes, marking a significant advancement in supercapacitor technology.

MnO2‐Infused PAN Carbon Nanofibers Synthesized via Electrospinning for Enhanced Supercapacitor Performance

AbstractSupercapacitors (SCs) are crucial for high‐performance energy storage, offering high power density, swift charge–discharge rates, and durability. The enhancement of their performance hinges on the development of advanced electrode materials. This study presents an innovative method involving polyacrylonitrile (PAN) nanofibers adorned with manganese dioxide (MnO₂) nanoparticles (NPs), created through electrospinning and subsequent thermal treatment. This synergy exploits the extensive surface area and electrical conductivity of PAN nanofibers along with the substantial capacitance of MnO₂. The MnO₂‐coated PAN nanofibers reached an impressive specific capacitance of 247 F g−1 at a scan rate of 10 mVs−1, markedly boosting the efficacy of all‐solid‐state asymmetric SCs. The SCs, incorporating a polyvinyl alcohol (PVA)/potassium hydroxide (KOH) gel electrolyte, exhibited an energy density of 8.2 Wh kg−1 at a power density of 700 W kg−1, preserving 80.4% of their original capacitance after 5000 cycles. This research is pioneering in combining MnO₂ with PAN nanofibers, marking a significant leap forward in supercapacitor technology with enhanced energy storage capacity and prolonged stability. These findings underscore the promise of these composite materials in future energy storage solutions.

Carbonized porous zeolitic imidazolate framework as promising electrode for electrochemical supercapacitors

In order to manufacture effective supercapacitors with improved electrochemical performance, it is imperative to investigate greater surface area electrode materials. This work describes the development of a cost-effective method for the carbonization of porous zeolitic imidazole framework (ZIF8) to utilize as electrode of electrochemical supercapacitors. The electrode materials were prepared by synthesizing highly porous ZIF8-P followed by pyrolysis at 500 °C (ZIF8-P-500). The pyrolysis of ZIF-8 significantly strengthened the porous behavior by maintaining their hexagonal particles and obtaining high surface to volume ratio. The measurements using constant current charge/discharge (GCD) and cyclic voltammetry (CV) were used to evaluate the electrochemical capacitance characteristics of the synthesized ZIF8-P based electrode. The supercapacitor assembly using the optimized ZIF8-P electrode exhibited a high specific capacitance of ∼423.9 Fg–1 with exceptional cycle stability by maintaining capacitance of ∼86.7 % from its initial capacitance after 5000 cycles. Thus, the results indicate that the ZIF8-P based supercapacitor offers a compelling path for creating porous carbon electrodes from MOFs using low cost pyrolysis for advancing supercapacitor technology.

Opportunities and Threats for Supercapacitor Technology Based on Biochar—A Review

This review analyzes in detail the topic of supercapacitors based on biochar technologies, including their advantages, disadvantages, and development potential. The main topic is the formation of precursors in the process of pyrolysis and activation, and the possibility of the application of biochar itself in various fields is brought closer. The structure, division, and principle of operation of supercondensates are discussed, where their good and bad sides are pointed out. The current state of the scientific and legal knowledge on the topic of biocarbon and its applications is verified, and the results of many authors are compared to examine the current level of the research on supercapacitors based on biochar electrodes created from lignocellulosic biomass. Current application sites for supercapacitors in transportation, electronics, and power generation (conventional and unconventional) are also examined, as is the potential for further development of the technology under discussion.

Wet-chemical synthesized TiN-CuO nanocomposite: Advancing supercapacitor technology with high energy and power density

Modern-era energy crises have arisen as a result of industry's quick expansion. There must be a proliferation of autonomous, renewable-energy-powered, high-capacity storage systems. The high specific capacitance (Cs) is a result of the Electric Double Layered Capacitors (EDLC's) stellar cathode characteristics. The remarkable conductivity and storage capacity of transition metal nitride-based oxides (TMOs) have made them an attractive option for use as cathode materials in SC devices. The present study successfully synthesized the TiN-CuO composite for electrode material by employing the straightforward wet-chemical method. But the fact that the TiN-CuO combination is crystalline suggests it could be used as an electrode in SCs. The electrochemical performance of the TiN-CuO electrode was also highlighted by its excellent Cs of 843.5 F g−1. Furthermore, the TiN-CuO‖MnO2-KOH electrode displays a power density (Pd) of 17595 W/kg and an energy density (Ed) of 44.88 Wh kg−1. In addition, the TiN-CuO‖MnO2-KOH electrode has shown remarkable cyclic stability of 97.3 % up to 10,000 cycles, at 10 A g−1. The electrochemical characteristics of fabricated TiN-CuO electrode material are superior to those of pure materials, rendering it an attractive candidate for use in energy storage devices such as SCs.

Flexible zinc-ion hybrid supercapacitor based on Co2+-doped polyaniline/V2O5 electrode

With the rapid advancement of renewable energy sources and portable electronic devices, the demand for high-performance energy storage systems is growing, driving continuous progress in supercapacitor technology. Zinc-ion hybrid supercapacitors (ZIHS), known for their higher safety, cost-effectiveness, and environmental friendliness, have become a hot research topic. Vanadium pentoxide (V2O5) possesses flexible multivalence, low cost, low toxicity, wide voltage window, high capacitance, and high energy density. However, its poor electrical conductivity and low cycling stability hinder its electrochemical performance, thus limiting its application in ZIHS. Here, we propose a novel strategy of incorporating Co2+ ions and conductive polyaniline (PANI) with V2O5 (CoVO-PANI) as cathode materials for ZIHS. The synergistic effect between cobalt ions and polyaniline have led to an expansion of the interlayer spacing in CoVO-PANI, which reduce the binding energy of Zn2+ ion insertion, decrease the diffusion barrier of Zn2+ ion insertion, and enhanced the electronic conductivity of the material for electron transport. In result, the CoVO-PANI@CC//2 M ZnSO4//AC@CC can reach the areal capacitance of 847.3 mF cm−2 at 1 mA cm−2. Following 2000 times at 50 mA cm−2, the CoVO-PANI@CC//2 M ZnSO4//AC@CC maintains a retention rate of 81.37 %, and can achieve a Coulombic efficiency of 100 %. The assembled flexible ZIHS device exhibits excellent flexibility and stability, with an areal capacitance of 775.6 mF cm−2 at 1 mA cm−2. This work demonstrates the tremendous potential of CoVO-PANI@CC as a cathode material for ZIHS.

SrCoO3-based perovskites with enhanced electrochemical performance through structural tailoring induced by B-site substitution

The progression of supercapacitor technology hinges on the discovery of high-performance electrode materials to enhance energy storage. SrCoO3-δ perovskite holds considerable promise potential as an anion intercalation electrode material. To elucidate the structural and electrochemical performance modulation rules of SrCoO3-based perovskites, this study synthesized SrCo0.875M0.125O3-δ (M = Ti, Ta, Nb, Fe) perovskites with different B-site ion substitutions. The structural tailoring induced by B-site substitution were thoroughly investigated alongside their corresponding electrochemical performance. Notably, SrCo0.875Ti0.125O3-δ exhibited a simple cubic structure, while the other samples displayed a tetragonal structure. Additionally, SrCo0.875Fe0.125O3-δ displayed numerous oxygen vacancies and significant distortion in the [CoO6] octahedron, which is attributed to the lower valence state of Fe. At a current density of 1 A g−1, the specific capacities of SrCo0.875M0.125O3-δ (M = Nb, Ti, Fe, Ta) perovskites were 984.43, 853.33, 503.53, and 452.00C/g, respectively. SrCo0.875Nb0.125O3-δ demonstrated the highest specific capacity and capacity retention rate across various current density, owing to its relatively stable structure with appropriate oxygen vacancies and multivalent state changes of Nb. In contrast, SrCo0.875Fe0.125O3-δ, with excessive oxygen vacancies and severe structural distortions, exhibited restricted electrochemical performance, particularly at higher current densities. Integrating structural and performance analysis, this work proposes an optimization strategy for the electrochemical performance of SrCoO3-δ-based perovskite electrode materials, emphasizing the importance of tailoring multivalent B-site elements to achieve a stable perovskite structure with appropriate oxygen vacancies.

Mechanical Processing with Solid-State of Supercapacitor Materials: A Review of High Energy Milling and High Velocity Particle Methods

Supercapacitors have emerged as a crucial energy storage technology, bridging the gap between traditional capacitors and batteries. The performance of supercapacitors is heavily dependent on the properties of the electrode materials used. Mechanical processing methods, particularly High Energy Milling (HEM) and High-Velocity Particle (HVP) methods have shown great promise in enhancing the physical and electrochemical properties of supercapacitor materials. This review explores the fundamental principles, mechanisms, and recent advancements in HEM and HVP techniques for the synthesis and modification of supercapacitor materials. High energy milling, including ballmill and attritor milling, facilitates particle size reduction, increased surface area, and the creation of nanostructures, leading to improved capacitance and energy density. High velocity particle methods, such as cold spraying and thermal spraying, enable the deposition of uniform and dense coatings, enhancing conductivity and stability. The review also discusses the impact of process parameters on material properties, the challenges faced in scaling up these techniques, and the potential future directions for research. By providing a comprehensive overview of these mechanical processing methods, this paper aims to highlight their significance and potential in advancing supercapacitor technology.

Enhanced electrochemical performance with exceptional capacitive retention in Ce–Co MOFs/Ti3C2Tx nanocomposite for advanced supercapacitor applications

This study introduces a high-performance Ce–Co MOFs/Ti3C2Tx nanocomposite, synthesized via hydrothermal methods, designed to advance supercapacitor technology. The integration of Ce–Co metal-organic frameworks (MOFs) with Ti3C2Tx (Mxene) yields a composite that exhibits superior electrochemical properties. Structural analyses, including X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM), confirm the successful formation of the composite, featuring well-defined rod-like Ce–Co MOFs and layered Ti3C2Tx sheets.Electrochemical evaluation highlights the exceptional performance of the Ce–Co MOFs/Ti3C2Tx nanocomposite, achieving a specific capacitance of 483.3 Fg⁻1 at 10 mVs⁻1, a notable enhancement over the 200 Fg⁻1 of Ce–Co MOFs. It also delivers a high energy density of 78.48 Whkg⁻1 compared to 19 Whkg⁻1 for Ce–Co MOFs. Remarkably, the nanocomposite shows outstanding cyclic stability with a capacitance retention of 109 % after 4000 cycles and electrochemical surface area (ECSA) of 845 cm2, coupled with a reduced charge transfer resistance (Rct) of 2.601 Ω and an equivalent series resistance (ESR) of 0.8 Ω. These findings demonstrate that the Ce–Co MOFs/Ti3C2Tx nanocomposite is a groundbreaking material, offering enhanced energy storage, conductivity, and durability, positioning it as a leading candidate for next-generation supercapacitors.

Nanocomposites combining 2D WS2 and 1D polyaniline for enhanced high-performance supercapacitors

The field of flexible energy storage is increasingly focusing on conductive polymers due to their inherent flexibility, high theoretical capacitance, and suitability for thin-film applications. Polyaniline stands out for its excellent capacitance and electrochemical reversibility. However, its limited cyclic stability has hindered its use in supercapacitors. To Address this, our study focuses on development of a hybrid nanocomposite that merges two-dimensional tungsten disulfide with polyaniline (WS2/PANI), that created through in-situ oxidative polymerization. Serving as an electrode material, it showcased considerable surface area and structural integrity, thanks to the electrostatic interactions and hydrogen bonds between WS2 and PANI. The nanocomposite achieved a specific capacitance of 464 Fg−1 at a current density of 10 mVs−1, displaying outstanding stability and rate capability. Moreover, we have developed all-solid-state asymmetric supercapacitors using WS2/PANI/C, activated carbon (AC/C) and Na2SO4-saturated filter paper as the positive, negative electrodes and electrolyte, respectively. The constructed device exhibited an energy density of 12.9 Whkg−1, power density of 395 Wkg−1 and retained 67 % of its initial capacitance even after 10,000 cycles. The impressive electrochemical performance of this device braces the promising future for hybrid supercapacitor technology.

Synthesis and characterization of Pd-doped perovskite/Vulcan XC-72 carbon nanocomposite for sustainable supercapacitor technology

Due to the lower equivalent series resistance compared to other types of energy storage devices, supercapacitor electrodes can therefore be an ideal choice for energy storage. In this study, a perovskite-based metallic compound, La0.6Sr0.4Fe0.9Pd0.1O3 was synthesized by the sol-gel method and combined with carbon Vulcan XC-72 to create an effective nanocomposite-based modifier for the development of mini supercapacitor. Morphological studies of the obtained compounds were carried out using a variety of characterization techniques including X-ray Diffraction (XRD), Energy Dispersive X-ray Spectroscopy (EDX), Fourier-transform infrared spectroscopy (FT-IR), and Field Emission Scanning Electron Microscope (FE-SEM) and X-ray Photoelectron Spectroscopy analysis (XPS). On the other hand, the electrochemical feasibility of the synthesized nanocomposite and the developed La0.6Sr0.4Fe0.9Pd0.1O3/Vulcan XC-72 -based supercapacitor was demonstrated by applying various approaches including cyclic voltammetry (CV), galvanostatic charge/discharge (GCD), and electrochemical impedance spectroscopy (EIS). The La0.6Sr0.4Fe0.9Pd0.1O3/Vulcan XC-72 shows the highest specific capacitance (329 F/g) with a power density of 750 W/kg and an energy density of 4.8 Wh/kg at a current density of 0.01 mA/g. In order to evaluate the stability of the designed supercapacitor, long charge/discharge cycles were also carried out. After 5000 charge/discharge cycles, the specific capacity reached about 76.47% of its original value. The present results show that the La0.6Sr0.4Fe0.9Pd0.1O3/Vulcan XC-72 nanocomposite can be efficiently used as a potential material for energy storage, which may be promising for the future.

Review of supercapacitor technology and applications

While the world population is increasing day by day, environmental problems are reaching a level that cannot be ignored. Environmentalist steps are being taken in many areas, and governments are resorting to sanctions. It aims to reduce fossil fuel use as an environmental step in the transportation industry. Increasing the use of electric vehicles will be significant progress in achieving this goal. Batteries are generally used to store energy in electric vehicles. However, besides the weight problem and insufficient power density of the batteries, they have disadvantages, such as being produced from environmentally harmful materials. In this context, new energy storage technologies are being researched. One of them is “supercapacitor” technology. This paper is a review article examining several aspects of supercapacitors.

Synthesis and electrochemical performance of low cost nitrogen-doped carbon cryogel composites as supercapacitor electrodes

Developing cost-effective methods for synthesizing Nitrogen-doped carbon cryogels is crucial for advancing supercapacitor technology due to their enhanced electrochemical properties. Nitrogen-doped porous carbon cryogels are synthesized through the freeze-drying method by substituting resorcinol with phenol and using urea/melamine as nitrogen sources. The effect of nitrogen sources on the structure and electrochemical performance is investigated. In the case of carbon cryogel composites samples, using melamine as the nitrogen source (PMF) is more favorable than using urea (PUF), while both nitrogen-doped samples significantly outperform the undoped samples (PF). The PMF sample displays a specific surface area of 1119.00 m2 g−1, and a nitrogen content of 2.19 wt%. In the three-electrode system, the specific capacitance of the PMF sample reaches up to 247.9 F g−1 at a current density of 0.5 A g−1, and its rate performance is 85.52 %. By comparison, the PF sample exhibits specific capacitance and rate performance of 85.4 F g−1 and 33.44 % under the same parameters. The assembled symmetric supercapacitor in a buckle type system also demonstrates exceptional energy density (14.41 Wh kg−1), long-term cycle stability, and a favorable capacitance retention rate (72.2 %). These excellent electrochemical performances can be attributed to the synergistic effects of the hierarchical pore structures and heteroatoms doping.

Strategic Fabrication of Au4Cu2 NC/ZIF‐8 Composite Via In Situ Integration Technique for Enhanced Energy Storage Applications

AbstractMetal–organic frameworks (MOFs), known for their extensive porosity and versatile crystallinity, play a crucial role in the development of advanced energy storage materials. However, their application is limited by stability and conductivity issues. This study addresses these challenges by integrating ultrasmall metal nanoclusters, specifically Au4Cu2 NC, synthesized using a mixed ligand strategy combining 2, 4‐Dimethyl benzene thiol (2,4‐DMBTH) and 1,2‐bis(diphenylphosphino)ethane (dppe). The bimetallic Au4Cu2 NC, characterized by Single Crystal X‐Ray Diffraction (SCXRD), is applied to zeolitic imidazolate framework‐8 (ZIF‐8) using both in situ and ex situ methods to explore their electrochemical and physicochemical properties in energy storage. The in situ Au4Cu2 NC/ZIF‐8 composite demonstrated a specific capacitance that is almost two times higher than its ex situ counterpart, attributed to homogeneous dispersion and hence enhanced conductivity. This in situ integration of atomically precise bimetallic nanoclusters on MOFs significantly boosts supercapacitor performance, offering a more effective and reliable solution for energy storage. Further, in practical applications, this device demonstrated an energy density of 87.2 Wh kg−1 at a power density of 1474 W kg−1, highlighting its robustness and potential for high‐performance energy storage applications. This approach effectively combats the issue of nanocluster aggregation on substrates, marking a significant progression in supercapacitor technology.

Computational investigation of quantum capacitance enhancement in Mg-substituted MgB[formula omitted]-based supercapacitor electrodes

The investigation into surface functionalization’s effect on magnesium diboride (MgB2) presents a captivating research direction, shedding light on the modifications in its electronic structure resulting from functionalization systematically analysed through density functional theory (DFT) calculations. This study systematically investigates the effects of varying functionalization concentrations on MgB2, unveiling a profound influence on its quantum capacitance(CQ). Maximum enhancement is found within an optimal doping range; however, impurity ad-atom interactions may cause quantum capacitance to decrease above this barrier. Notably, these ad-atoms act as magnetic impurities, generating a localized density of states near the Fermi energy, thereby increasing charge carrier density and resulting in a remarkable increase in quantum capacitance. We also emphasize the importance of functionalized MgB2 as an example of a two-dimensional supercapacitor electrode material in the advancement of energy storage technology. These materials promise improved charge storage capacities and tailored electronic properties, which will accelerate the development of effective energy storage technologies. This paper highlights the potential direction of two-dimensional electrode materials in developing supercapacitor technology towards superior energy storage systems by elucidating fundamental mechanisms using quantum capacitance enhancement.

Waste-to-energy material: Winery-waste derived heteroatoms containing graphene-like porous carbon for high-voltage supercapacitor

Recycling industrial waste to produce energy and storage materials provides the best means of addressing its environmental impact and achieving economic benefits. This study used solid industrial winery waste to prepare an innovative heteroatom containing graphene-like porous carbon (HGPC) by simple heat treatment and chemical activation using KOH. The prepared N and S containing HGPC had a thin sheet-like structure, a high specific surface area (925.00 m2/g), and a micro-meso-porosity suitable for sustainable energy storage applications. A density functional theory investigation indicated that the synergistic effects of N and S co-doping enhanced both conductivity and electrolyte ion (Na+) diffusion kinetics in HGPC samples. When the solid winery waste-derived HGPC was used in a supercapacitor (SC) cell assembly with a diglyme-based electrolyte, it delivered an operating voltage window of 2.0 V, which was about twice as wide as those reported for symmetric SCs and compared well with those of asymmetric/hybrid SCs. In addition, it had a specific capacitance of 32 F/g (at the cell level) with a high energy density of 17.7 Wh/kg at a power density of 303.42 W/kg and excellent cycling stability over 10,000 charge/discharge cycles. This work shows that the solid winery waste-derived HGPC can be utilized for future SCs technology by replacing costly commercial YP-50F carbon to provide enhanced energy storage in a sustainable, green manner.