Sürdürülebilir Kalkınma Amaçları

  • ArticleYalnız künye2026
    2D/2D Borophene/Ti2NbC2Tx MXene hybrids as advanced electrodes for supercapacitors

    Yesilbag, Yasar Ozkan; Tuzluca Yesilbag, Fatma Nur; Huseyin, Ahmad; Salih, Ahmed Jalal Salih; Ertugrul, Mehmet

    Two-dimensional (2D) hybrid electrodes combining complementary charge-storage mechanisms represent a promising approach for advanced supercapacitors. In this work, few-layer β-borophene nanosheets were synthesised via a modified Hummers' method and integrated with Ti2NbC2Tx MXene to form 2D/2D hybrid electrodes. Structural characterization confirmed successful borophene exfoliation, MXene–borophene heterostructure formation with locally ordered domains and enhanced ion accessibility. Electrochemical measurements demonstrated that hybrid electrodes significantly outperformed pristine MXene and borophene. The MX-B10 composition exhibited the highest specific capacitance, superior rate capability, and optimal charge-transfer kinetics attributed to synergistic surface-controlled capacitance from borophene and diffusion-assisted ion transport in MXene. A symmetric solid-state supercapacitor (SSSC) assembled with MX-B10 electrodes achieved 54 Wh kg−1 at ~300 W kg−1, retaining 23.2 Wh kg−1 at ~7.6 kW kg−1 with ~97% capacitance retention after extended cycling, These results highlight the potential of borophene–MXene heterostructures for high-performance energy storage applications.

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  • Book ChapterYalnız künye2025
    2D Materials for Solar-Assisted Hybrid Energy Storage Devices: Photo-Supercapacitors

    Yesilbag, Yasar Ozkan; Yesilbag, Fatma Nur Tuzluca; Huseyin, Ahmad; Salih, Ahmed Jalal Salih; Ertugrul, Mehmet

    Photo-supercapacitors (PSCs) are gaining recognition as a feasible option for future electronic devices and have attracted considerable research attention in recent years. These devices, designed for storing light energy, are viewed as a promising energy source for smart electronics, flexible technologies, and wearable devices. PSCs integrate solar cells with supercapacitors, facilitating the conversion of light energy into electrical energy, which is subsequently stored in chemical energy. Their exceptional light conversion efficiency and outstanding energy storage capabilities distinguish PSCs as key players in light-operated energy storage solutions. Recent studies have extensively explored the application of nanomaterials (1D, 2D, and 3D) as potential electrode materials in these devices. Furthermore, there has been a notable shift toward research to decrease dependence on traditional energy sources. This chapter delves into PSCs’ structure, mechanisms, and operational principles alongside an overview of the available types. It concludes with significant recommendations for improving PSC performance by innovating new materials that exhibit optical and capacitive properties. Additionally, it addresses PSC’s challenges and issues and proposes appropriate solutions.

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  • ArticleYalnız künye2025
    Electrochemical performance of Fe2Al1-xB2 MBene as a novel electrode material for supercapacitor applications

    Tuzluca Yesilbag, Fatma Nur; Yesilbag, Yasar Ozkan; Huseyin, Ahmad; Salih, Ahmed Jalal Salih; Ertugrul, Mehmet

    The growing global demand for efficient and sustainable energy storage systems has intensified the need for advanced electrode materials with superior performance and stability. This study focuses on the synthesis and characterization of Fe2AlB2 MAB phase and Fe2Al1-xB2 MBene, highlighting their potential for energy storage applications. The Fe2AlB2 MAB phase was synthesized using FeB and Al powders via high-temperature sintering (1200 °C for 2 h), followed by selective etching of aluminum layers with a 2 M HCl solution to produce Fe2Al1-xB2 MBene. Electrochemical measurements demonstrated that Fe2Al1-xB2 MBene exhibits excellent pseudocapacitive behavior, achieving a specific capacitance of 276 F g−1 at 0.5 A g−1 in a three-electrode system. An asymmetric supercapacitor (ASC) configuration achieved an energy density of 20.6 Wh kg−1 at a power density of 306.4 W kg−1, with 96 % capacitance retention after 10,000 cycles. This research represents one of the pioneering studies on Fe2Al1-xB2 MBene, emphasizing its potential as a high-performance electrode material for next-generation energy storage devices. The findings provide valuable insights into the design and application of 2D MBenes for energy-related technologies.

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  • Review ArticleAçık Erişim2025
    Nitrogen-doped MXene for supercapacitor: A review

    Salih, Ahmed Jalal Salih; Huseyin, Ahmad

    Efforts to enhance the properties of MXene have been ongoing since its discovery in 2011. Various strategies have been explored to improve its performance for many applications. One such strategy is doping MXene with heteroatoms. Doping has been studied for several applications, including supercapacitors, with particular attention given to nitrogen doping. This review focuses on doping MXene with nitrogen for supercapacitor applications. It discusses the effects of doping on the chemical, physical, and structural properties of MXene, the doping mechanisms (lattice substitution, functional substitution, and surface adsorption), and the contributions of each mechanism to the enhancement of electrochemical performance. Additionally, the review discusses doping methods and their impact on the performance of MXene as supercapacitor electrodes. It presents results from experimental studies and discusses several of these findings. Finally, it provides recommendations to guide future research and optimize outcomes in this field.

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  • Review ArticleYalnız künye2025
    Batteries and supercapacitors: An analytical perspective on electrode materials and performance challenges

    Huseyin, Ahmad; Salih, Ahmed Jalal Salih

    Energy storage devices, especially batteries and supercapacitors, are essential components in portable electronics and electric vehicles, and their role in supporting renewable energy systems is becoming increasingly critical. This review investigates their principles, types, and performance challenges, with a particular focus on energy density, power density, charge/discharge rates, and cycle life. While lithium-ion batteries are widely used for their high energy density, they face significant challenges such as long charging times, high costs, and safety concerns. Consequently, alternative battery technologies, including lithium-sulfur, lithium-air, sodium-ion, and zinc-based systems, are under active investigation. Supercapacitors, known for their rapid charge/discharge cycles and high power density, are limited by their low energy density. A key area of ongoing research is the optimization of electrode materials, such as carbon-based compounds, metal oxides, and conductive polymers, to enhance the performance of both batteries and supercapacitors. This work discusses the mechanisms of energy storage, electrode degradation, and electrolyte stability, while offering insights into future developments. It underscores the importance of distinguishing between the performance characteristics of batteries and supercapacitors to avoid misconceptions, as each technology operates on distinct principles that affect their efficiency and applications.

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  • ArticleYalnız künye2025
    Ti2NbC2Tx MXene Nanosheets as an Ordered Double Transition Metal Electrode for High-Performance Supercapacitors

    Tuzluca Yesilbag, Fatma Nur; Yesilbag, Yasar Ozkan; Huseyin, Ahmad; Salih, Ahmed Jalal Salih; Ertugrul, Mehmet

    The increasing demand for advanced materials in energy storage underscores the importance of chemical diversity in nanomaterials. Ordered double transition metal (DTM) MXenes have emerged as promising atomically layered 2D materials. This study investigates the flexible Ti2NbC2Tx MXene, synthesized from the ordered Ti2NbAlC2 MAX phase, as a supercapacitor electrode material. Electrochemical analyses revealed specific capacitances of 322 and 642 F g-1 at a current density of 0.5 A g-1 in Na2SO4 (Na) and H2SO4 (H) electrolytes, respectively. Ti2NbC2Tx MXene exhibited exceptional cycling stability, retaining 95% capacitance in Na2SO4 and 100% in H2SO4 after 10,000 charge/discharge cycles. Furthermore, an asymmetric supercapacitor (ASC) was fabricated using Ti2NbC2Tx MXene as the positive electrode and overcapacitive activated carbon as the negative electrode with PVA-Na and PVA-H gel electrolytes. The ASC achieved energy densities of 31.1 and 34.0 W h kg-1 for PVA-Na and PVA-H electrolytes, respectively. These results highlight the potential of Ti2NbC2Tx MXene, with its unique ordered structure and double transition metal composition, for foundational research and applications in advanced energy storage technologies.

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  • ArticleAçık Erişim2024
    Synthesis of Tungsten Disulfide on B-N-Doped Carbon Nanotubes to Enhance the Electrochemical Performance of Supercapacitors

    Yeşilbağ, Yaşar Özkan; Yesilbag, Fatma Nur Tuzluca; Huseyin, Ahmad; Salih, Ahmed Jalal Salih

    In this research, boron and nitrogen-doped carbon nanotubes (B-N-CNTs) were synthesized at 900°C using the FCCVD method. Carbon, nitrogen, and boron as source materials were simultaneously introduced using a batch- mode droplet reactor and ferrocene as a catalyst. B-N-CNTs were obtained with diameters ranging from 10 - 50 nm and lengths around 30 – 80 μm. These B-N-CNTs were thoroughly characterized and structurally analyzed. Subsequently, tungsten disulfide (WS2) nanosheets on B-N-CNTs were synthesized using the hydrothermal method to design a composite material and were investigated as electrodes for supercapacitors. The morphological properties of B-N-CNT@WS2 were determined by various analytical techniques such as XRD, FESEM, XPS, and EDS. B-N-CNT@WS2 was investigated as an electrode for supercapacitors in two- and three-electrode cells. In the three-electrode cell, B-N-CNT@WS2 exhibited a specific capacitance of 320 F g−1 at a current density of 0.5 A g−1, while the two-electrode cell showed a capacitance of 41 F g−1. The symmetric supercapacitor at a current density of 5 A g−1 exhibited excellent structural stability by preserving 90% of its specific capacitance after 9000 cycles in the 1 V potential range.

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  • ArticleAçık Erişim2024
    The effect of Aluminum (Al) ratio on the synthesis of the laminated Mn2AlB2 MAB Phase

    Yeşilbağ, Yaşar Özkan; Yesilbag, Fatma Nur Tuzluca; Huseyin, Ahmad; Salih, Ahmed Jalal Salih

    MAB phases have recently garnered significant interest due to their excellent properties, such as high thermal and electrical conductivity, oxidation resistance, and exceptional corrosion resistance. Although the Mn2AlB2 phase has been synthesized using multiple methods recently, it requires long experimental durations (up to 7 days), high costs, and extensive experimental efforts to achieve high purity. In our study, the Mn2AlB2 MAB phase was synthesized using Al, B, and Mn as precursor materials. Specifically, we investigated the effect of Al ratios (Al:1.3, Al:3, and Al:10) on the formation of the Mn2AlB2 MAB phase. The precursor powders were mixed homogeneously in stoichiometric ratios using ball milling and cold-pressed in a 1-inch die set to form green pellets, which were then sintered in a high-temperature vacuum furnace at 1200°C. The resulting Mn2AlB2 MAB phase were characterized in terms of crystal structure, impurity, and microstructure using XRD, FESEM, and EDS.

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  • ArticleYalnız künye2024
    Designing CuO@MnCo2O4 nanowire arrays electrode on copper foam and foil substrates via chemical synthesis methods for asymmetric supercapacitor

    Tuzluca Yesilbag, Fatma Nur; Huseyin, Ahmad

    In this study, CuO nanowires were grown on copper foam (Cufoam) and copper foil (Cufoil) substrate with a cost-effective anodization method as core, and then MnCo2O4 nanowires were grown by hydrothermal synthesis method and three-dimensional (3D) core-shell nanowire arrays (NWAs) were obtained. The synthesized CuO NWAs, which provide a high surface area, contribute to the capacitance with the faradaic redox reaction and act as a current collector for the MnCo2O4 NWAs. Therefore, the 3D electrode design can increase the redox reaction, shorten the ions diffusion pathway, and exhibit low intrinsic resistance. The areal capacitance values of Cufoil/CuO, Cufoam/CuO, and Cufoam/CuO@MnCo2O4 electrodes were obtained at a current density of 0.5 mA cm−2 as 0.21, 1.02, and 2.82 F cm−2, respectively. The Cufoam/CuO@MnCo2O4 NWAs electrode exhibits excellent cycling stability of 97.3 % retention after 5000 cycles. In addition, an asymmetric supercapacitor (ASC) device was assembled by using the Cufoam/CuO@MnCo2O4 electrode and active carbon (AC) as the positive and negative electrodes, respectively. The ASC device operates in a potential range of 0–1.5 V and an energy density of up to 7.1 × 10−2 mWh cm−2 at a power density of 1.56 mW cm−2. This work may contribute to developing low-cost materials for energy storage devices.

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  • ArticleYalnız künye2023
    Rational design of MXene/Boron Carbon Nitride nanotube composite electrode for supercapacitors with improved electrochemical properties

    Tuzluca Yesilbag, Fatma Nur; Yesilbag, Yasar Ozkan; Huseyin, Ahmad; Salih, Ahmed Jalal Salih; Ertugrul, Mehmet

    3D structures obtained using 1D and 2D materials are promising materials in energy storage. Optimizing the interlayer spacing of 2D MXene through flexible conductive materials is an important step in synthesizing 3D composite electrodes. In this study, flexible and conductive MXene/BCN nanotube composite film electrodes were prepared by vacuum filtration using BCN nanotubes in different weight ratios (10 %, 20 %, and 30 %) in mixed and sandwiched structures. The mixed MXene/BCN10 (m-MX/BCN10) composite film electrode structure attained a specific capacitance of 678 F g−1, the highest of all tested electrodes, and exhibited remarkable cycle stability by retaining 95 % of its capacitance even after 10,000 charge/discharge cycles. In the symmetric supercapacitor (SSC), the cell exhibited a specific capacitance of 97 % after 10,000 charge/discharge cycles. Moreover, SSC showed an energy density of 32 Wh kg−1 and a power density of 11.5 kW kg−1. The composite electrodes made of 2D Ti3C2Tx MXene and 1D BCN nanotube materials open up a new avenue for synthesizing promising materials for energy storage in transition metal carbides and 1D nanotubes or nanowires.

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  • ArticleAçık Erişim2022
    Large-area synthesis of vertically aligned carbon nanotubes growth on the aluminum foil via FCCVD method

    Yeşilbağ, Yaşar Özkan; Yesilbag, Fatma Nur Tuzluca; Huseyin, Ahmad; Salih, Ahmed Jalal Salih; Demirez, Eda Nur

    In this study, VA-CNTs were synthesized homogeneously on Al foil at 610 oC temperature by Floating Catalyst Chemical Vapor Deposition (FCCVD) method in a horizontal tube furnace. While ethanol was used as the carbon source, ferrocene was used as the catalyst. VA-CNTs with diameters in the range of ~10-15 nm and lengths in the range of ~30-35 µm were obtained. Structural and morphological analyzes of VA-CNTs were determined using X-Ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM), Energy Dispersion X-Ray Spectroscopy (EDS), Raman Spectroscopy and X-Ray Photoelectron Spectroscopy (XPS). These VA-CNTs, synthesized by the FCCVD method on an Al foil in a large area, have the potential applications to be used especially in energy storage, optoelectronic, and sensor.

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  • ArticleYalnız künye2022
    The hierarchical synthesis of tungsten disulfide coated vertically aligned boron carbon nitride nanotubes composite electrodes for supercapacitors

    Yesilbag, Yasar Ozkan; Tuzluca Yesilbag, Fatma Nur; Huseyin, Ahmad; Ertugrul, Mehmet

    This study investigated the specific capacitance, energy density and cyclic stability parameters of a WS2 coated vertically aligned BCN nanotubes (VA-BCN-NTs) composite electrode structure. The specific capacitance of VA-BCN-NTs was found to be 364 F g−1 at a current density of 0.5 A g−1. This electrode had 97% of their initial specific capacitance after 10,000 cycles at a current density of 20 A g−1, exhibiting excellent cyclic stability. In the three-electrode cell, the specific capacitance of the VA-BCN-NT@WS2 electrode at a current density of 0.5 A g−1 was calculated to be 690 F g−1. After 5000 cycles at a current density of 20 A g−1, the electrode structure had a capacitance value of 74%, showing good stability. In the two-electrode cell, the specific capacitance of the VA-BCN-NT@WS2 symmetrical supercapacitor at a current density of 1 A g−1 was found to be 170 F g−1. It was observed to have retained 85% of its capacitance after 10,000 cycles over a 1 V potential range. While the energy density of this structure was 23.6 Wh kg−1, the power density was 4250 W kg−1.

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  • ArticleYalnız künye2022
    MnO2 nanosheets synthesized on nitrogen-doped vertically aligned carbon nanotubes as a supercapacitor electrode material

    Yesilbag, Yasar Ozkan; Tuzluca Yesilbag, Fatma Nur; Huseyin, Ahmad; Salih, Ahmed Jalal Salih; Ertugrul, Mehmet

    In the present study, nitrogen-doped vertically aligned carbon nanotubes (N-VACNTs) were synthesized on carbon cloth (CC) using the floating catalyst chemical vapor deposition (FCCVD) method, and MnO2 nanosheets were grown on them using the hydrothermal method to produce an N-VACNT@MnO2 nanocomposite structure. In this structure, a synergistic effect was obtained by combining N-VACNTs, which allow high electrical conductivity and fast ion transfer. In the galvanostatic charge-discharge (GCD) measurements performed separately in a three-electrode test cell using 1 M of Na2SO4 electrolyte, the specific capacitance of the N-VACNTs was found to be 53.7 F g−1 at a current density of 0.5 A g−1, and the specific capacitance of the N-VACNT@MnO2 electrode structure was found to be 497 F g−1. In addition, after 10,000 charge-discharge cycles at a current density of 10 A g−1, the N-VACNT electrode retained 99 % of its initial specific capacitance, while the N-VACNT@MnO2 electrode exhibited outstanding cyclic stability with 76 % of its initial specific capacitance. Moreover, in the as-fabricated asymmetric supercapacitor (ASC) using N-VACNTs and N-VACNTs@MnO2, the negative and positive electrodes achieved a stable voltage window of 0–1.7 V, with a specific capacitance of 59.4 F g−1 at a current density of 1 A g−1. Additionally, this ASC showed good cycling stability retaining 84 % of its specific capacitance at the end of 10,000 cycles. Therefore, this ASC structure with an energy density of 24.7 Wh kg−1 and a power density of 15.7 kW kg−1 are promising electrode materials for energy storage.

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  • ArticleYalnız künye2021
    Synthesis and characterization of graphene/carbon nanotube hybrid: effects of Ni catalyst thickness and H2 flow rate on growth and morphological structure

    Yesilbag, Yasar Ozkan; Tuzluca Yesilbag, Fatma Nur; Huseyin, Ahmad; Tuzluca, Metin; Ismail, Ismayadi; Ertugrul, Mehmet

    We reported a combination of the unique properties of (2D) graphene and (1D) carbon nanotubes (CNTs) by synthesizing a novel graphene/CNTs hybrid structure. Graphene and CNTs were synthesized by a two-step chemical vapor deposition (CVD) system. In the first step, multilayer graphene (MLG) was grown on nickel substrates by changing the methane gas flow rate and growth time. In the second step, the CNTs were then grown on the synthesized MLG surface previously. Both the Ni catalyst film thickness and H2 gas flow rate were changed to investigate their effects on the growth densities and average diameters of the hybrid structures. Structural and morphological analysis of both MLG and MLG/CNT hybrid structures were determined using X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), energy-dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), and Raman analysis. As the Ni catalyst film thickness was increased, CNTs grew more densely on the MLG. It was observed that CNTs with smaller diameters and longer lengths formed with increasing H2 gas flow rate. This hybrid structure is useful in electronic, optoelectronic, and energy storage applications.

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