Yazar "Whba R." seçeneğine göre listele

Listeleniyor 1 - 2 / 2
  • Küçük Resim Yok
    Öğe
    Exploring the Impact of Lanthanum on Sodium Manganese Oxide Cathodes: Insight into Electrochemical Performance
    (John Wiley and Sons Inc, 2024) Whba R.; Altundag S.; Aydin M.G.; Kalyoncuoglu B.; Ozgul M.; Depci T.; Altin S.
    This investigation focuses on nominally La-doped Na0.67MnO2, exploring its structural, electrochemical, and battery characteristics for Na-ion batteries. X-ray diffraction analysis reveals formation of composite materials containing three distinct phases: P2-Na0.67MnO2, NaMn8O16, and LaMnO3. The bond structures of the powders undergo scrutiny through Fourier-transform infrared and Raman analyses, revealing dependencies on the NaO, MnO, and LaO structures. X-ray photoelectron spectroscopy and energy-dispersive X-ray dot mapping analyses show that the La ions are unevenly dispersed within the samples, exhibiting a valence state of 3+. Half-cell tests unveil similarities in redox peaks between the cyclic voltammetry analysis of La-doped samples and P2-type Na0.67MnO2, with a reduction in peak intensities as La content increases. Electrochemical impedance spectroscopy model analysis indicates direct influences of La content on the half-cell's resistive elements values. The synergistic effect of composite material with multiple phases yields promising battery performances for both half and full cells. The highest initial capacity value of 208.7 mAh g?1, with a 57% capacity fade, among others, is observed, and it diminishes with increasing La content. Full cells are constructed using an electrochemically presodiated hard carbon anode, yielding a promising capacity value of 184.5 mAh g?1 for sodium-ion battery studies. © 2024 Wiley-VCH GmbH.
  • Küçük Resim Yok
    Öğe
    Intrinsic challenges and strategic approaches for enhancing the potential of natural rubber and its derivatives: A review
    (Elsevier B.V., 2024) Whba R.; Su'ait M.S.; Whba F.; Sahinbay S.; Altin S.; Ahmad A.
    Natural rubber (NR) and its derivatives play indispensable roles in various industries due to their unique properties and versatile applications. However, the widespread utilization of NR faces intrinsic challenges such as limited mechanical strength, poor resistance to heat and organic solvent, poor electrical conductivity, and low compatibility with other materials, prompting researchers to explore enhancing its performance. Modified NRs (MNRs) like cyclization, deproteinization, chlorination, epoxidation, or grafting NR demonstrated a few enhanced merits compared to NR. However, various strategies, such as blending, vulcanization, crosslinking, grafting, plasticization, reinforcement, and nanostructuring, overcame most drawbacks. This review comprehensively examines these challenges and delves into the modification strategies employed to enhance the properties and expand the applications of NR and its derivatives. Furthermore, the review explores future visions for the NR industry, emphasizing integrating advanced modification techniques, adopting sustainable practices, and promoting circular economy principles. By elucidating the inherent challenges, outlining effective modification strategies, and envisioning future trajectories, this review provides valuable insights for stakeholders seeking to navigate and contribute to the sustainable development of the NR sector. © 2024 Elsevier B.V.