Yazar "Ekicibil, Ahmet" seçeneğine göre listele

Listeleniyor 1 - 2 / 2
  • [ X ]
    Öğe
    Electronic and magnetic properties of boron substituted CuFeO2 delafossite oxide
    (Taylor & Francis Ltd, 2024) Ezircan, Ali; Aslan, M. Selim; Miyazaki, Hidetoshi; Akyol, Mustafa; Ozkendir, O. Murat; Ekicibil, Ahmet; Ozturk, Hakan
    Synchrotron x-ray diffraction (SR-XRD) and X-ray absorption fine structure spectroscopy (XAFS) were used to investigate the crystal and electronic properties of boron-substituted CuFeO2 material at room temperature. Without boron substitution, the polycrystalline structures of the trigonal (rhombohedral) Rm' over bar m' CuFeO2 (87.7%) and hexagonal 'P63/mmc' (12.3%), which were also present in each sample but in different proportions, were utilised to identify the base material. XRD patterns revealed that, beyond 10% boron substitution, the metal-oxygen bonds (Fe-O and Cu-O) weakened, resulting in the formation of new tetragonal 'I41/amd' CuFe2O4 crystals. Although the CuFeO2 structure was preserved, it is conceivable that the presence of other crystal structures could lead to the formation of new features. This state arose as a result of CuFe2O4 crystallization and the impact of boron activity on the surrounding oxygen structures. By measuring magnetisation at both swept temperatures (10-300 K) and applied magnetic fields (+/- 30 kOe), the magnetic properties of the samples were investigated. In the 10-300 K temperature range, the polycrystalline samples exhibit a ferromagnetic property without a magnetic phase transition. This suggests that replacing B with Fe in CuFe(1-x)BxO(2 )does not influence the primary magnetic property of CuFeO2. The samples' saturation magnetisation (Ms) values gradually fall as the B substitution content increases with Fe. This is because there's a chance that the non-transition metal B in CuFe1-xBxO(2) will boost antiferromagnetic superexchange Cu-O interactions while lowering the p-d exchange interaction.
  • Küçük Resim
    Öğe
    Energy storage performance of LiV3O8/water-in-salt electrolyte/LiNi1/3Co1/3Mn1/3O2 cell for aqueous lithium-ion batteries
    (Elsevier, 2022) Kunduracı, Muharrem; Kılıç Çetin, Selda; Çağlayan, Uğur; Mutlu, Rasiha Nefise; Kaya, Doğan; Ekicibil, Ahmet
    Electrochemical performance of an aqueous lithium-ion battery containing LiV3O8 anode, ‘water-in-salt’ 20 M LiTFSI electrolyte and LiNi1/3Co1/3Mn1/3O2 cathode was studied. In the full cell, the cathode and anode reached a maximum lithiation capacity of 145.8 mAh g?1 and 80 mAh g?1, respectively. The full cell successfully underwent 100–110 cycles before hitting 20% capacity loss limit. The average discharge potential of the cell started at 0.849 V and stayed relatively stable in the next 140 cycles. The first cycle coulombic efficiency was as high as 80% and it stabilized at 99–100% in the subsequent cycles. These are the best numbers ever reported for this anode/cathode couple. This outperformance was achieved thanks to the increased stability of the anode and cathode materials in high molarity ‘water-in-salt’ electrolyte over lower molarity nitrate or sulfate electrolytes previously reported in literature.