Yazar "Bhatti, Ali Hussain Umar" seçeneğine göre listele

Listeleniyor 1 - 2 / 2
  • Küçük Resim Yok
    Öğe
    Evaluation of the Effect of Precursor NMC622@TiO2 Core-Shell Powders Using a Prelithiated Anode from Figure Seeds: Spotlight on Li-ion Full-Cell Performance
    (Amer Chemical Soc, 2024) Whba, Rawdah; Dogan, Ebru; Moeez, Iqra; Bhatti, Ali Hussain Umar; Akbar, Muhammad; Chung, Kyung Yoon; Altin, Emine
    In this study, innovative electrode materials for lithium-ion batteries (LIBs) were developed and characterized, demonstrating significant performance enhancements. Initially, NMC622@TiO2 was synthesized using a wet-chemical method with titanium(IV) ethoxide as the Ti source. Advanced structural investigations confirmed the successful formation of a core@shell structure with negligible cation mixing (Li+/Ni2+) at the NMC622 surface, contributing to enhanced electrochemical performance. Subsequently, carbon-based anode materials were produced from biomass, specifically figure seeds, and subjected to high-temperature heat treatment. The resulting powders exhibited dominant graphitic properties, evidenced by a Raman I D/I G ratio of 0.5. Electrochemical evaluations of both electrode materials were conducted using half-cell configurations. The optimization of the TiO2 coating process was assessed through half-cell performance metrics and diffusion rates calculated from galvanostatic intermittent titration technique (GITT) experiments. The final phase focused on full-cell design, employing a prelithiation strategy for anodes using a direct contact technique. Optimization of the prelithiation process led to the assembly of full cells combining NMC622/prelithiated figure-seed anodes and NMC622@TiO2/prelithiated figure-seed anodes. The results revealed that TiO2-coated NMC622, paired with prelithiated carbon anodes derived from figure seeds, delivered superior performance compared to uncoated NMC622 full cells. This study underscores the potential of biomass-derived carbon anodes and TiO2 coatings in enhancing the efficiency and performance of LIBs.
  • Küçük Resim Yok
    Öğe
    Revealing the Role of Ruthenium on the Performance of P2-Type Na0.67Mn1-xRuxO2 Cathodes for Na-Ion Full-Cells
    (Wiley-V C H Verlag Gmbh, 2024) Altin, Emine; Moeez, Iqra; Kwon, Eunji; Bhatti, Ali Hussain Umar; Yu, Seungho; Chung, Kyung Yoon; Arshad, Muhammad
    Herein, P2-type layered manganese and ruthenium oxide is synthesized as an outstanding intercalation cathode material for high-energy density Na-ion batteries (NIBs). P2-type sodium deficient transition metal oxide structure, Na0.67Mn1-xRuxO2 cathodes where x varied between 0.05 and 0.5 are fabricated. The partially substituted main phase where x = 0.4 exhibits the best electrochemical performance with a discharge capacity of approximate to 170 mAh g(-1). The in situ X-ray Absorption Spectroscopy (XAS) and time-resolved X-ray Diffraction (TR-XRD) measurements are performed to elucidate the neighborhood of the local structure and lattice parameters during cycling. X-ray photoelectron spectroscopy (XPS) revealed the oxygen-rich structure when Ru is introduced. Density of States (DOS) calculations revealed the Fermi-Level bandgap increases when Ru is doped, which enhances the electronic conductivity of the cathode. Furthermore, magnetization calculations revealed the presence of stronger Ru & horbar;O bonds and the stabilizing effect of Ru-doping on MnO6 octahedra. The results of Time-of-flight secondary-ion mass spectroscopy (TOF-SIMS) revealed that the Ru-doped sample has more sodium and oxygenated-based species on the surface, while the inner layers mainly contain Ru-O and Mn-O species. The full cell study demonstrated the outstanding capacity retention where the cell maintained 70% of its initial capacity at 1 C-rate after 500 cycles.