Na-iyon bataryalarda çekirdek - kabuk yapıların elektrokimyasal özelliklere etkisinin araştırılması

In this thesis, the structural and electrochemical properties of lithium-ion (Li-ion) and sodium-ion (Na-ion) batteries, which play a critical role in modern energy storage technologies, were investigated. Although Li-ion batteries offer high energy density and long cycle life, limited lithium resources and high costs restrict their sustainability. In this context, sodium, being abundant and low-cost, makes Na-ion batteries a promising alternative for future applications. However, the large ionic radius of Na⁺ requires the development of suitable electrode materials. In this study, Na₀.₆₇Mn₀.₅Fe₀.₄₂Ti₀.₀₈O₂ was synthesized as a cathode material, and its surface was modified with TiO₂ and Al₂O₃ coatings to form a core–shell architecture. Structural and morphological characterizations by SEM, EDX, FTIR, Raman, XRD, and XPS confirmed homogeneous coatings and preserved crystallinity. Electrochemical tests revealed that TiO₂ enhanced ion diffusion and conductivity, while Al₂O₃ improved surface stability and cycle life. Overall, the core–shell design was shown to enhance capacity retention and cycling stability in Na-ion batteries.