Graphite-based composites decorated with SnO₂ nanoparticles and investigation of their electrochemical properties

In this thesis, expanded graphite (EG) and EG/SnO₂ composites were successfully synthesized and comprehensively characterized for potential use in lithium-ion batteries. The primary objective of this study is to address the significant volume expansion problem of SnO₂ during lithium-ion intercalation, which negatively affects cycle stability. To mitigate this issue, SnO₂ was combined with expanded graphite to create a homogeneous composite structure. In the experimental work, three different EG/SnO₂ composites with varying SnO₂ content were produced. The structural properties of the composites were analyzed in detail using XRD, SEM, and Raman spectroscopy. XRD and SEM analyses demonstrated that SnO₂ nanoparticles were homogeneously distributed between graphite layers. Raman spectroscopy results confirmed that the structural order of expanded graphite was disrupted, and the interlayer spacing increased. TG/DTG analyses provided insights into the SnO₂ content and thermal stability of the composites. Electrochemical characterization, including charge-discharge tests and cyclic voltammetry analyses, revealed that EG/SnO₂ composites exhibited superior cycling stability compared to pure SnO₂ electrodes. Among the composites, EG/SnO₂-60 demonstrated the best performance by offering a balanced SnO₂ ratio, long cycle life, and high capacity. This thesis contributes significantly to the development of high-performance and long-lasting anode materials for lithium-ion batteries. The findings suggest that EG/SnO₂ composites can be considered promising candidates for next-generation energy storage systems.