Comparative Analysis of Electronic Properties in Si/GO and Si/rGO Composite Anodes: The Role of Restored Conductivity in Battery Performance

This research investigates the synthesis and comparative electronic properties of Silicon/Graphene Oxide (Si/GO) and Silicon/Reduced Graphene Oxide (Si/rGO) composite anodes. While silicon provides a high theoretical capacity, its 300% volume expansion during lithiation necessitates a robust structural buffer. Our approach utilizes GO as a template, integrated with silica derived from Tetraethyl Orthosilicate (TEOS).

A central focus of this study is the critical transition from the insulating GO phase to the conductive rGO phase. Structural validation via XRD confirmed the oxidation of graphite to GO with a d-spacing of 8.24 Å. UV-Vis spectroscopy and Tauc plot analysis identified a wide direct optical band gap of 4.35 eV for the GO matrix. This high value confirms an insulating state dominated by hybridized defects, which, while structurally stable, limits electron transport.

To restore conductivity, a magnesiothermic reduction process was employed to simultaneously convert the TEOS-derived into nanostructured silicon and reduce the GO into rGO. This process removes oxygen functional groups and restores the hybridized carbon network. Comparative analysis shows that while the GO/Si intermediate acts as a stable structural scaffold, the final rGO/Si composite is essential for electrochemical performance. The reduction step significantly enhances the electrical conductivity and charge-transfer kinetics of the anode. These results prove that the controlled transition from the insulating GO phase to the conductive rGO phase is a vital "invention" in the synthesis of stable, high-rate capability anodes for next-generation lithium-ion batteries.

This work was supported by the Ministry of Science and Higher Education of the Russian Federation, project no. FSER-2025-0005.