Study the Structure, Optical, and Electrochemical Properties of Germanium Oxide/Graphene Nanoplatelet Composite for Energy Storage Applications

Germanium oxide (GeO₂) nanoparticles exhibit a high theoretical discharge capacity of 2152 mAh g⁻¹, making them promising anode materials for lithium-ion batteries. However, their practical application is hindered by severe volume expansion during charge/discharge cycles, leading to structural degradation and capacity fading. To address this challenge, GeO₂/graphene nanoplatelet (GNP) composite is synthesized via a modified sonochemical technique. The structural, optical, thermal, and electrochemical properties of GeO₂ and GeO₂/GNP composites are systematically investigated. The incorporation of GNP improves the structural integrity of GeO₂ by mitigating volume changes, enhancing electronic conductivity, and increasing thermal stability. Optical studies reveal a slight bandgap widening, while Fourier transform infrared spectroscopy analysis confirms strong interfacial interactions between GeO₂ and GNP. Electrochemical evaluation demonstrates that the composite retained a discharge capacity of 181 mAh g⁻¹ after 100 cycles, significantly improving the cyclic stability of GeO₂ anodes. These findings highlight the potential of GeO₂/GNP composites as high-performance anode materials for energy storage applications.