The main goal of this project was to investigate the electrochemical performance of functionalized germanane-carbon composites in sodium-ion batteries (SIBs), complemented by select studies in lithium-ion batteries (LIBs), to understand their structure-property relationships. Initially, the focus was on modifying surface chemistry using carbon materials and exploring their impact on the electronic properties. As the project progressed, the emphasis shifted toward synthesizing and evaluating novel 2D monoelemental materials, specifically silicane (SiH) and germanane (GeH), through a scalable and cost-effective process.
We successfully synthesized innovative 2D SiH and GeH materials with various compositions (Si0.25Ge0.75H Si0.50Ge0.50H and Si0.75Ge0.25H) via chemical exfoliation of their Zintl phases. These materials displayed large surface areas, high mechanical flexibility, and fast electron mobility, positioning them as promising candidates for energy storage applications. Among the tested compositions, the Si0.50Ge0.50H electrode delivered the best performance, achieving a discharge capacity of 1059 mAh g−1 after 60 cycles at a current density of 75 mA g−1.
To further understand the lithiation/delithiation mechanisms, we performed ex-situ electrochemical analysis on the Si0.50Ge0.50H material. The study provided key insights into the c-Li15(SixGe1-x)4 phase after lithiation and the a-Si0.50Ge0.50 phase after delithiation, offering new perspectives on the (de)lithiation processes in germanane-silicane alloys. These findings deepen our understanding of their electrochemical behavior and open up opportunities for future research.
Overall, this project made significant advancements in synthesizing and characterizing germanane-based materials and highlighted their potential in energy storage applications, particularly for use in rechargeable batteries. These breakthroughs lay the groundwork for further exploration and application of 2D materials in next-generation battery technologies.
