Three-dimensional nanoporous Ge/Sn dual-framework as novel anode for high-performance lithium-ion batteries

Due to the low conductivity, large volume change and fast capacity decay of high-capacity Ge anode in the cycle process, its commercial application in Li-ion battery is seriously restricted. Herein, nanoporous Ge/Sn alternating dual-framework is designed by taking advantage of the low solid solubility between pairwise component elements. When employed as an anode material for Li-ion batteries, the material delivers excellent reversible capacity of 1 307.8 mAh·g⁻¹ after cycling at 100 mA g⁻¹ for 100 cycles and presents 983.3 mAh g⁻¹ after cycling at 1 000 mA g⁻¹ for 200 cycles. In-situ TEM and ex-situ Raman tests reveal that Li ion can react with the Ge/Sn dual network material to form a novel product GeLi₂Sn, which provides a new reaction path during the lithiation process and greatly promotes the electrochemical reaction, ensuring good electrochemical capacity and stability. The work provides a new strategy for developing dual-network electrode materials and new reaction paths of novel materials in the lithiation process, which will promote the research of Ge-based materials in Li-ion battery and other energy storage fields.