N-doped CNT assisted GeO₂-Ge nanoparticles as a high-capacity and durable anode material for lithium-ion batteries

Germanium-based materials are emerging as promising anode candidates for lithium-ion batteries (LIBs) due to their high theoretical capacity, excellent electrical conductivity, and efficient lithium-ion diffusion at room temperature. However, their practical application is hindered by substantial volume changes during cycling, leading to poor cycling stability and diminished electrochemical performance. This study successfully created a GeO₂-Ge@NCNT composite using a cost-effective and environmentally friendly GeO₂ precursor through a hydrothermal method. N-doped carbon nanotubes (NCNT) were utilized to enhance electrochemical activity by providing additional active sites and improving structural stability. The GeO₂-Ge@NCNT anode demonstrated remarkable cycling stability with a capacity of 1017 mA h g^-1 at a current density of 100 mA g^-1 after 100 cycles, maintaining a coulombic efficiency of 98.15% and a capacity retention of 71.15% (vs. 2^nd cycle discharge capacity). Moreover, C-rate analysis showed exceptional rate capability and consistent long-term cycling performance. This research presents a sustainable and scalable method for producing high-performance Ge-based anodes for next-generation lithium-ion battery technologies.