Synthesis of Multiphase Cu₃Ge/GeO_x/CuGeO₃ Nanowires for Use as Lithium-Ion Battery Anodes

Multiphase nanowires composed of Cu₃Ge, GeO_x, and CuGeO₃, obtained through the thermochemical reduction of CuGeO₃, are investigated as anode materials for lithium-ion batteries. Initially, CuGeO₃ nanowires are prepared by using a facile hydrothermal process without the use of any templates or surfactants. The as-prepared CuGeO₃ nanowires are demonstrated to be single-crystalline with a diameter of around 70nm and a length of 0.5-2μm. Subsequently, multiphase Cu₃Ge/GeO_x/CuGeO₃ nanowires are prepared through the controlled thermochemical reduction of the as-prepared CuGeO₃ nanowires under a H₂ atmosphere at 250°C. Upon thermochemical reduction, the wire-shaped morphology is retained, but the phase partially transforms to a mixture of crystalline Cu₃Ge nano-domains (<10nm) with high electronic conductivity and amorphous GeO_x. The newly generated multiphase nanowires exhibit enhanced cycle stability with high lithium-storage capability compared to that of the as-prepared CuGeO₃ nanowires.