Mesoporous germanium as anode material of high capacity and good cycling prepared by a mechanochemical reaction

Mesoporous Ge was prepared by mechanochemical reaction of GeO₂ and Mg powders followed by an etching process with HCl solution. It was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and charge-discharge measurement. With a pore-distribution concentrated around 10 nm, the product presents a BET surface area of 49.98 m²/g. When using as an anode material for lithium ion battery, the mesoporous Ge exhibits a reversible capacity of 950 mA h/g and retains a capacity of 789 mA h/g after 20 cycles at a current density of 150 mA/g. The cycleability is significantly improved compared with non-porous Ge.