Germanium nanoparticles (NPs) are obtained by direct oxidation of a solid-state Na12Ge17 Zintl phase used as germanium precursor. Alcohols are chosen as oxidizing agents in a room-temperature process. The materials are characterized by X-ray diffraction, transmission electron microscopy, and Raman spectroscopy. The nature of the alcohol influences the final products and their crystallinity. The germanium NPs, tested as anodic materials for lithium ion batteries, display interesting behaviors with initial capacities up to 1,530 mAh g-1.