Synthesis of hollow GeO2 nanostructures, transformation into Ge@C, and lithium storage properties

In this work, we synthesize mesoporous and hollow germanium@carbon nanostructures through simultaneous carbon coating and reduction of a hollow ellipsoidal GeO2 precursor. The formation mechanism of GeO 2 ellipsoids and the ratio of Ge4+ to Sn4+ as the starting materials are also investigated. Compared to the solid ellipsoidal Ge@carbon (Ge@C-3), the hollow ellipsoidal Ge@C-1 sample exhibits better cycling stability (100% capacity retention after 200 cycles at the 0.2 C rate) and higher rate capability (805 mA h g-1 at 20 C) compared to Ge@C-3 due to its unique hollow structure; therefore, this hollow ellipsoidal Ge@carbon can be considered as a potential anode material for lithium ion batteries. © 2013 The Royal Society of Chemistry.