Electrochemical properties of amorphous GeO x -C composite microspheres prepared by a one-pot spray pyrolysis process

Abstract Amorphous GeO 2 -GeO-C (GeO x -C) composite powders, containing a small amount of the GeC phase, are prepared by a one-pot spray pyrolysis process. The GeO x -C composite powders have a completely spherical shape and are non-aggregated. The Ge 3d components in the XPS spectrum of the composite occupy 53.3%, 40.1%, and 6.6% of the total for GeO 2 , GeO, and GeC, respectively. The amount of amorphous carbon in the GeO x -C composite powder is estimated at 18.3%, based on the TG and XPS analysis. The initial discharge and charge capacities of the GeO x -C composite powders at a current density of 1 A g −1 are 1873 and 908 mA h g −1 , respectively. The discharge capacities of the GeO x -C composite and commercial GeO 2 powders for the 1200th cycle are 723 and 169 mA h g −1 , respectively, and their corresponding capacity retentions from the 2nd cycle are 70.1% and 19.0%, respectively. The high structural stability of the composite during repeated lithium insertion and desertion processes results in excellent long-term cycling performance.