Amorphous GeO2@C composite anodes for long cycling stability and performance in Li-ion batteries

Amorphous GeO2@C anode materials were successfully prepared from commercial GeO2 and C6H12O6.H2O by a hydrothermal method combined with sintering under nitrogen atmosphere protection. The anode materials showed an ideal spherical shape of about 3 μm and their surface was uniformly covered with C. GeO2@C composite anodes exhibited better storage performance for Li-ion batteries. The discharge-specific capacities of GeO2@C-3 sample were 1143, 1049, 776, 551, and 308 mAh g-1 at current densities of 0.2, 0.5, 1, 2, and 5 A g-1, and restored to 1136 mAh g-1 when the current density returned to 0.2 A g-1. The reversible specific capacity was 756 mAhg-1 after 1000 cycles at a current density of 1 A g-1. The GeO2@C anode was stable in the process of charge and discharge, and no obvious pulverization occurred. GeO2@C composites stabilized the electrochemical properties through carbon and amorphous structure to improve the overall electrical conductivity in Li+ embedding/de-embedding processes.