Size tunable Ga-Ge nanowires for Li-ion battery prepared by in situ alloying in ionic liquid electrodeposition

Germanium (Ge)-based materials have become important candidates for high-performance Li ion battery applications; however, the cycling performance and rate capability require further improvement to meet the fast development of mobile devices. Ge-based alloy nanowires provide a high surface to volume ratio as well as optimal alloy materials, both of which are advantageous for obtaining high-performance Li ion battery anodes. In this paper, we report in situ Ga-Ge alloying in ionic liquid electrodeposition to prepare size tunable Ga-Ge nanowires. The size of the seed Ga particles increases with solution temperature, thus leading to increasing diameter and length of the Ga-Ge nanowires. The smallest diameter nanowires grown at a Ga deposition temperature of 25 degrees C yield the best cycling performance (1101 mA h g(-1) after 100 cycles at 0.32 A g(-1)) and rate capability (728 mA h g(-1) at 16 A g(-1)) among all four tested samples.