Direct electrodeposition of ionic liquid-based template-free SnCo alloy nanowires as an anode for Li-ion batteries

SnCo alloy nanowires were successfully electrodeposited from SnCl2-CoCl2-1-ethyl-3-methylimidazolium chloride (EMIC) ionic liquid without a template. The nanowires were obtained from the molar ratio of 5:40:60 for SnCl2:CoCl2:EMIC at -0.55 V and showed a minimum diameter of about 50 nm and lengths of over 20 m. The as-fabricated SnCo nanowires were about 70 nm in diameter and featured a Sn/Co weight ratio of 3.85:1, when used as an anode for a Li-ion battery, they presented respective specific capacities of 687 and 678 mAhg(-1) after the first charge and discharge cycle and maintained capacities of about 654 mAh<bold>g</bold>-1 after 60 cycles and 539 mAhg(-1) after 80 cycles at a current density of 300 mAg(-1). Both the nanowire structure and presence of elemental Co helped buffer large volume changes in the Sn anode during charging and discharging to a certain extent, thereby improving the cycling performance of the Sn anode.