Single-bath electrodeposition of a combinatorial library of binary Cu1-xSnx alloys

Electrodeposition from a single bath in a single run was used to create a combinatorial library of binary Cu-Sn alloys. Electron microprobe and X-ray diffraction studies were used to determine the average stoichiometry and the phases present as a function of position on the substrate foil. The deposited film follows the Cu-Sn phase diagram, except that Cu41Sn11 was observed instead of Cu3Sn. Electrodes with various average stoichiometry were punched from the film and tested as negative electrodes for Li-ion cells. Electrodes taken from the high Sn content area of the electrodeposited film display high capacity (similar to600 mAh/g) but poor capacity retention with cycling. Electrodes taken from the high Cu content area of the film display reduced capacity (similar to300 mAh/g) with dramatically improved capacity retention. (C) 2003 The Electrochemical Society.