Combinatorial Electrodeposition of Ternary Cu–Sn–Zn Alloys

Abstract

Active-inactive alloy systems (such as Cu–Sn–Zn) have been proposed to replace graphitic negative electrodes in commercial lithium-ion batteries due to their high theoretical capacity and relatively good cyclability. The performance of these electrode materials is largely determined by their composition. Identifying the optimal composition that provides both large capacity and good cyclability requires the testing of tens, hundreds or even thousands of different alloys. Combinatorial deposition and screening techniques lend themselves well to this kind of optimization study. Galvanostatic deposition in an electrochemical Hull cell is used to fabricate a composition-spread film of binary Sn–Zn alloys. A second step involving a water gun and weak copper sulfate solution is used to achieve a composition spread film of ternary Cu–Sn–Zn alloys. Energy-dispersive spectroscopy and X-ray diffraction are used to characterize the electrodeposited films. The significance and uniqueness of this work is illustrated by our ability to perform combinatorial material science simply and inexpensively. In addition, a phenomenological model is presented to describe the deposition process. The success of the phenomenological model demonstrates we have an understanding, albeit rudimentary, of the immersion deposition process.