A Combinatorial Study of the Sn-Si-C System for Li-Ion Battery Applications

In the present work three pseudobinary libraries of the Sn-Si-C system were produced using combinatorial methods. X-ray diffraction was used to study the structure of these libraries and Mossbauer spectroscopy was employed to probe the atomic environment. Cyclic voltammetry measurements were performed using a multichannel pseudopotentiostat to study the behavior of these materials as negative electrodes for Li-ion batteries. These three libraries were compared in terms of the phases formed, amorphous vs. crystalline structure, the reversible capacity as a function of composition and the capacity retention. The addition of carbon to Sn-Si inhibits the aggregation of Sn into regions of relatively pure tin. This minimization of free tin has the effect of improving cycleability by reducing the adverse effects of volume expansion, by eliminating two-phase coexistence regions during delithiation and lithiation. (C) 2012 The Electrochemical Society. [DOI: 10.1149/2.075206jes] All rights reserved.