On the nature of Li insertion in tin composite oxide glasses

Tin composite oxide (TCO) glass, Sn1.0Al0.4B0.56P0.4O3.6, is a high capacity lithium storage medium that may perform as the next generation of anodes in Li-ion batteries. By using X-ray absorption spectroscopy in conjunction with lithium-7 nuclear magnetic resonance, we have obtained a picture of the Li insertion and deinsertion process in TCO compared to that in SnO, and show that these processes are more complex than was originally thought. Our results demonstrate the significance of oxygen participation in the reversible reactions at nanophase Li-Sn or Li-Sn-O centers, and suggest that the presence of a quasi-flexible Al coordination environment in the glass may enhance the cycling properties. (C) 1999 The Electrochemical Society. S1099-0062(99)02-022-2. All rights reserved.