Lithia formation mechanism in tin oxide anodes for lithium-ion rechargeable batteries

The lithia formation mechanism in tin oxide anode is investigated using electrochemical measurements and Auger spectroscopy. Based on the charge/discharge capacities for SnO electrode, the atomic ratio of Li to O in lithia is less than 2 at the discharge capacity of 400 mAh/g (similar to 0.9 V). The derivative capacity plots show that the irreversible reaction occurs throughout the entire discharge to 0 V, and the atomic ratio of Li to O is about 1 at similar to 0.8 V and 2 at 0 V. Auger spectroscopy analysis also confirms that the atomic ratio of Li to O approaches to 2 only when discharged to 0 V. Thus, Li2O appears to have formed at 0 V in the first discharge, not similar to 0.8 V as reported previously, such that the initial lithia composition is more like Li2O2 (C) 2009 Elsevier B.V. All rights reserved.