Electrochemical comparison between SnO2 and Li2SnO3 synthesized at high and low temperatures

Li2SnO3 has been synthesized at 1000 °C from Li2CO3 and SnO2 (high temperature form - HT) and it has also been prepared from ball-milled SnO2 and Li2CO3 at 650 °C (low temperature form - LT). The Li2SnO3 materials have been tested as a negative electrode for possible use in a Li-ion cell and their electrochemical behaviour has been compared with that of SnO2. In theory, Li2SnO3 and SnO2 should be able to cycle the same number of lithium atoms per tin atom but on the initial discharge SnO2 has inserted more lithium than Li2SnO3. During the initial discharge of SnO2 and Li2SnO3, a side electrochemical reaction seems to be occurring. The resultant compound apparently inserts lithium reversibly for potentials around 1 V; however, cycling from 0.02–2 V significantly degrades performance compared to 0.02–1 V. Li2SnO3 (HT) allows the de-insertion of more lithium than Li2SnO3 (LT) and SnO2 in the first charge.