Improvement of high voltage cycling performance and thermal stability of lithium-ion cells by use of a thiophene additive

This study demonstrates that the addition of thiophene improves the cycle life of lithium-ion cells at high voltage. Electrochemical impedance spectroscopy results suggest that addition of thiophene significantly suppresses the increase of the charge transfer resistance that occurs during cycling up to high voltage. Differential scanning calorimetric studies showed that the thermal stability of fully charged LiCOO2 cathode was also enhanced in the presence of thiophene. (C) 2009 Elsevier B.V. All rights reserved.