Vinyl-Tris-(methoxydiethoxy)silane as an effective and ecofriendly flame retardant for electrolytes in lithium ion batteries

In this paper, we report a new flame retardant, vinyl-Tris-(methoxydiethoxy)si lane (VTMS), for use in electrolytes of lithium ion batteries. Burning tests showed that the addition of VTMS at 5-15 vol.% into the currently used electrolyte could effectively reduce the flammability. As long as the added amount was below 10%, electrochemical performance such as reversible capacity and cycling showed little change. In addition, differential scanning calorimetry (DSC) in combination with X-ray photoelectron spectroscopy (XPS) disclosed that VTMS participated in the formation of the surface film on the cathode, which played a pivotal role in markedly improving the thermal stability of the LiCoO2 cathode. This kind of ecofriendly compound provides a new promising direction for the development of organic additives to improve the safety of lithium ion batteries. (C) 2008 Elsevier B.V. All rights reserved.