Application of Tris(2,2,2-Trifluoroethy) Phosphates as Flame-Retardant Additives for Lithium-Ion Rechargable Batteries

摘要

Rechargeable lithium ion batteries are one of the favorite energy storage devices for upcoming mobile electric devices and hybrid vehicles because of their high energy density and long cycle life time. The electrolytes for these batteries consist of flammable organic solvents which are serious hazard under abusive conditions especially for large-scale lithium batteries. To reduce flammability of electrolyte of lithium-ion batteries and resolve safety problem, Tris(2, 2, 2-trifluoroethyl) phosphate (TFP) was synthesized and was add into electrolytes as additive. It was found that the SET decreased significantly with the increase of the concentration of TFP. When the concentration is over 20% (vol.) electrolytes are nonflammable. At the same time, with the concentration increasing, the ion-conductivity decreased and the discharge capacity also came down slowly. The electrochemistry stability of LiCoO2 cathode was improved. According to our study, it is possible to find a cosolvent or additive that makes nonflammable lithium-ion electrolyte be put into practice.