Advanced electrolytes

The effort to develop improved electrolytes that satisfy the requirements of lithium rechargeable batteries has intensified the search for new and advanced electrolytes. The challenges are the optimization of parameters such as long-term cycling stability, rate capability, low temperature performance and safety features. At least the first two aspects are mainly influenced by the electrolyte. Consequently, with the aim to improve the overall performance of lithium ion batteries, one has to address surface film formation and bulk properties of the electrolyte. With the special quality of vinylene carbonate (VC), and the new salt, lithium fluoroalkylphosphate Li[(C 2F 5) 3PF 3], we discuss the properties of the new compounds for advanced electrolytes used in high-energy lithium ion batteries. Results of the electrochemical studies in comparison to standard vinylene carbonate with respect to LiPF 6 are reported. In addition, the influence of Li[(C 2F 5) 3PF 3] on the flammability of non-aqueous electrolytes is demonstrated.