LiPF6/methyl difluoroacetate electrolyte with vinylene carbonate additive for Li-ion batteries |
| |
Authors: | Kazuya SatoLiwei Zhao Shigeto OkadaJun-ichi Yamaki |
| |
Affiliation: | a Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, 6-1 Kasuga-Koen, Kasuga, Fukuoka 816-8580, Japan b Institute for Materials Chemistry and Engineering, Kyushu University, 6-1 Kasuga-Koen, Kasuga, Fukuoka 816-8580, Japan |
| |
Abstract: | A methyl difluoroacetate (MFA)-based LiPF6 solution was applied as an electrolyte to improve the thermal stability of Li-ion batteries. The addition of vinylene carbonate (VC) improved the electrochemical characteristics of the electrolyte significantly, and satisfactory reversible capacity and cycling performance were obtained with a graphite negative electrode. The thermal stability of the electrolytes was investigated with DSC. Regardless of whether or not VC was used, the electrolyte exothermically decomposed at a temperature higher than 450 °C. The thermal behavior of a mixture of lithiated graphite and VC-added electrolyte was also studied in detail. The ratio between the electrolyte and the electrode was a dominant factor in the heat generation of the mixture. A sharp exothermic peak at about 330 °C was observed when the electrode was superabundant, but the heat value was much smaller than that obtained with 1 mol dm−3 LiPF6/EC-DMC electrolyte under the same conditions. When the electrolyte was superabundant, a mild exothermic decomposition of the electrolyte became the dominant reaction in the mixture. X-ray photoelectron spectroscopic analysis was carried out on delithiated graphite electrodes to study the effect of VC additive on solid electrolyte interphase (SEI) modification. VC-added MFA-based electrolyte was considered to be a good candidate for developing safer Li-ion batteries. |
| |
Keywords: | Li-ion batteries Electrolyte Additive Thermal stability |
本文献已被 ScienceDirect 等数据库收录! |
|