| 研究実績の概要 |
Nonflammable electrolytes could intrinsically eliminate the battery safety concerns, but generally leads to compromised battery performance owing to ineffectively passivation on the carbonaceous anode. By introducing the ethylene carbonate-like structure, we have successfully designed and synthesized a nonflammable cyclic phosphate solvent that can not only effectively passivate carbonaceous anodes, but also passivate an Al cathode current collector even with corrosive lithium salt LiN(SO2F)2. Without using any SEI-forming additive or co-solvent, for the first time, a highly reversible and stable cycling of a graphite electrode in such a cyclic phosphate-based nonflammable electrolyte has been achieved.
|
| 現在までの達成度 (区分) |
現在までの達成度 (区分)
2: おおむね順調に進展している
理由
During the last 6 months, by mimicking the ethylene carbonate-like structure, we have successfully designed and synthesized a nonflammable cyclic phosphate solvent, namely 2-methoxy-1,3,2-dioxaphospholane 2-oxide (MDP). The MDP solvent has shown some promising results during the preliminary test, but the anode passivation was not very satisfactory. Thus, in order to improve the performance, the fluorinated group was introduced to synthesize 2-(2,2,2-trifluoroethoxy)-1,3,2-dioxaphospholane 2-oxide (TFEP), the resulting electrolyte can not only effectively passivate carbonaceous anodes, but also passivate an Al cathode current collector even with corrosive lithium salt LiN(SO2F)2. We are currently working on evaluation the full cell performance in this electrolyte.
|
| 今後の研究の推進方策 |
In the future, the fluorinated groups are proposed to introduce to the cyclic phosphate at different position including and 2-methoxy-4-trifluoromethyl-1,3,2-dioxaphospholane¬-2-oxide (MTFP) and 2-methoxy-4-fluoro-1,3,2-dioxaphospholane¬-2-oxide (FMDP), with the hope to improve the SEI formation capability and high voltage stability. The viscosity, ionic conductivity, flammability of the resulting electrolytes will be investigated. The charge-discharge, rate capability and cycling performance will be fully evaluated for both half and full cells. Scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR) will be used to study the surface composition and structure change after long-term cycling.
|
