The demand for a stable and compatible redox shuttles for use in lithium-ion batteries has prompted us to explore strategies to tune and improve the properties of redox shuttles. We have studied over 50 new diarylamine derivatives synthesized in our laboratory including one compound in which we introduced trifluoromethyl groups (-CF3) at the positions para to the nitrogen atom in N-ethylphenothiazine (EPT). The high electronegativity of the CF3 group raises the oxidation potential, and its incorporation also significantly increases solubility in battery electrolyte. Here we report 3,7-bis(trifluoromethyl)-N-ethylphenothiazine (BCF3EPT) as a new redox shuttle, which we have observed to have the highest reported solubility in battery electrolyte of all redox shuttles that maintain extended overcharge performance. We have compared its performance with 1,3-di-tert-butyl-2,5-dimethoxybenzene (DBB), EPT, and other robust redox shuttles. In our hands, overcharge cycling of BCF3EPT far surpasses any reported redox shuttle, and - because it can be dissolved at higher concentrations - it tolerates faster charging rates than both DBB and EPT.
|Title of host publication||Materials Challenges for Energy Storage Across Multiple Scales|
|Number of pages||6|
|State||Published - 2015|
|Event||2014 MRS Fall Meeting - Boston, United States|
Duration: Nov 30 2014 → Dec 5 2014
|Name||Materials Research Society Symposium Proceedings|
|Conference||2014 MRS Fall Meeting|
|Period||11/30/14 → 12/5/14|
Bibliographical notePublisher Copyright:
© 2015 Materials Research Society.
ASJC Scopus subject areas
- Materials Science (all)
- Condensed Matter Physics
- Mechanics of Materials
- Mechanical Engineering