N-substituted phenothiazine derivatives: How the stability of the neutral and radical cation forms affects overcharge performance in lithium-ion batteries

Kishore Anand Narayana, Matthew D. Casselman, Corrine F. Elliott, Selin Ergun, Sean R. Parkin, Chad Risko, Susan A. Odom

Research output: Contribution to journalArticlepeer-review

58 Scopus citations

Abstract

Phenothiazine and five N-substituted derivatives were evaluated as electrolyte additives for overcharge protection in LiFePO4/synthetic graphite lithium-ion batteries. We report on the stability and reactivity of both the neutral and radical-cation forms of these six compounds. While three of the compounds show extensive overcharge protection, the remaining three last for only one to a few cycles. UV/Vis studies of redox shuttle stability in the radical cation form are consistent with the overcharge performance: redox shuttles with spectra that show little change over time exhibit extensive overcharge performance, whereas those with changing spectra have limited overcharge protection. In one case, we determined that a C-N bond cleaves upon oxidation, forming the phenothiazine radical cation and leading to premature overcharge protection failure; in another case, poor solubility appears to limit protection.

Original languageEnglish
Pages (from-to)1179-1189
Number of pages11
JournalChemPhysChem
Volume16
Issue number6
DOIs
StatePublished - Apr 27 2015

Bibliographical note

Publisher Copyright:
© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Keywords

  • overcharge protection
  • phenothiazine
  • radical cations
  • redox shuttles
  • substituent effects

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics
  • Physical and Theoretical Chemistry

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