Cathode- and anode-active poly(nitroxylstyrene)s for rechargeable batteries: P- and n-type redox switching via substituent effects

Takeo Suga, Yong Jin Pu, Shinji Kasatori, Hiroyuki Nishide

Research output: Contribution to journalArticle

107 Citations (Scopus)

Abstract

Three polystyrenes bearing redox-active nitroxide radical(s) in each repeating unit, poly[4-(N-tert-butyl-N-oxylamino)styrene] (1), poly[3,5-di(N-tert-butyl-N-oxylamino)styrene] (2), and poly[4-(N-tert-butyl-N- oxylamino)-3-trifluoromethylstyrene] (3), were synthesized via free radical polymerization of protected precursor styrenic derivatives and subsequent chemical oxidation. The radicals in these polymers were robust at ambient conditions, and the polymers possessed radical densities of 2.97 × 10 21, 4.27 × 1021, and 1.82 × 1021 unpaired electrons/g for 1-3, respectively, resulting in an electrode-active material with a high charge/discharge capacity. Particularly, the dinitroxide functional polymer 2 possessed the highest radical density. Cyclic voltammetry of the poly(nitroxylstyrene) 1 revealed a reversible redox at 0.74 V vs Ag/AgCl, which was assigned to the oxidation of the nitroxide radical to form the oxoammonium cation (p-type doped state). On the other hand, the poly-(nitroxylstyrene) ortho-substituted with the electron-withdrawing trifluoromethyl group 3 showed a reversible redox at -0.76 V, ascribed to the n-type redox pair between the nitroxide radical and the aminoxy anion. Thus, the nitroxide radical polymer could be switched from p-type material suitable for a cathode to n-type material (anode-active) via altering the electron-withdrawing character of the substituents on the poly(nitroxylstyrene). This is the first report of an n-type radical polymer and the first report of using substituent effects to switch the redox behavior of the polymer. This versatile switching ability enables these polymers to function as components of metal-free electrodes in rechargeable batteries.

Original languageEnglish
Pages (from-to)3167-3173
Number of pages7
JournalMacromolecules
Volume40
Issue number9
DOIs
Publication statusPublished - 2007 May 1

ASJC Scopus subject areas

  • Organic Chemistry
  • Polymers and Plastics
  • Inorganic Chemistry
  • Materials Chemistry

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