Skip to main content
Open Access Publications from the University of California

Poly(vinylidene fluoride) (PVDF) Binder Degradation in Li-O2Batteries: A Consideration for the Characterization of Lithium Superoxide

  • Author(s): Papp, JK
  • Forster, JD
  • Burke, CM
  • Kim, HW
  • Luntz, AC
  • Shelby, RM
  • Urban, JJ
  • McCloskey, BD
  • et al.

© 2017 American Chemical Society. We show that a common Li-O2battery cathode binder, poly(vinylidene fluoride) (PVDF), degrades in the presence of reduced oxygen species during Li-O2discharge when adventitious impurities are present. This degradation process forms products that exhibit Raman shifts (∼1133 and 1525 cm-1) nearly identical to those reported to belong to lithium superoxide (LiO2), complicating the identification of LiO2in Li-O2batteries. We show that these peaks are not observed when characterizing extracted discharged cathodes that employ poly(tetrafluoroethylene) (PTFE) as a binder, even when used to bind iridium-decorated reduced graphene oxide (Ir-rGO)-based cathodes similar to those that reportedly stabilize bulk LiO2formation. We confirm that for all extracted discharged cathodes on which the 1133 and 1525 cm-1Raman shifts are observed, only a 2.0 e-/O2process is identified during the discharge, and lithium peroxide (Li2O2) is predominantly formed (along with typical parasitic side product formation). Our results strongly suggest that bulk, stable LiO2formation via the 1 e-/O2process is not an active discharge reaction in Li-O2batteries.

Many UC-authored scholarly publications are freely available on this site because of the UC Academic Senate's Open Access Policy. Let us know how this access is important for you.

Main Content
Current View