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Title: The Electrochemistry of Fe 3 O 4 /Polypyrrole Composite Electrodes in Lithium-Ion Cells: The Role of Polypyrrole in Capacity Retention

In two series of magnetite (Fe 3O4) composite electrodes, one group with and one group without added carbon, containing varying quantities of polypyrrole (PPy), and a non-conductive polyvinylidene difluoride (PVDF) binder were constructed and then analyzed using electrochemical and spectroscopic techniques. Galvanostatic cycling and alternating current (AC) impedance measurements were used in tandem to measure delivered capacity, capacity retention, and the related impedance at various stages of discharge and charge. Further, the reversibility of Fe 3O 4 to iron metal (Fe0) conversion observed during discharge was quantitatively assessed ex-situ using X-ray Absorption Spectroscopy (XAS). The Fe 3O 4 composite containing the largest weight fraction of PPy (20 wt%) with added carbon demonstrated reduced irreversible capacity on initial cycles and improved cycling stability over 50 cycles, attributed to decreased reaction with the electrolyte in the presence of PPy. Our study illustrated the beneficial role of PPy addition to Fe 3O 4 based electrodes was not strongly related to improved electrical conductivity, but rather to improved ion transport related to the formation of a more favorable surface electrolyte interphase (SEI).
 [1] ;  [2] ;  [3] ;  [1] ;  [4] ;  [4] ;  [5]
  1. Stony Brook Univ., NY (United States). Dept. of Chemistry
  2. State Univ. of New York, Geneseo, NY (United States). Dept. of Chemistry; Stony Brook Univ., NY (United States). Center for Inclusive Education
  3. Brookhaven National Lab. (BNL), Upton, NY (United States)
  4. Stony Brook Univ., NY (United States). Dept. of Chemistry and Dept. of Materials Science and Chemical Engineering
  5. Stony Brook Univ., NY (United States). Dept. of Chemistry and Dept. of Materials Science and Chemical Engineering; Brookhaven National Lab. (BNL), Upton, NY (United States)
Publication Date:
Report Number(s):
Journal ID: ISSN 0013-4651
Grant/Contract Number:
SC00112704; SC0012673
Accepted Manuscript
Journal Name:
Journal of the Electrochemical Society
Additional Journal Information:
Journal Volume: 164; Journal Issue: 1; Journal ID: ISSN 0013-4651
The Electrochemical Society
Research Org:
Brookhaven National Laboratory (BNL), Upton, NY (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
25 ENERGY STORAGE; electrochemistry; polypyrrole; electrodes; magnetite; galvanostatic; composite electrodes
OSTI Identifier: