Limitation of Discharge Capacity and Mechanisms of Air-Electrode Deactivation in Silicon–Air Batteries

Authors

  • Dr. Peter Jakes ,

    1. Forschungszentrum Jülich, Institut für Energie- und Klimaforschung, IEK-9, 52452 Jülich (Germany)
    2. Karlsruher Institut für Technologie (KIT), Anorganische Chemie, Materialforschung für neuartige Energiespeichersysteme, Engesserstr. 15, 76131 Karlsruhe (Germany)
    Search for more papers by this author
  • Gil Cohn,

    1. Department of Materials Science and Engineering, Technion-Israel Institute of Technology, Haifa 32000 (Israel)
    Search for more papers by this author
  • Prof. Dr. Yair Ein-Eli,

    1. Department of Materials Science and Engineering, Technion-Israel Institute of Technology, Haifa 32000 (Israel)
    Search for more papers by this author
  • Dr. Frieder Scheiba,

    1. Karlsruher Institut für Technologie (KIT), Institut für Angewandte Materialien (IAM-ESS), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany), Fax: (+49) 721-60848142
    Search for more papers by this author
  • Prof. Dr. Helmut Ehrenberg,

    1. Karlsruher Institut für Technologie (KIT), Institut für Angewandte Materialien (IAM-ESS), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany), Fax: (+49) 721-60848142
    Search for more papers by this author
  • Dr. Rüdiger-A. Eichel 

    Corresponding author
    1. Karlsruher Institut für Technologie (KIT), Institut für Angewandte Materialien (IAM-ESS), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany), Fax: (+49) 721-60848142
    2. Forschungszentrum Jülich, Institut für Energie- und Klimaforschung, IEK-9, 52452 Jülich (Germany)
    • Karlsruher Institut für Technologie (KIT), Institut für Angewandte Materialien (IAM-ESS), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany), Fax: (+49) 721-60848142
    Search for more papers by this author

Abstract

The electrocatalytical process at the air cathode in novel silicon–air batteries using the room-temperature ionic liquid hydrophilic 1-ethyl-3-methylimidazolium oligofluorohydrogenate [EMI2.3 HFF] as electrolyte and highly doped silicon wafers as anodes is investigated by electrochemical means, X-ray photoelectron spectroscopy (XPS), and electron paramagnetic resonance (EPR) spectroscopy. The results obtained by XPS and EPR provide a model to describe the limited discharge capacity by means of a mechanism of air-electrode deactivation. In that respect, upon discharge the silicon-air battery′s cathode is not only blocked by silicon oxide reduction products, but also experiences a major modification in the MnO2 catalyst nature. The proposed modification of the MnO2 catalyst by means of a MnF2 surface layer greatly impacts the Si–air performance and describes a mechanism relevant for other metal–air batteries, such as the lithium–air. Moreover, the ability for this deactivation layer to form is greatly impacted by water in the electrolyte.

Ancillary