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Title: Passivation dynamics in the anisotropic deposition and stripping of bulk magnesium electrodes during electrochemical cycling

Rechargeable magnesium (Mg) batteries show promise for use as a next generation technology for high-density energy storage, though little is known about the Mg anode solid electrolyte interphase and its implications for the performance and durability of a Mg-based battery. We explore in this report passivation effects engendered during the electrochemical cycling of a bulk Mg anode, characterizing their influences during metal deposition and dissolution in a simple, nonaqueous, Grignard electrolyte solution (ethylmagnesium bromide, EtMgBr, in tetrahydrofuran). Scanning electron microscopy images of Mg foil working electrodes after electrochemical polarization to dissolution potentials show the formation of corrosion pits. The pit densities so evidenced are markedly potential-dependent. When the Mg working electrode is cycled both potentiostatically and galvanostatically in EtMgBr these pits, formed due to passive layer breakdown, act as the foci for subsequent electrochemical activity. Detailed microscopy, diffraction, and spectroscopic data show that further passivation and corrosion results in the anisotropic stripping of the Mg {0001} plane, leaving thin oxide-comprising passivated side wall structures that demark the {0001} fiber texture of the etched Mg grains. Upon long-term cycling, oxide side walls formed due to the pronounced crystallographic anisotropy of the anodic stripping processes, leading to complex overlay anisotropic, columnar structures,more » exceeding 50 μm in height. Finally, the passive responses mediating the growth of these structures appear to be an intrinsic feature of the electrochemical growth and dissolution of Mg using this electrolyte.« less
 [1] ;  [1] ;  [1] ;  [1] ;  [2] ;  [3] ;  [2] ;  [1] ;  [3] ;  [1] ;  [1]
  1. Univ. of Illinois, Urbana, IL (United States)
  2. Univ. of Bielefeld, Bielefeld (Germany)
  3. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Publication Date:
OSTI Identifier:
Report Number(s):
Journal ID: ISSN 1944-8244; 590456
Grant/Contract Number:
Accepted Manuscript
Journal Name:
ACS Applied Materials and Interfaces
Additional Journal Information:
Journal Volume: 7; Journal Issue: 33; Journal ID: ISSN 1944-8244
American Chemical Society
Research Org:
Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; 36 MATERIALS SCIENCE rechargeable magnesium battery; magnesium anode; passivation; corrosion; columnar growth