Presence and Impact of Surface Films formed on Mg in Chloroaluminate Electrolytes.

Program Document · Tue Sep 01 04:00:00 EDT 2015

OSTI ID:1427228

Hahn, Nathan ^[1]; Kotula, Paul G. ^[2]; Wetzel, David J. ^[3]; Malone, Marvin A. ^[3]; Nuzzo, Ralph G. ^[3]; Zavadil, Kevin R. ^[1]

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1. Argonne National Lab. (ANL), Argonne, IL (United States). Joint Center for Energy Storage Research (JCESR); Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
2. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
3. Argonne National Lab. (ANL), Argonne, IL (United States). Joint Center for Energy Storage Research (JCESR); Univ. of Illinois, Urbana-Champaign, IL (United States)

The impact of surface film formation on Mg is explored during electrodeposition and electrodissolution in two high activity, aprotic electrolytes: the all phenyl complex (APC) and the magnesium aluminum chloride complex (MACC). Where past studies have argued such films are benign, results show that interfacial films are responsible for controlling the Mg deposit structure when deposition and dissolution are conducted at the rates required for practical Mg batteries. Chronopotentiometry is shown to provide clear signatures of the impact of interfacial films on deposition and dissolution. The particular combination of cycling punctuated by periods of open circuit equilibration is shown to yield a noticeable decrease in coulombic efficiency over a 50 cycle sequence. High resolution electron imaging shows that cycling results in porosity development and accumulation of electrolyte constituents within the deposit. Reduced coulombic efficiency signaling Mg loss appears related to progressive isolation of a fraction of the deposit. Mg and electrolyte loss must be compensated for in a practical cell through the introduction of excess inventory and resulting in a reduced energy density of the system.

• Research Organization: Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
• DOE Contract Number: AC04-94AL85000
• OSTI ID: 1427228
• Report Number(s): SAND--2015-7663J; 603621
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY