(684i) Plating/Stripping Performance of Different Substrates in Magnesium Borohydride Solution

Saraidaridis, J. D., University of Michigan
Vardar, G., University of Michigan
Sleightholme, A. E. S., University of Michigan
Monroe, C. W., University of Michigan
Siegel, D. J., University of Michigan

Plating/Stripping Performance of Different
Substrates in Magnesium Borohydride Solution

James D. Saraidaridis1, Gulin Vardar2, Alice E. S. Sleightholme1,
Donald J. Siegel3, Charles W. Monroe1

of Chemical Engineering, University of Michigan

of Materials Science and Engineering, University of Michigan

of Mechanical Engineering, University of Michigan

2300 Hayward St

Ann Arbor, MI 48109

High theoretical energy
densities have attracted many researchers to metal-oxygen batteries in search of
post-Li-ion technologies. The Mg-O2 chemistry offers higher
theoretical volumetric energy densities than popular Li-O2 chemistry
[1][2], which is important in constrained-volume applications like electric
vehicles.  A magnesium system has
large potentials associated with oxygen reactions forming MgO
(2.95V vs. Mg/Mg2+) and MgO2 (2.91V vs. Mg/Mg2+).
The largest hurdle to demonstrating rechargeable Mg-O2 batteries
remains the development of suitable electrolytes that allow plating/stripping
of Mg metal, prevent side reactions at potentials dictated by the plating and
oxygen reactions, and are chemically inert to O2.

Researchers recently
demonstrated the use of magnesium borohydride (Mg(BH4)2) in
DME as an electrolyte in a Mg-ion battery [3]. We sought to explore the
performance of this electrolyte with various electrode substrates. The use of
microelectrodes and a consistent dimensionless scan rate allows a fair
comparison between electrodes of different material and radii. While no
substrate was found stable across the relevant potentials for Mg-O2
reaction, there is a clearly demonstrated difference in the substrate activity
for the Mg plating/stripping reaction.

[1] C. Zu,
H. Li. (2011). Energy & Environmental Science. 4: 2614-2624.

K. Abraham, Z. Jiang. J. Electrochem. Soc. 143: 1-5.

M. Matsui, T. Arthur, S. Hwang. Angewandte Chemie. 51: 9780-9783.