Solvation and Desolvation Phenomenon and in-Situ NMR Studies on Stripping/Plating of Magnesium Metal in Magnesium Batteries

Multivalent batteries are promising technologies that can potentially outperform lithium ion batteries in term of energy density, power density and unit cost.¹ Among which magnesium batteries have attracted much attention over the last a few years. However, scientific challenges continue primarily due to the lack of understanding of the intercalation mechanism of multivalent ions.² Our recent study is devoted to the understanding of the solvation and desolvation effect with ¹H and ²D solid-state NMR spectroscopy by probing the movement of the water molecules and  solvent molecules in the system (Bis(trifluoromethan sulfonyl)Imide dissolved in diglyme based magnesium batteries) at various charge states. It is suggested that the water and diglyme molecules play a crucial role in facilitating the intercalation of the magnesium ions in the cathode lattice upon charging and discharging. ³

In addition, the effective stripping and plating effect on the magnesium metal is also investigated. By taking advantage of in situ NMR spectroscopy, we investigate metal vs metal pseudo cells while the cells are polarized. No significant changes in the NMR spectra  between the pristine and cycled pseudo cell for Grignard electrolytes, which is in agreements with reversible smooth stripping and plating.

1              D. Aurbach, Z. Lu, A. Schechter, Y. Gofer, H. Gizbar, R. Turgeman, Y. Cohen, M. Moshkovich, E. Levi, Nature 2000, 407, 724-727 10.1038/35037553.

2              H. D. Yoo, I. Shterenberg, Y. Gofer, G. Gershinsky, N. Pour, D. Aurbach, Energy & Environmental Science 2013, 6, 2265-2279 10.1039/c3ee40871j.

3              S. H. Lapidus, N. N. Rajput, X. Qu, K. W. Chapman, K. A. Persson, P. J. Chupas, Physical Chemistry Chemical Physics 2014, 16, 21941-21945 10.1039/c4cp03015j.