Alternatives for Magnesium Metal Anodes? Intercalation Materials As Negative Electrodes for Rechargeable Magnesium-Ion Batteries

Abstract

The unabated demand of cost-effective and high performance battery systems compells research groups to look for further improvements of energy storage systems around the world. Lithium-ion batteries seem to be an appropriate solution for this energy issue, but on the other hand extraordinary breakthroughs within the next years are not to be anticipated. Furthermore, lithium-ion batteries still suffer from serious safety concerns. Considering properties such as a rather low reduction potential (-2.36 V vs. SHE), high specific capacity (3380 mAh/cc), low equivalent weight and moreover, sufficient safety due to a non-dendritic metal deposition, magnesium-ion batteries appear to be competitive to lithium-ion batteries [1]. Since organic, aprotic electrolyte systems create a passivation layer on the Mg metal surface preventing a reversible Mg-deposition and dissolution, corrosive electrolytes such as Grignard compounds have to be used [2]. However, research focuses on the development of Mg-battery systems with an operational voltage of 3V Grignard electrolytes do not provide. A strategy to achieve the ambitious 3V goal is the development of intercalation/insertion compounds such as tin or graphite and replacement of corrosive electrolytes by organic ones [3]. From literature it is well known that the Mg-intercalation into graphite is impossible showing even solvated intercalation [4, 5]. However, in this contribution we want to shed light on the intercalation behavior of Mg into graphite with a broad range of electrochemical and spectroscopical analysis methods showing a non destructive and reversible magnesiation and de-magnesiation of a common graphite electrode with organic, aprotic electrolytes (cf. figure 1, figure 2 and figure 3). References: [1] P. Saha, M.K. Datta, O.I. Velikokhatnyi, A. Manivannan, D. Alman, P.N. Kumta. Progress in Materials Science 66, 2014, 1-86. [2] Z. Lu, A. Schechter, M. Moshkovich, D. Aurbach. Journal of Electroanalytical Chemistry, 1999, 203–217. [3] N. Singh, T.S. Arthur, C. Ling, M. Matsui, F. Mizuno. ChemComm, 2012. [4] M. Kawaguchi, A. Kurasaki. Chem. Commun., 2012, 48, 6897–6899. [5] Y. Maeda, Ph. Touzain. Electrochimica Acta, 1988, 1493-1497. Figure 1