Studies of New Rechargeable Mg-Ion Battery Using Boron-Hydrogen Based Electrolytes

Abstract

Mg-ion battery is one of the most promising candidates for a post Li-ion battery due to its high capacity, improved safety and potentially reduced cost. However, since the metallic Mg-anode is prone to passivation by electrolytes, we need to carefully use appropriate electrolytes which have high stability to the Mg metal. For example, common anions such as ClO4 -, BF4 - or TFSI- decompose on the Mg surface resulting in a highly resistive layer that partially or fully blocks Mg-ion transport. Although organo and chloride based reagents were found to be compatible with Mg metal, they still have severe issues such as highly corrosive nature and low Mg-ion transference number.1) We have been pioneering the development of a new class of electrolytes based on a novel design strategy and offering halogen free and non-corrosive boron-hydrogen salts, which can also improve the transport and solubility properties.2) Another serious challenge facing Mg battery technologies is the limited choice of cathode materials due to the difficulty to reversibly intercalate divalent Mg-ion in host structures analogues to those used in Li-ion batteries such as transition metal oxides.3)Therefore, we have been studying alternative cathode chemistries beyond the intercalation types. The inertness and stability of the MMC electrolyte allow us to examine these new cathodes where fast and stable charge/discharge cycles can be performed with a relatively fine coulombic efficiency. In this presentation, we will unveil these new results and also show detailed mechanisms towards understanding the battery performance. [1] J. Wook Choi, D. Aurbach, doi:10.1038/natrevmats.2016.13, Nature Reviews Materials, 2016 [2] a) R. Mohtadi, M. Matsui, T. S. Arthur, S.-J. Hwang, Angew. Chem. Int. Ed. 2012, 51, 9780 –9783; b) T. J. Carter, R. Mohtadi, T. S. Arthur, F. Mizuno, R. Zhang, S. Shirai, J. W. Kampf, Angew. Chem. Int. Ed. 2014, 53, 3173-3177; c) O. Tutusaus, R. Mohtadi, ChemElectroChem. 2015, 1, 51-57 d) O. Tutusaus, R. Mohtadi, T. Arthur. F. Mizuno, Angew. Chem. Int. Ed. 2015, 27, 8011-8015 [3] a) H. D. Yoo, I. Shterenberg, Y. Gofer, G. Gershinsky, N. Pour, D. Aurbach, Energy Environ. Sci. 2013, 6, 2265-2279; b) R. Mohtadi, F. Mizuno Beilstein J. Nanotechnol. 2014, 5, 1291–1311