Development of Multivalent Electrolytes with a Wide Electrochemical Window and Their Applications

Multivalent (MV) ion batteries have been under intense scrutiny because the modeling effort predicted that a high Mg2+ diffusion mobility in spinel cathodes and a higher specific energy density can be achieved. Recently new cathodes have been tested against Mg, with novel cathodes such as layered oxides MoO2.8F0.2,1 MgCr2-xVxO4,2 and conversion-type cathodes.3 Previously chloride containing electrolytes4 were dominant in multivalent ion batteries because of their facile deposition and high Coulombic efficiency towards the anode. However, the corrosion issue of Cl- limits their application. Here we report the development of chloride-free multivalent salts with a weakly coordinating anion that shows exceptional electrochemical properties. Moreover, the passivation-free properties of these anions make them efficient in assessing the Mg2+ mobility inside a solid solution electrode. Further development on other multivalent cations will also be demonstrated. Together with cathodes, these electrolyte developments would pave the way for a holistic approach towards high energy density multivalent batteries. References T. Incorvati, L. F. Wan, B. Key, D. Zhou, C. Liao, L. Fuoco, M. Holland, H. Wang, D. Prendergast, K. R. Poeppelmeier, Chemistry of Materials 2015, 28, 17-20. J. Kwon, K.-C. Lau, H. Park, Y. A. Wu, K. L. Hawthorne, H. Li, S. Kim, I. L. Bolotin, T. T. Fister, P. Zapol, R. F. Klie, J. Cabana, C. Liao, S. H. Lapidus, B. Key, J. T. Vaughey, Chemistry of Materials 2019. DOI:10.1021/acs.chemmater.9b04206 Pan, J. Huang, Z. Feng, L. Zeng, M. He, L. Zhang, J. T. Vaughey, M. J. Bedzyk, P. Fenter, Z. Zhang, C. Liao, Advanced Energy Materials 2016, 6. Pan, J. Huang, N. Sa, S. M. Brombosz, J. T. Vaughey, L. Zhang, A. K. Burrell, Z. Zhang, C. Liao, * Journal of The Electrochemical Society 2016, 163, A1672-A1677. -C. Lau, T. J. Seguin, E. V. Carino, N. T. Hahn, J. G. Connell, B. J. Ingram, K. A. Persson, K. R. Zavadil, C. Liao, * J. Electrochem. Soc. 2019, 166, A1510-A1519.