Local Atomic and Electronic Structure's Influence on Migration Along Li and Mg Surfaces

Dendrite formation on Li metal anodes leads to reduced Coulombic efficiency, poor cycling stability and short-circuiting, and prevents commercialization of high energy density rechargeable Li metal batteries. The migration energy barrier for transport along the metal surface can describe the tendency of the surface to form dendrites. Density functional theory calculations of the migration energy barrier show inherent differences in transport properties between Li and Mg[1], which may explain the higher propensity of Li to form dendrites compared to Mg[2]. We use density functional theory to show that differences in the atomic and electronic structure of the Li and Mg surface lead to different migration energy barriers[3]. The atomic and electronic surface structure of Li and Mg are in turn affected by the bulk crystal structure, the atomic and electronic structure of the substrate, and surface impurities. We investigate how and why these factors impact the migration energy barrier to shed light on the mechanisms of dendrite formation on the metal anodes. Thus, we may guide the development of dendrite-free metal anodes for battery applications. References: 1. M. Jäckle, A. Groß, J. Chem. Phys. 141 (2014) 174710 2. M. Matsui, K. Takahasi, K. Sakamoto, A. Hirano, Y. Takeda, O. Yamamoto, N. Imanishi, Dalton trans. 43 (2014) 1019 3. I. T. Roee, S. M. Selbach, S. K. Schnell, J. Phys. Chem. Lett. 11 (2020) 2891-2895