Theoretical study of processes on the solid electrolyte interface of rechargeable magnesium batteriesKopač Lautar, Anja (Avtor) Rejec, Tomaž (Mentor) Doublet, Marie-Liesse (Komentor) interfacesdouble layersurface sciencebatteriesmagnesium batterieselectrochemistryThe research of battery materials is becoming an increasingly important scientific field due to the growing demand for the electric energy. Magnesium batteries represent one of the promising multivalent battery architectures. To optimize the Mg battery for commercial use, a potential dependent interfacial processes should be understood. Yet, due to great complexity of the interface, there is a lack of theoretical approaches that would enable facing this challenge. A computationally affordable, fully unparameterized, and widely applicable theoretical methodology based on density functional theory and grand canonical approach is extended to investigate the electrochemical stability of Mg-metal/electrolyte interfaces, and to predict their thermodynamic behaviour. The calculated Mg$^{2+}$/Mg$^{0}$ redox potential differs by less than 3\% from the experimental value, demonstrating that the methodology provides physically meaningful and reliable results. The methodology is used to study two different Mg electrolytes, based on ethylene carbonate (EC) and dimethylether (DME) solvents. Experiments have shown that the Mg battery fails with the EC electrolyte, while it works fairly well with the DME electrolyte. Our results successfully elucidate atomistic mechanisms that explain the experimental observations. Moreover, our theoretical insights provides valuable guidelines for designing electrolytes with favourable properties. To broaden the theoretical understanding from atomistic to meso-scale, the dependence of morphology evolution on surface orientation is investigated. We found that the surface with the highest area fraction is not necessarily the one with the lowest surface energy, which is usually the only one considered in literature. Morphology evolution should thus be studied on all commonly present surface orientations. Our results show that diffusion of Mg atoms on the Mg anode is slow on some commonly present Mg surface orientations, indicating that Mg could exhibit uneven deposition.20192019-10-21 15:28:13Doktorsko delo/naloga112049sl