Modeling Degradation Mechanisms in Magnesium Batteries with Electronic Structure Calculations

With ever-increasing global energy demands, emphasis on the development of renewable sources of energy continues to increase. Of particular interest are energy storage technologies that include multi-valent systems based on magnesium, rather than monovalent lithium. These systems promise energy densities which could surpass state-of-the art Li-ion batteries. One potential drawback of this technology, however, is the degradation of the electrolyte due to reactions with battery electrodes. To investigate this issue, electronic structure calculations are employed to map-out degradation mechanisms for a range of common electrolytic solutions with a magnesium anode. Classical Monte Carlo techniques coupled with density functional theory were used to identify and classify the most likely sites for adsorption of electrolyte components on low-energy magnesium surfaces. Further, energy landscapes for the various degradation mechanisms were determined. From these results, we postulate the most likely degradation pathways, identify the factors that control electrolyte stability, and ultimately pinpoint promising electrolyte compositions.