(718h) Atomistic Modeling of Solvent Decomposition in Magnesium Batteries

The lithium-ion (Li-ion) battery has revolutionized the consumer electronics industry in the past two decades, achieving moderate battery lifetimes and higher energy storage densities. However, we have begun to reach the limits to improvements in Li-ion batteries. Further, in order to reach the energy demands posed by the transportation industry, batteries that possess energy densities much larger than current state-of-the-art Li-ion technologies are highly desirable. This research investigates one ‘beyond Li-ion’ battery technology that boasts a theoretical energy density more than five times larger than Li-ion batteries: metallic magnesium (Mg) batteries. We used density functional theory to probe atomistic interactions on the metallic Mg anode surface. Specifically, we identified likely reactions occurring between the anode surface and the battery solvent. The composition of the model Mg anode surface was modified to mimic realistic electrode surfaces. We found that solvent decomposition products and reaction energies were highly dependent on the model anode surface composition, with the pristine Mg anode displaying a greater tendency for solvent decomposition. This study provides a more complete picture of the atomic-scale factors governing the successful implementation of metallic Mg anodes for beyond Li-ion batteries.