(702e) Explaining Gas Evolution Mechanisms in Mg-Ion Batteries with Chemical Reaction Networks
AIChE Annual Meeting
2023
2023 AIChE Annual Meeting
Catalysis and Reaction Engineering Division
Reaction Path Analysis
Thursday, November 9, 2023 - 5:00pm to 5:18pm
Out-of-equilibrium electrochemical reaction mechanisms are notoriously difficult to characterize. However, such reactions are critical for a range of technological applications. For instance, in metal-ion batteries, spontaneous electrolyte degradation controls electrode passivation and battery cycle life. Here, to improve on our ability to elucidate electrochemical reactivity, we combine computational chemical reaction network (CRN) analysis based on density functional theory (DFT) and differential electrochemical mass spectroscopy (DEMS) to study gas evolution from a model Mg-ion battery electrolyte â magnesium bistriflimide (Mg(TFSI)2) dissolved in diglyme (G2). Automated CRN analysis allows for the facile interpretation of DEMS data, revealing H2O, C2H4, and CH3OH as major products of G2 decomposition. These findings are further explained by identifying elementary mechanisms using DFT. While TFSIâ is reactive at Mg electrodes, we find that its decomposition does not meaningfully contribute to gas evolution. The combined theoretical-experimental approach developed here provides a means to elucidate electrolyte reactivity, improving our ability to predict decomposition products and pathways when initially unknown.