Interfacial atomistic reactive mechanisms of magnesium batteries

CL Gao and WY Zhao and YQ Gong and YL Chen and LM Cai and XW Yang and MH Yang, ENERGY STORAGE MATERIALS, 80, 104361 (2025).

DOI: 10.1016/j.ensm.2025.104361

Magnesium batteries are emerging as a promising rechargeable technology due to the high theoretical capacity and enhanced safety features. However, their practical applications are still limited by issues of instability and low operating voltages. A key challenge is the instability of electrolytes under high-voltage conditions, which hampers the advancement of Mg battery technologies. Additionally, the mechanisms underlying electrolyte decomposition are not well understood. In our study, we first constructed fully atomistic Mg battery model to investigate the decomposition rates and by-products of dimethoxyethane (DME) in Mg symmetric cells under varying voltage conditions. Our results indicate that DME undergoes a high rate of decomposition, producing gases such as CH4, C2H4, C2H6, as well as alcohol-based by- products. The decomposition rate increases with voltage, and hydroxyl (OH) groups further accelerate this process. Comparative analysis with diglyme (DGM) and tetrahydrofuran (THF) revealed significantly lower decomposition rates for DGM and THF. These findings provide critical insights into the decomposition mechanisms of Mg battery electrolytes, and suggest future research directions for enhancing Mg battery cycling performance.

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