Atomic-Level Mechanistic Insights into Carbonate Electrolyte Degradation on High-Voltage LiCoO₂ Cathodes^†

Batteries power numerous technologies, yet higher energy density demands push lithium cobalt oxide (LiCoO₂ referred as LCO) cathodes to higher voltages, triggering unwanted chemical reactions. In this work, we investigate how carbonate-based electrolytes degrade on deeply delithiated LCO surfaces via extensive reactive molecular dynamics simulations. These simulations unveil the formation of characteristic gas products and unstable surface species, which can undermine the cathode structure and reduce battery performance. By examining different solvent compositions, the simulations reveal that partial fluorination reduces oxidative degradation and gas evolution, thus offering a route to improve interface stability. Overall, this study provides an atomic-level perspective on preventing unwanted reactions and guiding the design of safer and more robust battery systems for high-voltage applications.