2020 Virtual AIChE Annual Meeting
(637f) Theoretical Evidence of Water Serving As a Promoter for the Cathode Reaction in Aprotic Li-O2 Battery
Authors
In this work, the first principles calculations were performed to investigate waterâs promoting role for Li2O2 production on an Au(100) electrode immersed in the explicit dimethoxyethane (DME) electrolyte. Two reaction mechanisms have been evaluated. The first reaction mechanism proposed that water was able to promote the reaction of Li ion and O2 to form Li2O2 via first activating O2 . The second reaction mechanism assumed that water is capable of enhancing the disproportionation reaction from LiO2 dimer to Li2O2. The Ab initio Molecular Dynamics (AIMD) calculations under experimental conditions indicated that the water failed to activate O2 molecule, but succeeded in promoting the disproportionation reaction for Li2O2 formation. The density functional theory (DFT) calculations based on the G4MP2 level of theory further proved the disproportionation reaction to Li2O2 becomes more thermodynamically and kinetically favorable when water exists in the DME electrolyte. This theoretical work advances the fundamental understandings of complex interface reactions on cathode and the efficiency improvement for the Li-O2 battery.