Multiscale Simulation of Carbonate-Based Electrolytes for Li-Ion Battery

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Organic electrodes have been extensively studied for their application as cathode materials for Li-ion battery due to their relatively inexpensive synthesis, earth-abundant precursors, and their high-rate capabilities. In our previous studies, we developed hybrid machine learning-density functional theory protocols to predict and analyze the redox potentials for novel organic moieties. Although the prediction of the electrochemical activity is critical for the design of high energy density cathodes, one of the most detrimental challenges facing the practical application of organic electrode materials is their dissolution by liquid electrolytes. Therefore, it is necessary to investigate several avenues to curb this undesirable dissolution by the electrolyte. In this fundamental study, we investigate novel carbonate-based solid-polymer electrolytes (SPE) using MD simulations and compare their performance to their conventional liquid carbonate electrolyte counterparts. Specifically, we characterize how the nanophase morphology of the amorphous polycarbonate systems is affected by modulating the composition of the carbonate side chains, while comparing them with their liquid electrolyte counterparts such as dimethyl carbonate and ethylene carbonate. Moreover, our study will elucidate how the morphology and thermodynamic properties, such as glass transition temperature, are affected by using aliphatic vs aromatic carbonate side chains, mixing of the side chain types, as well as by adjusting the length of the spacer carbon chain between the carbonate groups and the main chain. Therefore, this investigation can provide valuable insight regarding the optimal polymeric composition and mixture to achieve a morphology that is desirable for enhanced ion transport, while also inhibiting the disintegration of the organic cathode by the electrolyte.