Molecular-Scale Interfacial Model for Predicting Electrode Performance in Rechargeable Batteries

It is commonly believed that the formation of a solid-electrolyte interphase (SEI) is the main reason for improved electrode performance in rechargeable batteries. However, herein we present a new interfacial model that may change the thinking about the role of SEI, which has prevailed over the past 2 decades. We show that the varied desolvation behavior of mobile ions, which depends on the solvation structure determined by multiple factors (e.g., cations, solvent, anions, and additives) is a critical factor for electrode stability besides the SEI. This interfacial model can predict the intercalating species in graphite electrodes (i.e., Li+ (de)intercalation or Li+-solvent co-insertion) in different types of electrolytes (e.g., carbonate-, ether-based electrolyte). The generality of our model is further demonstrated by its ability to interpret the variable lithium plating/stripping in different electrolytes. Our model can predict electrode performance through the proposed cation-solvent interactions and desolvation behaviors and then help develop new types of electrolytes for mobile (ion) batteries.