Using data-science approaches to identify novel lithium conducting polymers with enhanced ionic conductivity

Solid polymer electrolytes have yet to achieve a conductivity of 1 mS/cm near room temperature required for many applications. We will present our efforts to construct a database for temperature-dependent ionic conductivity in single-ion conductors (SICs) by using experimental results from the literature. Analysis of the temperature-dependent ionic conductivities in lithium conducting SICs reveals that achieving an ionic conductivity of 1 mS/cm at room temperature requires the effective lithium transport energy barrier to be less than 20 kJ/mol. Currently, no such polymer electrolyte has been reported. To design the next-generation lithium conducting SICs, we first identified several boron-based anions with delocalized charges, which requires further refinements to achieve the targeted energy barriers. We then used density functional theory (DFT) based calculations and statistical models to connect the chemical structures, binding energy of cation-anion pairs, and the energy barriers for lithium transport in boron-based SICs. Not only have we identified correlations between the binding energy and the energy barriers, but we also propose new boron-based SICs by using the correlations. This approach, which combines reported data, theoretical analysis and calculation, and a physics-based interpretation of the energy barriers, is capable of identifying potential new anions with high ionic conductivities, thereby expediting the development of novel superionic SICs.