Data-Driven Discovery of Non-Aqueous Proton Conductors for Polymer Electrolytes Using Density Functional Theory

Polymer electrolytes are crucial components in energy storage and conversion devices, including fuel cells and lithium-ion batteries. Their advantages over liquid and ceramic alternatives include high electrochemical stability, mechanical flexibility, and superior interface stability. However, their dependence on water as a proton conductor limits operating temperatures to below water's boiling point, constraining the performance of polymer electrolyte membrane fuel cells. This study investigates amphoteric molecules—capable of both proton acceptance and donation—as potential non-aqueous proton conductors using density functional theory calculations. We evaluate proton affinity energy as a proxy for proton transfer barriers and analyze how various molecular features influence proton mobility. These features include electron-donating and withdrawing groups, dipole moments, and structural fingerprints. Our computational analysis reveals structure-property relationships that identify promising molecules with water-like proton affinities. By establishing these fundamental relationships, our research lays the groundwork for data-driven approaches to accelerate the discovery of high-temperature, water-free polymer electrolytes.
This work was supported by the Fast and Cooperative Ion Transport in Polymer-Based Materials (FaCT), EFRC funded by the U.S. DOE, Office of Science, BES at ORNL. This work used resources of NERSC, which is supported by the DOE Office of Science under Contract no. DE-AC02-05CH11231.