Collaborative Research: DMREF: AI-guided Discovery of Sustainable Ion-Conducting Peptide Electrolytes

Non-technical Description: Energy storage technologies such as batteries critically require safe and thermally stable ion-conducting materials. Lithium-ion batteries are pervasive in modern society, but safety concerns have prompted the development of new solid-state ion-conducting materials. To date, nearly all solid polymer ion conductors are comprised of synthetic materials that lack precisely defined structures. In contrast, biological macromolecules such as peptides have precisely defined sequences, allowing for control over three-dimensional molecular structure, such as helical elements. This project aims to understand the role of peptide helices on enhanced ion conduction, focusing on: (1) the ability to arrange ion-conducting groups in controlled ways and (2) the presence of a macrodipole along the backbone that grows with helix length. This project will enable the development of a new class of helical peptide ion conductors for enhanced energy storage applications. A wide range of peptide chemistries will be designed and synthesized using an AI-guided discovery approach to understand the role of chemistry, sequence, helical character, and arrangement of ion-conducting groups on the performance of energy storage materials. A key outcome of this project is to understand how the molecular structure of peptides affects ion transport for the development of next-generation energy storage materials. Technical Description: This project will address key challenges in developing new materials for enhanced ion conduction by efficiently exploring a vast chemical space using a machine learning (ML)-guided approach, together with complementary materials synthesis and characterization methods. The team focuses on developing a new class of helical peptide-based polymers for enhanced ion conduction by controlling the macrodipole inherent to peptide-based helices and the spatial arrangement of ion-conducting motifs away from the backbone. To this end, this project will leverage the ability to control several key properties of peptide electrolytes such as: (1) helicity via introduction of amino acids of opposite chirality; (2) molecular weight via controlled ring-opening polymerizations of cyclic amino-acid monomers; (3) ion conducting motifs and linkages to polymer backbones using non-natural amino acids; (4) monomer sequence via solid-phase peptide synthesis; and (5) alignment of helices via materials processing, e.g., hot-pressing at different temperatures and pressures. PIs and graduate students will engage in outreach activities geared towards hands-on demonstrations of scientific concepts for middle and high school students. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.