Novel Solid Electrolytes Based on Polymeric Ionic Liquids
Abstract
High energy density energy storage devices are required to lighten the load borne by soldiers in the field. Multivalent batteries, such as those based on Mg(II), Zn(II), or Al(III), improve volumetric energy density, reduce cost, and enhance device safety over lithium-ion batteries. However, advances are required to develop electrolytes that enable stable cycling for rechargeable systems. We propose a design strategy for polymer electrolytes with enhanced mechanical and electrochemical stability over organic liquids based on polymers with pendant ligands. The pendant ligands promote metal salt dissociation with mobility controlled by the kinetics of the metal-ligand binding, combined with the segmental mobility of the polymer backbone. Preliminary results indicate that because the metal cation forms multi-ligand coordination bonds, these bonds act as transient cross-links dramatically improving the modulus of the materials without hindering ionic conductivity. This proposal incorporates an integrated strategy of polymer backbone and ligand design with detailed studies of ionic mobility, conductivity, and transport number. The goal of this research program is to gain a deep understanding of the factors that control multivalent cation conduction in polymer electrolytes by establishing a structure-activity-relationship (SAR), and then exploiting those insights to produce polymer electrolytes with unprecedented levels of ion conduction. This will be achieved by combining the expertise of a polymer electrolyte expert, with state-of-the-art polymer synthesis capabilities, and synthetic and analytical expertise of an inorganic chemist, with a deep knowledge of cation-ligand interactions. Polymer electrolyte performance will be evaluated by electrochemical impedance spectroscopy and solid-state, pulsed-field gradient NMR experiments, along with general characterization of polymer dynamics by rheometry and calorimetry. Design rules for enhancing cation transport will be developed through iterative measurement, synthesis, and design of polymers and the ligating groups in these polymers. The data obtained will be part of a design-build-learn cycle, where ligand design, polymer design, and performance insights feed into each other in an effort to optimize the properties of the polymer electrolyzes. The materials produced in this effort will result in a deeper understanding of ion conduction in polymer electrolytes, as well as superior polymer electrolytes that result in higher ion battery performance.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jan 04, 2023
- Source ID
- W911NF2310015
Entities
People
- Rachel A. Segalman
Organizations
- Army Contracting Command
- United States Army
- University of California, Santa Barbara