In order to realize safer batteries for hybrid/electric vehicles and also for future portable or wearable electronic devices, the development of stable, nonflammable, and efficient lithium ion-electrolytes for high energy density lithium-ion batteries is a high research priority. This project will examine the suitability of a new class of gel electrolyte materials that are composed of molten salts (ionic liquids), lithium ions, and zwitterionic polymers. Expected advantages of these materials include: ultralow volatility, a leak-proof design, and good selectivity for lithium ion transport at room temperature. The outcomes of this work will make an immediate impact in the field of energy storage research and are expected to facilitate the development of safe and effective, nonflammable gel electrolyte-containing lithium ion batteries with high energy densities for real-world applications in the near future. Fundamental knowledge on lithium ion transport in these gel systems will result from this project. In addition, this project will provide support for underrepresented minority students in STEM both at the undergraduate and high school levels to participate in a research experience related to energy storage themes. Broader impact and outreach activities will include providing an annual summer research position in the PI's laboratory and hosting a local high school chemistry class visit and electrolyte activity day. This project is also funded by the CBET Molecular Separations Program, NSF 18-1417.
This project seeks to develop fundamental understanding and create a coherent framework to describe the factors that determine the varying physical and electrochemical characteristics of a novel class of safer electrolytes for future lithium ion batteries: zwitterionic (co)polymer-supported, nonvolatile lithium cation-conducting ionic liquid gel electrolytes. These objectives will be achieved through a comprehensive spectroscopic investigation of various zwitterion-electrolyte ion intermolecular interactions. Gel electrolytes created via in situ free radical polymerization using two promising classes of nonvolatile electrolytes will be examined: lithium-based solvate ionic liquids, as well as conventional lithium salt/ionic liquid solutions. Zwitterion-ion interactions will be probed using NMR, FTIR, and Raman spectroscopies, while ionic conductivity and lithium ion transference number values will be experimentally determined for all gel electrolytes using AC impedance spectroscopy and DC polarization measurements, respectively. Compressive stress-strain testing will be used to determine elastic modulus values of these gel electrolytes. Linear sweep voltammetry, cyclic voltammetry, and galvanostatic charge/discharge cycling will be conducted in order to interrogate gel electrochemical stability and lithium ion battery cell feasibility and performance. One important outcome of this project is linking knowledge of the liquid solution electrochemical properties to the gel version for use as an electrolyte material.
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.
