Single-Ion Conducting Polymer Blend Electrolytes for Lithium Batteries

About This Grant

This project will improve the performance of lithium batteries by advancing understanding of polymer electrolytes. A series of experiments will be conducted to formulate polymer electrolytes and discover the key characteristics that determine their suitability in lithium batteries. The project will generate innovative electrolyte materials that can improve ionic conductivity and suppress lithium dendrite formation, enabling safer, longer-lasting battery operation. Outcomes of the research can be extended to other battery chemistries and energy storage formats. The project will support training of graduate and undergraduate students who will be prepared to join the STEM workforce. Local high school students will be recruited to participate in a summer workshop on electrochemistry at FSU and possibly continue undergraduate research at the National High Magnetic Field Laboratory. Improvement in the safety, reliability, and energy density of batteries for electric vehicles will have a significant impact on sustainable energy technologies. This project focuses on polymer blend electrolytes (PBEs) containing a charged polymer (polyanion) and a polar polymer (polysolvent). The charged polymer yields single-ion conduction of lithium ions by immobilizing anions on a macromolecule. The polar polymer facilitates cation dissociation and conduction. This approach builds on prior work that demonstrated the simplicity of formulating PBEs of different chemical combinations and different compositions. The team’s prior experiments agree with theoretical predictions that ion presence and correlation strength have a major impact on PBE phase behavior. However, it is not clear what material properties are most important in determining ion correlation strength. The first aim of the project will resolve this question. An array of material properties, including dielectric constant, functional group spacing, and ion chemistry will be investigated. The second aim will examine ion and polymer dynamics in homogeneous PBEs and hybrid electrolytes comprising PBEs and a sulfide-based inorganic electrolyte. The third aim will experimentally evaluate interfacial behavior, voltage stability, battery cycling, and dendrite formation with 2–3 top-performing PBEs and their hybrid analogues. Interfacial stability will be achieved through a combination of intelligent design of polysolvent chemistry and matching of transference number, which will translate to higher achievable battery cycling rates and slower lithium metal dendrite growth rates, both to be measured. The coordinated effort to develop mechanistic insight into PBE ionic conductivity will study combinations of novel, judiciously synthesized new materials. 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.