(167e) Ion Conductive High Li+ Transference Number Polymer Composites for Solid-State Batteries

Finding a suitable replacement for liquid electrolytes in Lithium-ion batteries has been the focus of much work in the last few years due to the desire for a safer product and for an electrolyte that is stable against a solid lithium anode. Composite-solid electrolytes (CSEs) are considered a promising class of materials to replace liquid electrolytes because of their ability to combine the desirable conductivity of ceramics with the robust mechanical properties of polymers. While substantial work has been done in testing the performance of different combinations of ceramics and polymers, there has been far less investigation into the underlying transport mechanism in these CSEs.

This work aims to examine a CSE system consisting of the garnet-type LiLaZrO2 (LLZO) and the single-ion conductor poly(lithium bistrifluorosulfonylimide methacrylate) (Li-PMTFSI), with the goal to identify transport mechanisms of the system in addition to quantifying critical electrochemical properties. The LLZO provides a conductive material that is kinetically stable against a lithium anode, while the Li-PMTFSI gives a polymer phase that ensures a high transference number, a feature that may improve interfacial impedance between the polymer and ceramic. The Li+ ion pathway is examined using a combination of electrochemical and solid-state nuclear magnetic resonance (NMR) techniques to determine how ion transport changes with parameters like ceramic content. This understanding is coupled with knowledge of the ion transport mechanism to design a CSE with optimal conductivity, thin-film processability, and low electrode interfacial impedance.