"Design of Polymeric Zwitterionic Solid Electrolytes with Superionic Lithium Transport"

Seamus D. Jones¹, Shivani P. Wadgaonkar¹, Pratyusha Das^1,4, Craig J. Hawker^2,3, Raphaele J. Clement^3,4, Glenn H. Fredrickson^1,3,4, Rachel A. Segalman^1,3,4

¹Department of Chemical Engineering, University of California, Santa Barbara, CA / ²Department of Chemistry, University of California, Santa Barbara, CA / ³Department of Materials, University of California, Santa Barbara, CA / ⁴Materials Research Laboratory, University of California, Santa Barbara, CA

Solid polymeric electrolytes (SPEs) can help mitigate instabilities at electrolyte–electrode interfaces and safety concerns associated with energy-dense lithium metal anodes; however, they are limited by low conductivity owing to sluggish polymer segmental dynamics. In fact, it remains challenging to attain SPEs with both high ionic conductivity and lithium selectivity. With the aim to decouple ion transport from polymer segmental dynamics, we demonstrate the use of zwitterionic SPEs that self-assemble into superionically conductive domains with labile ion–ion interactions. Interestingly, such semicrystalline polymer electrolytes when tailored with varying ion sizes exhibit excellent Li­⁺ conductivity (1.6 mS/cm) and selectivity (t₊ ≈ 0.6–0.8). This new design paradigm for SPEs allows for simultaneous optimization of previously orthogonal properties, including conductivity, Li selectivity, mechanics, and processability. Moving forward, our work focuses on the design of novel polymer electrolytes by varying their backbone and pendant architectures to study their structure-property relationships.