Tuning Ionic Conductivity and Mechanical Properties of Network SPEs

Solid polymer electrolytes (SPEs) are regarded as a promising solution to next-generation lithium metal batteries. However, the trade-off between ionic conductivity and mechanical properties remains a challenging obstacle. In this poster, we display how molecular engineering polymer networks can tune such properties for LMB applications. We designed, synthesized and characterized different types of PEO-based networks including star-type single networks, comb-type single networks and interpenetrating networks (IPNs) with poly(carbonate) or poly(ionic liquid) chemistry. Our results showed that the network mesh size plays a significant role in tuning ion diffusion as well as mechanical properties. Salt concentration and polymer backbone chemistry were also established to have an impact on ionic diffusion. Compared with poly(ether) systems, the incorporation of poly(carbonate) can help liberate cations and thus improve the cation transport efficiency. Additionally, the introduction of free mobile polymers or mono-functionalized dangling chains can facilitate ionic conduction. Moreover, the comb-type network structure has enhanced mechanical properties compared to the star-type network.