Exploring the use of oligomeric carbonates as porogens and ion-conductors in phase-separated structural electrolytes for Lithium-ion batteries

Phase-separated structural battery electrolytes (SBEs) have the potential to enhance the mechanical stability of the electrolyte while maintaining a high ion conduction. This can be achieved via polymerization-induced phase separation (PIPS), which creates a two-phase system with a liquid electrolyte percolating a mesoporous ther-moset. While previous studies have used commercially available liquid electrolytes, this study investigates the use of novel oligomeric carbonates to enhanced the safety of the SBEs. Increasing the carbonate chain length significantly enhances the thermal stability of the SBEs. Tuning the molecular structure of the liquid electrolyte has a significant effect on the PIPS process and SBE morphology. Using a combination of analyses on a series of wet and dried SBEs, the complex interplay between the phases is interpreted. When an increased pore size is achieved, it leads to a lower MacMullin number (NM). A conductivity of 2 x 10-5 S/cm with a NM=13 could be achieved, while maintaining a thermal stability up to 150 degrees C. The present study demonstrates a versatile approach to tailor this type of electrolyte.

Automated summary

Phase-separated structural battery electrolytes (SBEs), achieved via polymerization-induced phase separation (PIPS), show enhanced mechanical stability and high ion conduction. This study investigates the use of novel oligomeric carbonates to improve the safety of SBEs. Increasing the carbonate chain length improves the thermal stability of the SBEs and tuning the molecular structure of the liquid electrolyte affects the PIPS process and SBE morphology.