Poly(cyclic carbonate)s embedded in metal-organic frameworks as quasi-solid-state electrolyte

Abstract

To address the challenge of lithium dendrite formation in electrolytes for lithium metal batteries (LMBs), this study investigated the synergistic effect of metal-organic framework (MOF) and polymer. The polymer chain was synthesized within the MOF pores, forming an ordered structure rather than aggregating along the connected pores. This polymer provided sites for lithium-ion conduction within the MOF, facilitating fast movement by enabling Li+ ion hopping between solvent molecules and polymer. Additionally, the solvation environment of Li+ ions was modified through interactions with anions and open metal sites present in the MOF. These effects resulted in improved ionic conductivity and transference number. To verify the impact on the electrochemical reaction within the system predominantly governed by the synthesized PVEC@MIL-101(Cr), a film with a high proportion of MOF was fabricated and applied in battery testing. The reduced pore size and enhanced mechanical stability of PVEC@MIL-101(Cr) inhibited lithium dendrite formation compared to MIL-101 film and glass fiber, which are prone to Li dendrite growth due to their large pore sizes. In conclusion, the collaborative impact between MOF and poly(cyclic carbonate)s led to an enhancement in the transport of Li+ ions. This improvement in lithium-ion conduction demonstrated the potential utility of this system as a quasi-solid-state electrolyte.