On enhancing the Li-ion conductivity of quasi-solid-state electrolytes by suppressing the flexibility of zeolitic imidazolate framework-8 via a mixed ligand strategy

P Utpalla; J Mor; S K Sharma

doi:10.1039/d2cp05811a

On enhancing the Li-ion conductivity of quasi-solid-state electrolytes by suppressing the flexibility of zeolitic imidazolate framework-8 via a mixed ligand strategy

Phys Chem Chem Phys. 2023 Feb 1;25(5):3959-3968. doi: 10.1039/d2cp05811a.

Authors

P Utpalla^{1

2}, J Mor¹, S K Sharma^{1

2}

Affiliations

¹ Radiochemistry Division, Bhabha Atomic Research Centre, Mumbai 400 085, India. skumars@barc.gov.in.
² Homi Bhabha National Institute, Mumbai 400 094, India.

PMID: 36648501
DOI: 10.1039/d2cp05811a

Abstract

Zeolitic imidazole frameworks (ZIFs) have emerged as potential conductive materials for Li ion-transport in polymer solid state electrolytes. However, developing ZIFs with high Li ionic conductivity is rather limited due to their flexible frameworks allowing dual ion conduction. Herein, we have used a mixed ligand strategy for fine-tuning the aperture and enhancing the rigidity of ZIF-8, which restricts the passage of large size anions. Poly(ethylene oxide)-based quasi-solid state electrolytes utilizing mixed ligand ZIF-7-8 frameworks as passive fillers show a continuous enhancement in Li ion-conductivity exclusively attributed to modifications in the flexibility and pore architecture of ZIF-8 as confirmed through broadband dielectric spectroscopy and positron annihilation spectroscopy. This study shows that polymer segmental relaxation and conductivity relaxation processes are decoupled in these electrolytes. Consequently, our proposed approach provides a new strategy for manufacturing a polymer-based electrolyte with enhanced ionic conductivity.