Engineering zirconium organic gels for fast Li+ conduction

Abstract

Metal-organic gels (MOGs) are emerging as promising ion‐conductive materials due to their tunable porosity, structural flexibility, and high defect density. In this study, the ionic conduction properties of Zr-MOG and its LiCl-doped derivatives under anhydrous conditions have been investigated. Structural characterization via N₂ physisorption reveals that Li ⁺ doping reduces long‐range crystallinity and increases specific surface area, thereby facilitating the formation of interconnected ion-transport pathways. In situ infrared spectroscopy confirms the pivotal role of framework carboxylates (R–COO^-) and hydroxyls (R–OH) groups in coordinating Li⁺ and enabling solid‐state ion hopping. Electrochemical impedance spectroscopy demonstrates a significant enhancement in ionic conductivity, with Li/Zr-MOG-3 achieving 1.54 × 10⁻² S cm⁻¹ at 383 K under anhydrous conditions, 8-fold higher than pristine Zr-MOG. The low activation energy (0.12–0.21 eV), determined via Arrhenius analysis, indicate an efficient ion hopping mechanism in the absence of water molecules. These findings highlight the potential of defect‐engineered, humidity‐independent Zr-MOG as high‐performance solid‐state Li⁺ electrolytes, and provide fundamental insight into the role of defect chemistry and functional‐group interactions in optimizing ion mobility.