Synthesis and investigation on the structural and complex impedance analysis in LISICON compound, Li3Al2(PO4)3, for solid electrolyte battery applications

Abstract

LiSICON materials have gained significant attention due to their exceptional ionic conductivity at elevated temperatures, positioning them as promising candidates for energy storage and other emerging applications. This study investigates Li₃Al₂(PO₄)₃, a compound with notable potential as a solid electrolyte. X-ray diffraction (XRD) confirmed the crystalline phase, while scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) provided insights into its morphology and composition, ensuring accurate stoichiometry. The electrical and dielectric properties were investigated using complex impedance spectroscopy (CIS), revealing a high sensitivity to frequency and temperature. Detailed impedance measurements across various conditions elucidated the material’s behavior, with Nyquist plots indicating contributions from both grains and grain boundaries, characteristic of non-Debye-type relaxation. Jonscher’s power law was applied to the AC conductivity data, demonstrating that the conduction mechanism aligns with the correlated barrier hopping (CBH) model, driven by the hopping of Li⁺ ions. Notably, Li₃Al₂(PO₄)₃ exhibited a high permittivity value (ε ~ 10⁴), indicating excellent dielectric properties and significant energy storage capacity. These findings underscore the potential of Li₃Al₂(PO₄)₃ as a high-performance solid electrolyte for high-temperature applications, particularly in energy storage devices.