Comprehensive structural and electrical characterization of lithium metavanadate for advanced lithium-ion battery cathodes

Abstract

Lithium metavanadate (LiVO₃) is a material of growing interest due to its monoclinic C2/c structure, which supports efficient lithium-ion diffusion through one-dimensional channels. This study presents a detailed structural, electrical, and dielectric characterization of LiVO₃ synthesized via a solid-state reaction, employing X-ray diffraction (XRD), scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS), and impedance/dielectric spectroscopy across a temperature range of 473–673 K and frequency range of 10 Hz to 1 MHz. XRD and Rietveld refinement confirmed high crystallinity and single-phase purity with lattice parameters a = 10.155 Å, b = 8.421 Å, c = 5.881 Å, and β = 110.45°. XRD confirmed single-phase purity and lithium stoichiometry, while SEM-EDS verified the uniform distribution of vanadium and oxygen, supporting chemical homogeneity. Impedance spectroscopy revealed thermally activated conduction with distinct grain (0.86 eV) and grain boundary (0.77 eV) activation energies, modeled using an equivalent circuit with constant phase elements, highlighting significant microstructural effects. AC conductivity follows Jonscher's universal power law, driven by a single-polaron hopping mechanism with strong electron-phonon coupling. Dielectric analysis showed pronounced non-Debye relaxation and space-charge polarization, influenced by temperature, frequency, and grain boundaries. These results elucidate the critical role of microstructure in governing charge transport and dielectric relaxation in LiVO₃, supporting its potential as a candidate material for lithium-ion battery cathodes. Targeted doping and interface engineering are proposed as promising future strategies to enhance its electrochemical properties, thereby advancing its applicability in energy storage research.