Stimulated storage capabilities and cyclic stability of Li₃VO₄ anode material via NaF-assisted mechanochemical surface coating for robust Li-ions batteries

The rapid demand for electrical energy storage batteries for renewable energy necessitates working on the availability of electrode materials with high stability properties, long lifespan, and superior storage capacities. To meet these needs, a novel ceramic electrode material based on NaF-coated Li₃VO₄ (NaF@LVO) was developed to be integrated in Li-ion batteries as a powerful anode with excellent electrochemical characteristics. The advanced characterization tools such as FESEM, HRTEM, Raman/FTIR spectroscopy, XRD, BET and XPS were employed to inspect the as-prepared pristine LVO and its NaF coating layer with different percentages. The results of XRD patterns showed a small shift in the main peaks of the orthorhombic phase as a result of the inclusion of large Na atoms in the vacant lattice sites. FESEM and HRTEM showed a clear agreement that the highly agglomerated quasi-spherical LVO particles are converted into less agglomerated platelet particles after NaF mechanochemical coating with a remarkable increase in the particle size from 50-150 nm to 150-300 nm. NaF surface engineering of the LVO structure revealed a splitting and shift in the main Raman spectra (770-880 cm⁻¹) to higher wavenumbers, confirming the crystallinity enhancement. The half and full cell electrochemical testing of 3 wt%NaF-modified LVO anode demonstrated the maximum discharge capacities ∼518 mAh·g⁻¹ versus Li/Li⁺ and ∼121 mAh·g⁻¹ versus commercial LFP cathode. Cyclic voltammetry (CV) and electrochemical impedance studies (EIS) confirmed the accelerated diffusion kinetics and enhanced charges transfer after NaF-coating with 3 wt%. The improved cyclic stability after NaF-assisted mechanochemical coating of pristine LVO particles was attributed to the combined effects of lattice modifications, enhanced surface activity and additional interfacial storage contributions.