Synergistic enhancement of electrical and ionic conductivity in polyvinyl alcohol/polyvinylpyrrolidone‑copper/lithium titanate oxide electrolyte nanocomposite films for Li-ion battery applications

Abstract

Herein, we report the development of polymer nanocomposite electrolyte films tailored for advanced Li-ion battery applications. By incorporating copper/lithium titanate oxide nanoparticles (Cu/Li₄Ti₅O₁₂ NPs) into a polyvinyl alcohol/polyvinylpyrrolidone (PVA/PVP) blend, we achieved significant enhancements in both ionic and electrical conductivity. The incorporation of Cu boosts the electrical pathways within the polymer matrix, thereby reducing internal resistance and enhancing the overall conductivity. Simultaneously, Li₄Ti₅O₁₂ acts as an additional source of Li ions, further elevating ionic transport within the electrolyte. Comprehensive analyses via dielectric and impedance spectroscopy confirmed the influence of Cu/Li₄Ti₅O₁₂ NPs on improving charge storage and transfer capabilities while minimizing electrode polarization across a wide frequency range. These enhancements are attributed to the homogenous distribution of NPs, as validated by scanning electron microscopy (SEM), and the adjusted crystalline characteristics confirmed via X-ray diffraction, leading to increased amorphous regions that support better ion mobility. Fourier-transform infrared spectroscopy (FTIR) also confirms NP-matrix interactions, altering polymer chain dynamics. Besides, thermogravimetric analysis (TGA) indicates increased thermal stability. The results indicate the promising capabilities of these nanocomposite films as efficient solid polymer electrolytes, capable of supporting faster charge-discharge cycles and ensuring enhanced performance and stability in Li-ion batteries.