TiO₂-reinforced PVA/HPMC/CMC ternary bio-blend electrolytes for advanced energy storage devices

Abstract

This study develops and characterizes eco-friendly ternary polymer electrolytes composed of polyvinyl alcohol (PVA), hydroxypropyl methylcellulose (HPMC), and carboxymethyl cellulose (CMC), reinforced with titanium dioxide (TiO₂) nanoparticles, for high-performance energy-storage applications. PVA/HPMC/CMC/TiO₂ nanocomposites were fabricated via solution casting and characterized using XRD, FTIR, UV–Vis spectroscopy, SEM, TEM, and impedance spectroscopy to investigate their structural, optical, dielectric, and electrical properties. XRD results revealed that the incorporation of TiO₂ suppressed crystallinity and promoted the formation of an amorphous phase, thereby favoring ion mobility. Optical analysis revealed band-gap narrowing with the addition of TiO₂ (4.63 eV direct, 2.88 eV indirect), indicating enhanced electronic transitions and light absorption. Impedance measurements demonstrated optimized ionic conductivity (2.63 × 10⁻⁷ S cm⁻¹ at 1.2 wt% TiO₂) and a high dielectric constant (∼1264), resulting from interfacial polarization and additional conduction pathways. A pronounced decrease in bulk resistance (1.5 kΩ at 1.2 wt% TiO₂ vs. 8.2 kΩ for the pristine blend) further confirmed enhanced charge transport with reduced energy loss-key factors for high-performance capacitors and microelectronic devices. These findings highlight the crucial role of TiO₂ nanoparticles in tuning and tailoring the functional properties of PVA/HPMC/CMC electrolytes, thereby providing a sustainable, scalable, and cost-effective platform for next-generation capacitive energy storage systems.