Study of polymer electrolyte for energy storage device

Lee, Woi Jing Yuan (2026) Study of polymer electrolyte for energy storage device. Final Year Project, UTAR.

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Abstract

The development of high-performance solid polymer electrolytes (SPEs) is critical for the advancement of safe and efficient solid-state energy storage devices, such as Electric Double-Layer Capacitors (EDLCs). This study investigates the enhancement of a poly(ethyl methacrylate) (PEMA) and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) host matrix through the incorporation of various ceramic fillers, specifically Barium Titanate (BaTiO₃), Lithium lanthanum zirconium tantalum oxide (LLZTO), Titanium Dioxide (TiO₂), and Zinc Oxide (ZnO). Using the solution casting method, composite membranes were fabricated and characterized to evaluate their structural and electrochemical properties. Material characterization via XRD and SEM revealed that while the electrolytes remained predominantly amorphous, the micro-sized (~20 μm) filler particles led to localized dispersion challenges and interfacial wetting issues. Electrochemical analysis identified the 2 wt% BaTiO₃ formulation (BSPE-2) as the optimal composition, achieving a superior ionic conductivity of 5.28 × 10⁻⁵ S/cm and an exceptionally wide stability window of 6.2 V. When integrated into an EDLC, the system demonstrated a specific capacitance of 11.02 F/g, an energy density of 0.462 Wh/kg, and a power density of 83.14 W/kg. However, cyclic stability testing showed a significant 55.5% energy density drop over 500 cycles, indicating poor long-term durability. It is concluded that while BaTiO₃ significantly boosts short-term performance and voltage stability, the large particle size contributes to mechanical degradation. Future recommendations include transitioning to nano-sized fillers and refining fabrication techniques, such as doctor blade coating and the addition of solid plasticizers, to ensure interfacial integrity and commercial viability. Keywords: Solid polymer electrolyte; PEMA; BaTiO3; EDLC; Ionic conductivity; Ceramic fillers Subject Area:

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