Citation

Koh, Eric Renwei (2021) Simulation And Experimental Studies of Electrical Properties in Poly (Methyl-Methacrylate) Solid Polymer Electrolytes With Fillers. Masters thesis, Multimedia University.

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Abstract

Solid polymer electrolytes (SPEs) are a safer alternative over liquid (LPEs) and gel polymer electrolytes (GPEs) systems. SPEs are safer for consumers due to their better thermal stability, low toxicity, and low explosion risk. Despite the potential advantages, SPEs suffer from a high degree of crystallinity and high interfacial resistance at ambient temperature, leading to low ionic conductivity and lithium transference number. PMMA SPEs were known to be a semi-amorphous polymer with improved mechanical and thermal properties over GPEs and LPEs but still capable of exhibiting good ionic conductivity in the range of 10-4 S/cm and lithium transference number of ≥0.1 at room temperature. However, most of the studies to date were focused on PMMA GPEs and there were not many studies related to PMMA SPEs and their lithium transference number. In this work, lithium transference number and ionic conductivity of PMMA SPEs doped with inorganic fillers were studied using various electrochemical characterisation techniques, and the Monte Carlo (MC) method was used to study the ion transport properties in PMMA SPEs. Electrochemical impedance spectroscopy (EIS) and DC polarisation technique demonstrated that PMMA SPEs with SiO2 fillers (10≤µm) could achieve ionic conductivity of 2.35×10-4 S/cm and lithium transference number of 0.263 at room temperature. Moreover, linear sweep voltammetry (LSV) shows that PMMA SPEs have an electrochemical stability window of greater than 3.0 V, and cyclic voltammetry (CV) demonstrated that PMMA SPEs doped with inorganic fillers had improved charge storing capability and energy density. Besides that, Al2O3 and SiO2 fillers enhanced PMMA SPEs also show greater discharging capacity than PMMA SPEs without inorganic fillers through discharging test. Ion transport properties of Li+ ions under different electric field strength were also investigated using single ion MC model. It is shown that the mean drift velocity of Li+ ions and the average energy governed by Li+ ions are greatly dependent on the electric field strength. The velocity of Li+ ions increases in a linear fashion when the electric field rises from 0.1kV/cm to 3.0kV/cm as electromagnetic forces are stronger at higher electric field regions. Moreover, the energy of Li+ ions also increases as the electric field increases. Since Li+ ions travel in the same direction of the applied electric field, the greater forces exerted by stronger electric field speed up Li+ ions velocity. As a result, the total amount of energy carried by Li+ ions is also higher due to the increases in kinetic energy.

Item Type:	Thesis (Masters)
Additional Information:	Call No: QD382.P64 K64 2021
Uncontrolled Keywords:	Polyelectrolytes
Subjects:	Q Science > QD Chemistry > QD241-441 Organic chemistry
Divisions:	Faculty of Engineering and Technology (FET)
Depositing User:	Ms Nurul Iqtiani Ahmad
Date Deposited:	22 May 2023 08:04
Last Modified:	22 May 2023 08:04
URII:	http://shdl.mmu.edu.my/id/eprint/11426

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