Polymethyl methacrylate – polylactic acid as hybrid gel polymer electrolytes for li+ ions battery application /
Norfatihah Binti Mazuki
- xiv, 242 pages ; illustration ; 1 CD-ROM
Faculty of Industrial Sciences and Technology
Thesis (Doctor of Philosophy) -- Universiti Malaysia Pahang – 2024
Includes bibliographical references
The introduction of polymer electrolytes in 1970 revolutionized electrochemical devices by providing a safer alternative to traditional electrolytes, making electrolytes essential components in the field. Thus, this research focuses on developing a novel Hybrid Gel Polymer Electrolyte (HGPE) tailored for lithium-ion batteries, comprising two systems: PMMA-PLA-LiTFSI (System I) and PMMA-PLA-LiTFSI-[EDIMP]TFSI (System II). These systems employ a hybrid polymer host of PMMA and PLA, with LiTFSI as the ionic dopant salt and [EDIMP]TFSI as the ionic liquid. The study investigates the physicochemical, ionic conduction, and electrochemical characteristics of these HGPEs. Fourier Transform Infrared Spectroscopy (FTIR) confirms interactions between PMMAPLA, LiTFSI, and [EDIMP]TFSI, while X-ray Diffraction (XRD) and Differential Scanning Calorimetry (DSC) analyses reveal increased amorphous phase and enhanced flexibility in polymer chains with higher lithium salt and ionic liquid content. Ionic conductivity improves from 1.02 × 10-3 S cm-1 (20 wt.% LiTFSI) to 3.90 × 10-3 S cm-1 with 20 wt.% [EDIMP]TFSI. Temperature-dependent behavior follows an Arrhenius pattern, with lower activation energy inversely correlated to increased conductivity. NonDebye characteristics are observed in the permittivity spectra. Arof-Noor (A-N) method determines ionic mobility, charge carriers, and diffusion coefficient, elucidating factors influencing ionic conductivity variations. The highest-conductivity HGPEs (20 wt.% LiTFSI and 20 wt.% [EDIMP]TFSI) exhibit enhanced lithium transport number (tLi + ) and widened electrochemical stability window (from 4.3V to 5V). Selected HGPE samples are employed in LiǀHGPEsǀGraphite cells, yielding discharge capacities of 152.06 mAh g -1 and 71.15 mAh g-1 for 20 wt.% LiTFSI and 20 wt.% [EDIMP]TFSI electrolytes, respectively, at 3.72 A g-1 . These promising results highlight the potential of the PMMAPLA-based HGPEs for lithium-ion battery applications, with further studies recommended for compatibility investigations between electrode and electrolyte materials.
THE0009925 (Local)
Faculty of Industrial Sciences and Technology--Dissertations