1. UKM Learning and Research Repository
2. PHD Thesis / Tesis PHD
3. Faculty of Science and Technology / Fakulti Sains dan Teknologi

Title:	Development of high-performance piezoelectric nanogenerator based on BaTiO3/PVDF nanocomposite fibers
Authors:	Ibtehaj Zoheer Khalid Khatatbeh (P90632)
Supervisor:	Mohammad Hafizuddin Jumali, Assoc. Prof. Dr.
Keywords:	Energy Piezoelectric nanogenerator Nanocomposite fibers Universiti Kebangsaan Malaysia -- Dissertations Dissertations, Academic -- Malaysia
Issue Date:	15-Jul-2021
Description:	Small but huge potential energy from naturally occurring vibrations can be collected using piezoelectric nanogenerators (PNGs). Despite greater flexibility and being environmentally friendly, poly (vinylidene fluoride) PVDF-based PNGs performance is significantly inferior to its PbTiO3 counterparts. To achieve greater performance, PVDF molecules not only have to be iezoelectric active, but also must be properly aligned. To achieve these conditions, high-electric field poling process is commonly used. The ultimate aim of this research is to fabricate high-performance PNG based on BaTiO3/PVDF nanocomposite fibers (NCFs) using a novel technique without a poling process. This work is divided into two parts. The first part focused on the production of PVDF fibers using a home-made fast-centrifugal spinning system. Two preparation parameters, namely the ratios between the solvents (N, N-Dimethylformamide (DMF) and acetone) and the spinning speed were studied. At optimum volume ratio DMF: acetone of 30: 70 and spinning speed of 8000 rpm, the smooth, long and beads-free PVDF fibers with β-phase reaching 95% and piezoelectric coefficient of -152 pC.N-1, was successfully produced. The PNGs fabricated from the optimum fibers displayed open-circuit voltage (VOC), short-circuit current (ISC) and power density of 22 V, 2.2 μA and 12.6 μW.cm-2 respectively. In the second part, different wt.% of the tetragonal BaTiO3 nanoparticles (NPs) prepared via sol-gel method were added into the optimum PVDF solution to produce NCFs.Interestingly, the PNGs based on the NCFs not only showed high mechanical durability, but also exhibited dramatic performance improvements. At optimum 50 wt.% NPs content,the recorded VOC, ISC and power density were 160 V, 16 μA and 980.2 μW.cm-2 respectively. This performance is the best among all BaTiO3/PVDF composite PNGs up to date. The remarkable improvement stemmed from self-alignment characteristics of the fibers, as evidenced from Piezo-response Force Microscopy (PFM) measurements.Excitingly, the self-alignment of PVDF molecules induced the dipoles re-orientation in the NPs. Unfortunately, above 50 wt.% NPs, the PNGs based on the NCFs showed a reduction in performance. The practical application of the PNG was demonstrated when 7 commercial red LEDs in series were effectively lit up directly from the device. Similarly, 32 coloured LEDs in parallel were successfully lit up if the generated energy is stored in the 10 μF capacitor. This work successfully demonstrated that the high-performance NCF-PNGs can be fabricated using a cost-effective technique. As a result, the fabricated NCF-PNGs in this work have shown a vast potential to be used as a flexible lead-free energy harvester, in order to collect small wasted energies from various types of motion that are plenty in our surrounding environment and daily life activity.,Ph.D.
Pages:	172
Publisher:	UKM, Bangi
Appears in Collections:	Faculty of Science and Technology / Fakulti Sains dan Teknologi

Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.