Browsing by Author "Ratnasekera, J.L."
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Item Polyacrylonitrile Based Gel Polymer Electrolyte for Rechargeable Magnesium Ion Batteries(Uva Wellassa University of Sri Lanka, 2020) Dias, N.A.T.H.; Pitawala, H.M.J.C.; Ratnasekera, J.L.; Bandara, T.M.W.J.; Nayanakanthi, M.D.M.The demand for energy storage devices has highly increased with the increment of the demand for electronic portable devices and electric vehicles. Therefore, developing rechargeable batteries has received the most attention. Among the components of a rechargeable battery, electrolyte is highly concerned as it is the medium for the transfer of charges between the pair of electrodes. Developing gel polymer electrolytes is mostly explored due to its favourable performances and minimum drawbacks compared to liquid electrolytes and solid electrolytes. In this research polyacrylonitrile based gel polymer electrolyte for magnesium ion batteries was prepared and characterized to investigate its physicochemical properties. Preparation of gel polymer electrolytes was carried out by a common solution casting technique using dimethyl sulfoxide as the solvent, magnesium trifluoromethanesulphonate as the salt and 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide as the ionic liquid. Impedance spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction, and Differential scanning calorimetry was performed to analyse the prepared electrolyte samples. The maximum room temperature ionic conductivity of 2.33×10-3 S cm-1 and 3.33×10-3 S cm-1 were obtained for the sample before and after the addition of ionic liquid respectively. Considerable indications for the polymer-solvent, polymer-salt, and polymer-salt-ionic liquid interactions were investigated by analysing Fourier transform infrared spectroscopy. Although the crystallinity has increased with the addition of salt due to the formation of ion pairs and aggregates, the effect has been preserved with the addition of ionic liquid. The glass transition temperature has also increased from 80 0C to 104 0C after the coordination of polyacrylonitrile with magnesium trifluoromethanesulphonate, however, it is reduced to 102 0C after the addition of ionic liquid. Keywords: Gel polymer electrolyte, Polyacrylonitrile, Magnesium trifluoromethanesulphonate, Ionic liquid, Ionic conductivityItem Transport Properties and Interactions of Ionic Liquid Doped Bio Polymer based Gel Electrolyte for Sodium Rechargeable Batteries(Uva Wellassa University of Sri Lanka, 2019) Kawshalya, D.H.N.; Ratnasekera, J.L.; Pitawala, H.M.J.C.The interest in gel polymer electrolytes (GPEs) as electrolyte materials for rechargeable thin film batteries has boosted in the last years. In general, different synthetic polymers are used in gel electrolyte preparation, the reports on biodegradable polymers are lacking. In this work, a gel electrolyte was prepared by solvent casting method using NaClO4 salt and commercially available biopolymer i.e. agar which is extracted from marine algae. The effect of addition of an ionic liquid (IL) in this parent electrolyte was investigated using N-Butyl-N-methylpyrrolidinium bis(triflouromethylsulfonyl)imide (PyR14TFSI). The IL incorporated membranes were transparent, freestanding and flexible. The ionic conductivity of the membranes was obtained using complex impedance spectroscopy whereas the polymer-salt and polymer-IL interactions were investigated using FT-IR spectroscopy. The crystallinity of the electrolytes was investigated by XRD. Our results show that the maximum ionic conductivity of 5.51 x 10-4 S cm-1 at room temperature can be obtained with the electrolyte having 12 wt% of NaClO4 without IL. The incorporation of 10 wt% of the PyR14TFSI into this parent electrolyte shows further enhancement in ionic conductivity up to 1.03 x 10-3 S cm-1 at room temperature. FTIR results show weak but noticeable changes due to the interactions of IL with the polymer. The reduction of crystalline phases and increase of amorphous nature with the IL is revealed that the IL has a major influence on the transport properties of the electrolyte due to structural modifications associated with the polymer host and also due to the reduction of Na+ ion and polymer coordination in the IL incorporated electrolyte.