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Title:	Salt-polymer-solvent ternary electrolyte system: salt solubility and ion mobility of LiCl04 in polymer solution
Authors:	Hussein Hanibah (P67321)
Supervisor:	Azizan Ahmad, Prof. Dr.
Keywords:	Salt solubility Ion mobility Polymer electrolyte Electrolyte system Dissertations, Academic -- Malaysia
Issue Date:	3-Nov-2016
Description:	This research focused on the fundamental theory of salt solubility and ion mobility (K') in different liquid electrolyte systems. Electrolytic conductivity (κ) at 25.0 °C was measured using an AC conductivity meter. Potassium chloride (KCl) solutions with different concentrations were used to calibrate the platinum electrode under nitrogen atmosphere. The molar conductivity at infinite dilution (0) of a weak lithium perchlorate (LiClO4) electrolyte dissolved in organic solvent such as acetronitrile (ACN) and tetrahydrofuran (THF) was extrapolated after Ostwald's dilution law. The estimated Λ0 values for both LiClO4 in ACN and THF are 24200 and 76 S cm2 mol-1, respectively this estimation for both weak electrolyte systems show a huge deviation from the expected values at 155.3 and 173.0 S cm2 mol-1. This indicates the limitation of Oswald's dilution law in estimating the Λ0 values for weak electrolytes in an organic solvent. Therefore a new mathematic equation (power law) has been proposed to determine the Λ0 with a better accuracy for the liquid electrolyte system especially in an organic solvent. Double-logarithmic plot of κ versus Csalt was introduced to determine the Λ0. The proposed power law is fulfilled to the basic linear graph equation for certain (finite) range of Csalt = 10-8 - 10-6 mol cm-3. Hence, a controlled electrolyte system strong aqueous LiClO4 (electrolyte) have been used to estimate the reference salt concentration (Cref) before it was further applied to weak electrolyte systems. It is noted that, Cref for each system that corresponds to the Λ0 is approximately half that of the lowest Csalt concentration and it still obeys the power law before the data starts to divert from the linearity of the power law. Then by using new mathematic equation the salt solubility and K' value for each electrolyte has been estimated. In order to estimate Λ0 value at 25.0 °C for LiClO4 in liquid polymer electrolytes [poly(ethylene oxide) (PEO), poly(methyl methacrylate) (PMMA), poly(methylmethacrylate-co-methacrylic acid) (PMMA-co-MA) – binary system], [PEO5 blend with PMMA and PEO5 blend with PMMA-co-MA – ternary system], the Cref = 1.89·10-9 mol cm-3 was adopted. The κ value of the LiClO4 in polymer solutions was measured as a function of Csalt. The polymer solutions comprised of fixed polymer concentrations (Cpoly) for each electrolyte system. Consistent with Cpoly and the increasing values of Mw in the electrolyte system, Λ0 values tend to show a descending trend that indicates a better salt solubility in a binary system compared to a ternary system. In general, the K' and κ values showed an increasing trend in the ternary electrolyte system as the polarity increases. As a complement, a new mathematic equation has been proposed to account for the phase diagram of the salt dissociation (α) for each electrolyte system. Based on the phase diagram, the α of PEO electrolyte with higher Mw in the presence of a co-polymer in the electrolyte show an improvement of α and K' values of the liquid polymer electrolyte.,Certification of Master's/Doctoral Thesis" is not available
Pages:	227
Publisher:	UKM, Bangi
Appears in Collections:	Faculty of Science and Technology / Fakulti Sains dan Teknologi

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