Impedance spectroscopy studies of poly (methyl methacrylate)-lithium salts polymer electrolyte systems

Abstract

In the present work, five systems of samples have been prepared by the solution casting technique. These are the plasticized poly(methyl methacrylate) (PMMA-EC) system, the LiCF 3 SO 3 salted-poly(methyl methacrylate) (PMMA-LiCF 3 SO 3 ) system, the LiBF 4 salted-poly(methyl methacrylate) (PMMA-LiBF 4 ) system, the LiCF 3 SO 3 salted-poly(methyl methacrylate) containing a fixed amount of plasticizer ([PMMA-EC]-LiCF 3 SO 3 ) system, and the LiBF 4 salted-poly(methyl methacrylate) containing a fixed amount of plasticizer ([PMMA-EC]-LiBF 4 ) system. The conductivities of the films from each system are characterized by impedance spectroscopy. The room temperature conductivity in the pure PMMA sample and (PMMA-EC) system is 8.57×10 −13 and 2.71×10 −11 S cm −1 , respectively. The room conductivity for the highest conducting sample in the (PMMA-LiCF 3 SO 3 ), (PMMALiBF 4 ), ([PMMA-EC]-LiCF 3 SO 3 ), and ([PMMA-EC]-LiBF 4 ) systems is 3.97×10 −6 , 3.66×10 −7 , 3.40×10 −5 , and 4.07×10 −7 S cm −1 , respectively. The increase in conductivity is due to the increase in number of mobile ions, and decrease in conductivity is attributed to ion association. The increase and decrease in the number of ions can be implied from the dielectric constant, ɛ r -frequency plots. The conductivity-temperature studies are carried out in the temperature range between 303 and 373 K. The results show that the conductivity is increased when the temperature is increased and obeys Arrhenius rule. The plots of loss tangent against temperature at a fixed frequency have showed a peak at 333 K for the ([PMMA-EC]-LiBF 4 ) system and a peak at 363 K for the ([PMM-EC]-LiCF 3 SO 3 ) system. This peak could be attributed to β-relaxation, as the measurements were not carried out up to glass transition temperature, T g . It may be inferred that the plasticizer EC has dissociated more LiCF 3 SO 3 than LiBF 4 and shifted the loss tangent peak to a higher temperature.

Preparation and characterization of blended solid polymer electrolyte 49% poly(methyl methacrylate)-grafted natural rubber:poly(methyl methacrylate)–lithium tetrafluoroborate

“…This indicates that the electrolyte system exhibited nonArrhenius-like behavior in the temperature range from 303 to 323 K. This is the result of the β-relaxation of the PMMA segment as reported by Othman et al [37]. The β-relaxation peak at 333 K was attributed to the main chain mobility below the glass transition temperature, T g of PMMA.…”

“…This indicates that the electrolyte system exhibited Arrhenius-like behavior given by Arrhenius equation: σ0σ o e (−Ea/kT) , where σ o , E a , and k represent the pre-exponential factor, activation energy, and Boltzmann constant (k08.6× 10 −5 eV K −1 ), respectively [36]. The value for σ o and E a is calculated from the y-axis and plot intercept between log σ and 1,000/T [37]. −E a /kT is represented by the graph slope, m. From the Arrhenius plot, the activation energy E a is 0.46 eV, while the pre-exponential factor σ o is 1.21 × 10 −7 S cm −1 .…”

Effect of ethylene carbonate plasticizer and TiO2 nanoparticles on 49% poly(methyl methacrylate) grafted natural rubber-based polymer electrolyte

“…Therefore, the ions can easily migrate through the void and resulting in ionic conductivity enhancement. High dielectric constant and low viscosity of plasticizers also enable them to incorporate with the polymer host to facilitate the formation of dissociated ions [2,5,10]. The plasticization is also the conventional way to reduce the crystallinity and increase the amorphous phase of polymer electrolyte in order to increase the mobility of the ions and generate higher ionic conductivity [11].…”

Genipin-Crosslinked Gelatin-Based Emulgels: an Insight into the Thermal, Mechanical, and Electrical Studies

“…An increase in the oil proportion resulted in increase in the tan δ peak. The loss in cG3 and cG5 were insignificant suggesting similar viscoelastic properties (47,48). The conductivities of the emulgels suggested frequency independent behavior at lower frequencies which got dispersed at higher frequencies (Fig.…”

“…All the formulations contained gelatin as the polymer and explains the occurrence of the tan δ peak at the same frequency (Fig. 5c) (47). Since the crosslinking density was varied in the formulations, the amount of loss was higher.…”