AC Conductivity In PEO And Cocl2

Improved Essays
AC conductivity: Figure 4.19(a) shows the frequency dependent electrical conductivity of PCL5 electrolyte. The result shows that AC conductivity changes with temperature. The AC conductivity of the PEO/CoCl2 electrolyte increases with temperature is given in Table 4.4, which is the common characteristic of disordered materials. An increase in ac conductivity with frequency and temperature indicates charge transported by hopping through the defect sites along the polymer chain [70]. Also the increase in electrical conductivity with increasing temperature is due to the buildup of ordered polycondensed rings, which allow charge transport. This temperature dependence of conductivity at higher temperatures suggests that the hopping mechanism of …show more content…
Figure 4.22(a) shows the sharp endothermic peak observed and the melting temperature of PEO at 67 oC has been decreased to 54.4 oC for 5 wt%. The decrease in melting point (Tm) might be related to a decrease in the relative percentage of crystallinity (χc) of the film. The endothermic curves also indicate a reduction in PEO crystallinity. The study of the degree of crystallinity is very significant one to understand the change in the thermal characteristics induced due to CoCl2. The relative percentage of crystallinity χc has been calculated using Equation (2.20) and the values of Tg, Tm, ΔHm and χc are summarized in Table …show more content…
These results are well agreed with the XRD results [74]. Decrease in the percentage of χc designates that Co2+ effectively distorted the main chain dynamics of PEO. The value of Tg was decreased from –68 to –80 oC with the increase of CoCl2 concentration are shown in Figure 4.22(b). Above glass transition temperature, the polymeric chain becomes more flexible resulting in enhanced segmental mobility of the PEO polymer chain. Lower Tg usually leads to easier chain relaxation and is associated with fast ion conduction mechanism

Related Documents

  • Improved Essays

    So, it is observed that Schmidt number enhances the temperature. Meanwhile, the higher values of Schmidt number correspond to a reduction in the particles diffusion. So, the concentration decreases with increasing . Fig.6 illustrates that, the Prandtl number reduces the temperature. An increase of Prandtl number means a slow rate of thermal-diffusion.…

    • 899 Words
    • 4 Pages
    Improved Essays
  • Improved Essays

    Cumnox Reaction Lab Report

    • 1018 Words
    • 5 Pages

    The crystallinity was also increased as the increasing of the calcination temperature of the precursor, therefore the diffraction peaks at the XRD analysis was more crystalline phases produced by calcination at (200 - 400oC) temperature. The catalyst calcined at 300oC for 2hr showed the best catalytic activity for complete oxidation of CO at 120oC temperature. The increases calcination temperature resulting increases the oxidation…

    • 1018 Words
    • 5 Pages
    Improved Essays
  • Improved Essays

    This led to an increase in resistivity and a decrease in the conduction. The value of activation energy from table 2 indicates that the conduction process in the present Co-Cr nano ferrite system is due to hopping of polarons. The substitution of Cr ion cobalt ferrites results in the formation of stable electric bonds between the Cr3+ and Fe2+ ions. This localizes Fe2+ charge carriers and hampers the Verwey mechanism thus increasing the resistivity. A similar behavior was reported in case of Ni-Al ferrite system [23] and Bi2O3 doped CoFe2O4…

    • 1962 Words
    • 8 Pages
    Improved Essays
  • Improved Essays

    When temperature gets higher, atoms of the structure moves vigorously that creates vibration and thus amplitude of alpha increases. As for tilting, it only changes the angle, but…

    • 1099 Words
    • 5 Pages
    Improved Essays
  • Great Essays

    CO2 Partial Pressure

    • 1624 Words
    • 7 Pages

    B. Pressure Effect of CO2 partial pressure (PCO2) is related to solution pH as well. In the condition where scale-free CO2 corrosion occurs, the increase of PCO2 will increase the corrosion rate. This can be explained by the increment of H2CO3 concentration…

    • 1624 Words
    • 7 Pages
    Great Essays
  • Improved Essays

    When there is an increase in pressure, it will lead to a phase change. This causes the octahedral Fe centres to become denser. It will thus lead to the formation of β-FePO4. This transition of α-FePO4 to…

    • 945 Words
    • 4 Pages
    Improved Essays
  • Improved Essays

    Feipo4 Reaction Lab Report

    • 1054 Words
    • 5 Pages

    With that being said, both have the same extent of symmetry and the Atoms drawings are rather similar. Furthermore, the rise in temperature shows that the cell parameter will increase greatly, leading to an overall increase in volume. However, as temperature rises up to 980K, there will be a great difference in terms of the structure of the crystals. This would thus lead to a decrease in the c/a ratio as temperature increases, showing an inverse relationship between the two. Hence, when the temperature rises from low (240K) to a high of (980K) the refined structural parameters would thus change from α to β.…

    • 1054 Words
    • 5 Pages
    Improved Essays
  • Improved Essays

    Feed Flow Rate Essay

    • 800 Words
    • 4 Pages

    4.6: Effect of Regenerated Catalyst flow rate on the yield of y1 (Gas oil), y2 (Gasoline), y3 (light gases) and y4 (coke). Operating conditions: Tf = 790K; Trg = 960K; Fgr = 67.8Kg/s; Frc = 3*67.8Kg/s: 5: 14.7*67.8Kg/s; 4.2.6 Effect of Catalyst- to- Oil Ratio (COR) The changing of values for the catalyst - to - oil ratio (COR) in the riser mainly affect yield of various products. Due to more catalyst flow rate, the number of active sites increases, causing more cracking, increasing conversion of gas oil and yield of fuel gases and coke. The activity of the catalyst decreases after some time due to deactivation of catalyst by deposition of coke and drop in gasoline yield occur as well (Prabha et al. 2012).…

    • 800 Words
    • 4 Pages
    Improved Essays
  • Improved Essays

    Fepo4 Temperature

    • 718 Words
    • 3 Pages

    From the research, the equation of δ2 =2/3 δ0 2 [1+(1-3/4(T-Tc/T0-Tc) ^1/2] shows the changing correlation of tilt angle δ with temperature from α phase to β phase. The δ0 is the decreased tilt angle at 980K and Tc is the temperature for the second-order transition. FePO4 structural behavior is different from other α-quartz homeotypes as the tilt angle δ decreases faster than quartz. Figure 1: Crystal structure of quartz Figure 2: Crystal structure α-phase FePO4 Paragraph 2 Figure 3: The variation graphs of cell parameters and cell volumes with temperatures The α-β transition happens when the temperature increases from 294K to 980K. The α- FePO4 cell has a trigonal structure with lattice parameters a=b=c and…

    • 718 Words
    • 3 Pages
    Improved Essays
  • Improved Essays

    Both of these factors result in the structure of FeO4 to change in size as temperature increases. By the same token, the O-P-O angles change as temperature increases, while the P-O bond distances change as temperature increases. This results in a change in size in the structure of PO4 as temperature increases. The equation δ^2 = 2/3 δ0^2 [1 + (1 – ¾ (T – Tc/T0 – Tc))^1/2] can be used here to describe quantitatively how the temperature affects the cell parameter and size, as we have earlier established how temperature affects the tilt angle which affects the cell parameter and…

    • 895 Words
    • 4 Pages
    Improved Essays