“…Figure 8 shows plots of the dc conductivity as a function of the inverse of temperature for different MWCNT concentrations in the (PEO) 4 CF 3 COOLi electrolyte. For all systems, it is observed that the dc conductivity increases with increasing temperature following the Vogel Tamman Fulcher (VTF) equation [ 18 , 32 ]: where σ dc is the conductivity obtained in the plateau, σ 0 is the pre-exponential factor, E A is a parameter known as pseudo-activation energy, k B is the Boltzman constant, T is the absolute temperature, and T 0 stands for the temperature (below the glass transition temperature) at which the free volume, responsible for ionic conduction, disappears, and the ionic conductivity cancels out. Table 6 shows the parameters for the fitting to Equation (2).…”