3.1.2 Transference Number Measurement
Using Wagner’s direct-current polarisation approach, illustrated in fig. 3, the total ionic transference number of the produced electrolyte comprised of solid, flexible polymers was computed. This approach is based on adopting suitable electrodes for a mixed conductor, it is possible to suppress either ionic or electronic transport while still determining the contribution of unsuppressed species. This approach involves sandwiching the sample between two electrodes, one of which is reversible (non-blocking) and can interchange both ions and electrons with the electrolyte, and the other of which is blocking (non-reversible) and can only do so. In order to polarise the sample, an insignificant potential is provided throughout the cell, causing the mobile ionic species to migrate in the direction of the blocking electrode. A layer depleted of mobile ions is formed close to the blocking electrode, which causes the current to decline over time gradually. This example shows how the current is calculated as a function of time till saturation level. This cell is polarised using d.c. voltage; in this case, we polarised the cell up to 0.92 before allowing it to self-discharge. The initial total draft (It) in the current vs. time figure is the sum of the improvement from ions and electrons. In contrast, the constant residual current (Ie) is exclusively attributable to the ionic current. The ionic transference number is thus provided by equation (2) and (3):
\(t_{ion\ =\ 1-}\frac{I\mathbb{e}}{I_{t}}\) (2)