Electrical Conductivity. To measure the through plane electrical conductivity, wires were attached to each side of the composites (cut to 5 mm x 3.5 mm x 10 mm cuboids), using silver ink and epoxy silver paste to minimise the contact resistance, as shown in Figure (a). These were analysed using an N4L NumetriQ Phase Sensitive Multimeter and Impedance Analysis Interface over a 1 -10 6 Hz frequency range. The measured complex impedance (𝑍 * ) values were used to calculate the specific conductivity (𝜎) using: