Graphite oxide paper as a polarizable electrical conductor in the through-thickness direction

Graphite oxide (GO) paper is a polarizable electrical conductor in the through-thickness direction, as shown by alternating-current electrical testing performed with decoupling of the volumetric and interfacial contributions. The solid part (69 vol%) of the dark brown paper (112–358 μm thick) exhibits carbon/oxygen atomic ratio 2.0, and interlayer spacing 8.60 Å. At 50 Hz and 2 MHz respectively, the in-plane conductivity is 0.07 and 2.5 S/m, the through-thickness conductivity is 6.7 × 10⁻⁶ and 4.8 × 10⁻³ S/m, the through-thickness relative dielectric constant is 915 and 91, the specific capacitance of the interface with an electrical contact is 18.3 and 1.1 μF/m², and the areal resistivity of this interface is 1.5 × 10⁵ and 1.0 × 10² Ω cm². The conductivity is due to slightly incomplete intercalation (but without residual graphite), as shown by a weak X-ray diffraction peak at interlayer spacing 4.33 Å. The interface contributes, but the volumetric capacitance/resistance dominates. The decrease of κ with increasing frequency (50–200 Hz) is attributed to the functional-group-related dipole friction. The increase of the through-thickness conductivity with increasing frequency is attributed to the decreasing excursion of the charge carriers and the consequent decrease in the chance of the carriers to encounter interfaces.