The fact that the specific capacity was greater than 0.75 V in the first cycle and greater than 1.0 V in the subsequent cycles could be ascribed to the faradic capacitance on the surface or edge site of the EG. A similar phenomenon can be found in graphene nanosheets [35].
Rsei and Csei, which are related with the resistance and capacitance of the electrode surface [27], are in parallel.
Comparing the change in capacitance of the skin surface (minus the baseline) between the two groups, product P was better than product A in treating AE.
Thus, studies of the activated carbons [29, 30, 31, 32] and activated carbon nanofibers [33] showed that after some critical value (in most of cases around 1500 m2/g) capacitance becomes independent of the surface area.
This is due to the larger surface capacitance of the highly polarized ERGO surface, which was mentioned earlier in the "FESEM and EIS" section.
The dependence of the capacitance from the surface area is varied by way of preparation, origin of precursors and electrolyte species, textural characteristics and surface functionality of carbon materials.
The dependence of the gravimetric capacitance from the surface area of the studied carbons is depicted in Fig. 6b.
Specifically, the surface specific capacitance of the edged-graphene-sheet-covering surface was 146mF/m22, while that of the basal-planes-wrapping surface was 16 mF/m2.
From comparison of the ratios of the specific capacitances with those of the surface areas due to pores with sizes larger than certain values, the minimum size of the pores able to host the electro-adsorbed ions at the double layer is deduced; it results to be 0.56 0.58 nm for BF4−, 0.63 0.65 nm for Et4N+, 0.75 0.76 nm for Pr4N+ and 0.9 1 nm for Bu4N+.
The greater leakage current density at higher BaTiO3 content was caused by the larger capacitance and the surface roughness of hybrid dielectric layer.
