The optimum conditions to obtain the maximum specific surface area of SGR and FCR were temperature 20.88 °C, salinity 24.07‰, and body size 263.81 g, under which the maximal value reached 3.69%day− 1 and 0.869 respectively.
At 800 °C and a KOH/MEGO mass ratio of 6.5, a maximum specific surface area of 3100 m2/g was obtained and a high specific capacitance of 172 F/g (at 1 A/g constant current and 3.5 V maximal voltage) was measured in a two-electrode cell with a-MEGO electrodes in an organic electrolyte.
Maximal difference in specific surface of clays is found in the horizon Elcg, where AC has the highest content of free iron.
The maximal volume of specific surface area at 350°C (Figure 4) indicates that this annealing temperature is more optimal for obtaining powders with minimal particle size and free carbon content.
The maximal specific capacitance of 256 F g−1 and high specific surface capacitance of 0.51 F m−2 were achieved at 0.2 A g−1.
The supercapacitors with the carbon electrode reached maximal specific capacitances of 340 F g−1 and high specific surface capacitance of 52.7 μF cm−2 at the current density of 0.1 A g−1, good rate capability (231 F g−1 at 10 A g−1) and good cycling stability (92% capacitance retention over 3000 cycles).
Maximal porosity (Table 2, V p) and specific surface area (S BET) are characteristics for sample 2 calcined at T t = 480 °C.
CCF, HCF and ACF have their surface oxygen-containing groups of 1.52, 0.8 and 0.45 mM m−2 and specific surface areas of 0.33, 0.65 and 1.19 m2 g−1, but yield their maximal power densities of 606, 858 and 990 mW m−2, respectively.
The specific surface area and porosity largely depend on the nature of the polysaccharide, and maximal SBET value of 43 m2/g is for nHAp/agar.
When the amount of CuO-doped activated carbon with a specific surface area of 2460 m2 g−1 reached 2%, the single electrode average specific capacitance can reach the maximal value of 210 F g−1, about 20% higher than the one used pure activated carbon as electrode material.
