## 3 Results and Discussion
### Electrical Resistivity  
The specific electrical resistivities of green and baked anodes are given in Figure 3. Replacing 3% of the coke with unmodified biocoke increased the electrical resistivity of the green anode compared to that of the standard anode. However, the increase in the resistivity of the corresponding baked anode was not significant. In addition, the change in the resistivity of the anodes produced with biocoke modified using A(1) and A(3) was quite small, both for green and baked anodes. Modifying the biocoke with A(3) even decreased the resistivity of the green anode (i.e., B3-A(3)3) slightly compared to the resistivity of the standard anode. This was not the case for the corresponding baked anode. The quality of coke used in anodes is decreasing. Industry-mixes cokes of different origin to obtain a mixture, which contains a reasonable amount of impurities that affect the reactivity of coke [6]; thus, blending at the industrial scale results in the non-homogeneity of the coke. Slight changes in properties are expected, even if they are produced under similar conditions and using the same raw materials. On the other hand, the resistivities of the anode containing biocoke modified with A(2) were high both for green and baked anodes (i.e., B3-A(2)3). Use of anodes with high electrical resistivity increases power consumption during electrolysis. These results can be explained based on the anode's density. Anodes with low density have high resistivities, since they are more porous compared to high-density anodes. Air in the pores of low-density anodes increases the resistivity. The enrichment of the surface functional groups of biocoke with the additives increases the wettability of biocoke by pitch, thus facilitating the penetration of pitch into the pores. Consequently, this lowers the electrical resistivity (Figure 2 and Table 3).  
Figure 2: Contact angles of the modified and unmodified biocokes.  
Figure 3: Electrical resistivity of the anodes before (**a**) and after (**b**) baking.  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**Sample**} & \multicolumn{6}{c}{**Carbon C1s Components (\%)**} \\ \cline{2-7}  & **Aromatic** & **Aliphatic** & **Ether Alcohol** & **Carbonyl** & **Carboxyl, Imide, Ester** & **Amine, Epoxy** \\ \cline{2-7}  & **C=C** & **C–C** & **C–O** & **C=O** & **COO/COON** & **CN** \\ \hline
**UMBC** & 89.8 & 0 & 1.5 & 1.2 & 1.2 & - \\ \hline
**BCM-A(1)** & 88.3 & 0 & 1.7 & 2.2 & 2.2 & - \\ \hline
**BCM-A(2)** & 56.24 & 25.43 & 5.41 & 1.7 & 2.07 & - \\ \hline
**BCM-A(3)** & 73.06 & 9.82 & 4.82 & 2.09 & 1.34 & \\ \hline
**Pitch** & 66.1 & 25.8 & 0.9 & 0.4 & 0.4 & 0.5 \\ \hline
**Coke** & 89.4 & 4.9 & 1.1 & 1 & 0.9 & - \\ \hline \multirow{2}{*}{**Simple**} & \multicolumn{6}{c}{Atomic Percentage} \\ \cline{2-7}  & \multicolumn{6}{c}{Heteroatoms} \\ \cline{2-7}  & **C (\%)** & **O (\%)** & **S (\%)** & **N (\%)** & **K (\%)** \\ \hline
**UMBC** & 93.8 & 4.9 & 0.1 & - & 1.1 \\ \hline
**BCM-A(1)** & 91.9 & 6.3 & - & - & 1.2 \\ \hline
**BCM-A(2)** & 92.41 & 7.59 & - & - & - \\ \hline
**BCM-A(3)** & 92.18 & 7.82 & - & - & - \\ \hline
**Pitch** & 94.8 & 3.6 & 0.1 & 2.2 & - \\ \hline
**Coke** & 97.3 & 2.5 & 0.2 & - & - \\ \hline \hline \end{tabular}
\end{table}
Table 3: Atomic percentages of the coke, pitch, and unmodified/modified biocokes.