Electrical property evolution in the graphitization process of activated carbon by high-pressure sintering

Activated carbon was treated at 5.0 GPa up to 1600 °C, and the electrical property evolution in the graphitization process was investigated. The change of structure results in the corresponding electrical property transition. For the samples at low high-pressure sintering temperature, the variable-range hopping is the main electrical transportation mechanism. The graphitized activated carbon is a semimetal while the high-pressure sintering temperature is lower than 1300 °C and behaves non-Fermi-liquid property at higher sintering temperature. The ratio of resistivity at ∼5.0 and ∼300.0 K versus high-pressure sintering temperature is drastically decreasing near the graphitization temperature, which indicates that the insulator–metal transition occurs in the sintering temperature range of 900–1000 °C.

Graphical abstractThe structural evolution of activated carbon in the graphitization process results in the corresponding electrical property transition. The electrical transportation mechanism changes from variable-range hopping across the approximatively linear ρ–T relationship to non-Fermi-liquid property with increasing high-pressure sintering temperature. There is an insulator–metal transition between non-graphitization region and near-graphitization region.Figure optionsDownload full-size imageDownload as PowerPoint slide