A new method for preparing excellent electrical conductivity carbon nanofibers from coal extraction residual

This work developed a cost-effective and environmentally benign method for preparing high electrical conductivity carbon nanofibers (CNFs) from coal extraction residuals. The electrical conductivity of the CNFs prepared with PAN and 10.00 wt%, 30.00 wt%, and 50.00 wt% residual extracted tar (RET) increases by 70.89%, 164.31%, and 193.22% in comparison with conventional pure PAN-based CNF at the carbonization temperature of 1000 °C. The results of electrochemical impedance spectroscopy have shown that the total resistance for 50.00 wt% and 30.00 wt% RET-based CNFs prepared at the reaction temperature of 1000 °C was 0.61 Ω and 0.73 Ω, respectively, which is lower than that of coal extracted tar (CET)-based CNF and PAN-based CNFs. Raman analysis indicates that the 50.00 wt% RET-based CNF shows the lowest relative intensity of −0.953 and the highest degree of the ordered carbon structure. According to SEM results, fewer defects were observed in the carbon structure of RET-based CNFs. The cross-linking structure in 50.00 wt% RET can contribute to the improvement of the electrical conductivity of CNFs, which is consistent with the observation of Raman results. The GC-MS analysis results reveal that the aromatic and phenolic concentration in RET is 37.91% and 176.69% higher compared with those in CET. Both aromatic and phenolic concentrations in CNF precursor favor the formation of CNFs with fewer defects and thus lead to a higher electrical conductivity in CNF. The GC-MS results present consistency with those of Raman, SEM, and electrochemical performance measurements.