PAN-derived electrospun nanofibers for supercapacitor applications: ongoing approaches and challenges

The increasing demand for high-performance supercapacitors stimulates the rapid development of separators and electrodes. PAN-derived nanofibers via electrospinning with one-dimensional morphology, tunable nanostructure, mechanical flexibility, self-functionalities and those that can be added onto them have witnessed the intensive development and extensive applications of supercapacitors. However, the conventional PAN-derived carbon nanofibers are generally featured with rather inferior electrical conductivity and lower specific surface area. Beyond that, PAN-derived carbon nanofibers normally exhibit unsatisfactory electrochemical performance in supercapacitors. So far, several strategies have been proposed, by some of which, conspicuous success has been achieved in addressing the above key issues. Here, a comprehensive review on recent advances of the use of PAN-derived carbon nanofibers as the electrode materials for supercapacitors are provided with a focus on strategies to improve their electrochemical performances, and the basic scientific principles involved in these preparation processes. Next, the recent application progress of PAN-derived nanofibers as the electrode separators for supercapacitors is introduced. Finally, we put forward a series of critical challenges in the above research area and propose some correlative ideas for future research.