Multichannel carbon nanofiber anode materials derived from polyacrylonitrile/cellulose acetate nanofibers with improved performance in lithium-ion batteries

Electrospun carbon nanofibers (CNFs) have remarkable properties such as high surface area, a three-dimensional conductive interconnected network, porous and self-supporting structure, making them promising anode materials for advanced lithium-ion batteries (LIBs). However, the development of a well-organized porous architecture is crucial to further enhance their electrochemical performance. In this study, multichannel CNFs (m-CNFs) were fabricated via electrospinning of polyacrylonitrile (PAN) and cellulose acetate (CA) blend solutions followed by thermal treatment processes namely, stabilization and carbonization. Initially, solid CNFs (s-CNFs) were fabricated by using PAN alone in order to investigate the influence of thermal treatment processes on both morphology and electrochemical performance. Additionally, the effect of PAN:CA ratio on the morphology of the PAN/CA based CNFs was studied by varying the PAN:CA weight ratios in the electrospinning solutions. The phase separation behavior of CA within the continuous PAN matrix facilitated the formation of multichannel porous nanofibers and inter-fiber junctions after thermal treatment. Increasing CA content yielded a more prominent multichannel structure formation with intense fiber junctions. Electrochemical evaluation of the self-supporting CNF electrodes revealed that s-CNFs carbonized at 650 °C exhibited a higher specific capacity of 538 mAh g^-1after 100 cycles at 50 mA g^-1, compared to those carbonized at 550 °C and 750 °C. In contrast, m-CNFs anode showed remarkable cycling capacity as 634 mAh g^-1after 100 cycles at 50 mA g^-1and superior rate capability as 226 g^-1at a high current density of 2 A g^-1. As a result, a unique multichannel porous structure obtained under optimized thermal treatment conditions contributed to accelerated ion transport kinetics and improved accessibility of lithium storage sites. This study highlights the potential of multichannel CNFs as efficient, self-supporting anode materials for high-performance LIBs.