Fabrication of multiscale porous carbon nanofibers via phase separation of copolymer-based blends for high-performance sodium-ion battery anodes

Multiscale porous carbon materials, which possess both microporous and mesoporous structures, are highly promising as anode materials for sodium-ion batteries. These structures effectively enhance sodium ion storage and diffusion, leading to improved battery performance. However, the mass production and commercialization of conventional multiscale porous carbon materials are hindered by complex manufacturing processes and challenges in precise pore structure control. In this study, we introduce a straightforward method for the synthesis of multiscale porous carbon nanofibers via electrospinning and carbonization of a polymer solution comprising polyacrylonitrile (PAN)-polymethyl methacrylate (PMMA) block copolymer and polystyrene (PS). The resulting carbon nanofibers were utilized as anode materials in sodium-ion batteries and exhibited a high specific capacity of 409.1 mAh g⁻¹ at a current density of 0.1 A g⁻¹. Moreover, these fibers displayed outstanding rate capability, maintaining 45 % of their initial capacity even at an elevated current density of 5 A g⁻¹. The capacity decay rate was impressively low at only 25.2 % after 1000 charge-discharge cycles at a current density of 0.2 A g⁻¹, confirming their outstanding stability.