Dual template method to prepare hierarchical porous carbon nanofibers for high-power supercapacitors

Abstract

Hierarchical porous carbon nanofibers serving as electrode materials are prepared through carbonization and hydrofluoric acid treatment of polyacrylonitrile-based electrospinning involving dual templates. The hierarchical porous structures are synergistically tailored by varying template contents in the spinning solution. The carbon nanofibers prepared from the electrospinning of polyacrylonitrile containing 15/15 wt.% polymethylmethacrylate/tetraethyl orthosilicate exhibit the largest specific surface area (699 m² g⁻¹) and microporous volume (0.196 cm³ g⁻¹). In 6 M KOH electrolyte, a symmetrical supercapacitor equipped with the hierarchical porous carbon nanofibers demonstrates its high-end specific capacitance of 170 F g⁻¹, superior rate capability, and high-power density output up to 14.7 kW kg⁻¹. Cycling evolution indicates capacitance fading is only 5.8 % of initial capacitance at a current density of 1 A g⁻¹ even after 8,000 cycles. The excellent electrochemical performances of the carbon nanofiber are mainly ascribed to the optimized pore size distributions of both micropores and mesopores and the unique hierarchical pore structures possessed by abundant micropores.