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Using renewable biomass precursors to develop high-performance carbon electrodes is a promising approach for the advancement of supercapacitors. This work proposes a feasible strategy to prepare self-supporting flexible porous carbon nanofibers by electrospinning and carbonizing the mixture of cuttlefish ink, polyacrylonitrile (PAN) and polymethyl methacrylate (PMMA). The impacts of cuttlefish ink precursor on the structure, elemental composition, and capacitance properties of carbon nanofibers have been studied. Herein, the unique structural advantage of cuttlefish ink can significantly optimize the porous structure of carbon nanofibers. Due to the hierarchical porous structure, large specific surface area, hollow channels and high nitrogen content, the carbon nanofibers offer a high specific capacitance of 364.8 F g−1 at 0.5 A g−1 current density, alongside desirable rate performance and cycle life. Furthermore, the carbon nanofiber electrode performs good mechanical flexibility. The flexible solid-state supercapacitor based on this electrode exhibits 14.1 Wh kg−1 energy density at 0.4 kW kg−1 power density, and 97.8% capacitance retention after 5000 cycles. The favorable capacitive properties make this carbon nanofiber material a potential candidate for supercapacitor electrodes. [Display omitted] • Electrospun porous carbon nanofibers (CPP–CNF) were prepared from cuttlefish ink. • CPP-CNF features hierarchical pores and hollow channels. • CPP-CNF is mechanically flexible with superior capacitive performance. • The flexible supercapacitor achieves high energy density and cycling stability. [ABSTRACT FROM AUTHOR]

Achieving high specific surface area and ion accessibility in graphene-based electrodes with a high mass loading for supercapacitors poses a significant challenge because strong π-π stacking of graphene sheets often blocks the access of electrolyte ions to active sites. Herein, we report a novel protocol to prepare free-standing laminated graphene/carbon nanofiber films as high areal mass-loading electrodes through a layer-by-layer electrospinning technique. The unique laminated structure of graphene/carbon nanofiber thin films can enhance electrolyte penetration and increase transportations of ions/electrons. The symmetric supercapacitors (SCs) using the as-obtained graphene/carbon nanofiber films as electrodes reach areal specific capacitance of 1536 mF cm−2 at a current density of 1 mA cm−2. Most importantly, the areal energy density of the SCs can reach 0.22 mWh cm−2 at a power density of 1 mW cm−2 with a high areal mass loading of 24 mg cm−2. The exceptional electrochemical properties of the laminated graphene/carbon nanofiber films render them promising materials for electrodes in SCs. [Display omitted] • Laminated graphene/CNFs were prepared via layer-by-layer electrospinning. • The unique laminated structure enhances ions accessibility at high mass loading. • The assembled symmetric supercapacitor exhibits high areal specific capacitance. [ABSTRACT FROM AUTHOR]