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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]

Although high-rate, long-cycle energy storage devices play a crucial role in the field of energy storage, they are relatively under-reported. This work reports the preparation of fibrous porous carbons ultra-high specific surface area of 3384 m2g-1 derived from medical waste degreased cotto. As electrode material for supercapacitors, the resulted porous carbons demonstrate an ultra-high specific capacitance of 505.5 F g−1 at 0.5 A g−1 in a three-electrode system with 6 M KOH as electrolyte. Assembled symmetric supercapacitors show a specific capacitance of 403.84 F g−1 at 0.5 A g−1 and 294.95 F g−1 at 20 A g−1, with a capacity retention rate of 73.62 %, impressively retaining 82.66 % of the capacity after 300000 cycles at 10 A g−1. The average capacity loss is minimal, at 0.000557 % per cycle. The as-assembled zinc-ion hybrid capacitors (ZIHCs) demonstrate a high energy density of 69.33 Wh kg−1 at 2400 W kg−1 in 2 M ZnSO 4 electrolyte and retain 99.3 % capacity after 120000 cycles at 7 A g−1, suggesting the excellent long cycling stability. These outstanding performances demonstrate a promising solution for recycling and utilizing medical waste-degreased cotton in energy storage devices, also addressing the research gap in high-rate, long-cycle applications. • Medical decreased waste cotton is efficiently transformed into porous carbons. • Porous carbons exhibit an ultra-high specific surface area of 3384 m2g-1. • As For supercapacitors (SCs), it exhibits high capacitance of 505.5 F g−1. • After 300000 cycles, SCs maintain a high-capacity retention rate of 82.66 %. • After 120000 cycles, the ZIHCs maintain a high-capacity retention rate of 99.3 %. [ABSTRACT FROM AUTHOR]

Herein, a kind of hydroxyl and sulfonyl-containing diamine 2,2-bis[4-(3-hydroxy-4-aminophenoxy)phenyl]sulfone (BHAPS) was first synthesized and polymerized with pyromellitic dianhydride (PMDA) to obtain poly(amic acid) (PAA) solution. Then, the PAA nanofibers were fabricated by electrospinning technology, which were further thermally treated at 300 °C for imidization, 450 °C for rearrangement and a certain final temperature for carbonization to obtain carbon nanofibers (CNFs). The PAA concentration, carbonization temperature and thermal rearrangement time were separately optimized, and the HPI-CNF-20-2-800 exhibited better electrochemical properties. Next, the HPI-CNF-20-2-800 was chemically activated with KOH to enhance specific surface area. The preferred A-HPI–CNF–1/3 demonstrated a specific capacitance maximum of 335.0 F g−1 at 0.5 A g−1, with a 73 % capacitance retention at 10 A g−1. Furthermore , the SC device was symmetrically assembled with self-supporting A-HPI–CNF–1/3 membranes, which showed a maximum energy density of 10.42 Wh kg−1 at a power density of 250.0 W kg−1. In addition, the capacitance retention rate of the SC reached 99.94 % even after 50,000 charge/discharge cycles at a current density of 1 A g−1. Thus, this work reports a new precursor to prepare N, O, S co-doped active CNFs with better electrochemical performance, which will provide a reference for the preparation of co-doped self-supporting SC electrodes. • A new kind of diamine monomer containing hydroxyl and sulfonyl was synthesized. • The N, O, S co-doped activated carbon nanofibers were prepared. • The capacitive performance of self-supporting electrode was effectively boosted. [ABSTRACT FROM AUTHOR]