Biomass-based porous carbon from trachycarpus fortunei silk with the hierarchical oxygen-enriched structure for high performance flexible all-solid-state supercapacitor

Hierarchical porous carbons with diverse pore scales are commonly chosen as electrode materials for high-performance supercapacitors due to their excellent electrochemical properties. Herein, a novel synthetic method, dilute H2SO4 pretreatment coupling with subsequent KOH activation, is adopted to prepare hierarchical oxygen-enriched porous carbon using trachycarpus fortunei silk (TFSPC) waste as the raw material. The opti-mized TFSPC2 possesses a 2049 m2 g-1 specific surface area, 1.58 cm3 g-1 total pore volume, and 22.54 at% oxygen-containing doping. Benefiting from such characteristics, the TFSPC2 electrode exhibits an excellent specific capacitance of 469 F g-1 at 0.5 A g-1 and remarkable cycling stability of only 4.94% capacitance decay even after 20000 uninterrupted cycles in a 6 M KOH electrolyte. Furthermore, the assembled flexible symmetric supercapacitor device TFSPC2//TFSPC2 achieves a high energy density of 14.60 Wh kg-1 in a potential range of 0-1.3 V when the power density is 320 W kg-1. More importantly, the TFSPC2//TFSPC2 device demonstrates superior mechanical flexibility and maintains 88.70% capacity retention even through 2000 cycles (90 degrees) of reduplicative bending/recovering. The research provides a low-cost, green, and renewable strategy for the synthesis of hierarchical porous carbons for supercapacitors.

Automated summary

In this study, hierarchical oxygen-enriched porous carbon was synthesized using trachycarpus fortunei silk waste as the raw material. The carbon material exhibited excellent electrochemical properties, including high specific capacitance and remarkable cycling stability. The assembled supercapacitor device showed a high energy density and superior mechanical flexibility.