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Three-dimensional (3D) carbon networks have been explored as promising capacitive materials thanks to their unique structural features such as large ion-accessible surface area and interconnected porous networks,thus enhancing both ions and electrons transport.Here,sustainable bacterial cellulose (BC) is used both precursor and template for facile synthesis of free-standing N,S-codoped 3D carbon networks (a-NSC) by the pyrolysis and activation of polyrhodanine coated BC.The synthesized a-NSC shows highly conductive interconnected porous networks (24 S · cm-1),large surface area (1 420 m2 · g-1) with hierarchical meso-microporosity,and high-level heteroatoms codoping (N:3.1 ％ in atom,S:3.2 ％ in atom).Benefitting from these,a-NSC as binder-free electrode exhibits an ultrahigh specific capacitance of 340 F · g-1 (24μF · cm-2) at the current density of 0.5 A · g-1 in 6 M KOH electrolyte,high-rate capability (71％ at 20 A · g-1) and excellent cycle stability.Furthermore,the assembled symmetrical supercapacitor displays a much short time constant of 0.35 s in 1 M TEABF4/AN electrolyte,obtaining a maximum energy density of 32.1 W · h · kg-1 at power density of 637 W · kg-1.The in situ multi-heteroatoms doping enables biocellulose-derived carbon networks to exploit its full potentials in energy storage applications,which can be extended to other dimensional carbon nanostructures.