Multiple-heteroatom doped porous carbons from self-activation of lignosulfonate with melamine for high performance supercapacitors

A facile synthesis strategy by combination self-activation of biomass materials with heteroatom dopant in one-step is developed to fabricate porous carbons (NO-PCMs) doping with N, O, and S elements from direct carbonization of sodium lignosulfonate and melamine mixture. Two different types of active defects are constructed simultaneously through the decomposition of sodium lignosulfonate in NO-PCMs, exhibiting hierarchical porosity and abundant heteroatoms contents. The typical NO-PCMs displayed high specific capacitance (300 F g −1 at 0.1 A g −1 ) and outstanding cycling stability (99% capacitance retention after 10,000 charge/discharge cycles at 10 A g −1 ) in 6 M KOH electrolyte. Furthermore, the assembled symmetric supercapacitors exhibited high specific capacitance of 162 F g −1 at 20 A g −1 , 71% capacitance retention at current density up to 20 A g −1 , and possessed high specific energy density of 21.6 Wh kg −1 with an excellent power density of 92 W kg −1 operated in the wide voltage range of 1.8 V in 1 M Na 2 SO 4 aqueous electrolyte, demonstrating the broad prospects of biomass/biowaste being used to prepare electrode materials.