Multi-heteroatom co-doped sodium alginate/sodium lignosulfonate hierarchical porous carbon aerogels for high-performance supercapacitors

Multi-heteroatom co-doped carbon aerogels featuring abundant micro/mesoporous structures are highly used as electrode materials for supercapacitors, showing excellent specific capacitance and cycle stability. In this study, the hierarchical porous carbon aerogel (BHPC-4) co-doped with heteroatoms containing nitrogen (3.23 atom%), oxygen (12.17 atom%), boron (10.09 atom%) and sulfur (0.74 atom%) was prepared with sodium lignosulfonate and sodium alginate as carbon precursors and ammonium pentaborate as boron source and activator. The material demonstrates an impressive specific capacitance of 381.0 F·g −1 at 1 A·g −1 in a three-electrode system with an electrolyte of 6 M KOH. In a symmetric supercapacitor, it has a high capacitance retention rate of 95.9 % and a coulomb efficiency of 97.2 % after 10,000 cycles at 5 A·g −1 . Remarkably, the symmetric supercapacitor achieves an energy of 15.1 Wh·kg −1 at 72.0 W·kg −1 . The study presents a novel approach to efficient use of renewable biomass to produce nitrogen, oxygen, boron and sulfur multi-heteroatom doped carbon aerogels for supercapacitors.