Hierarchical porous carbon derived from wood tar using crab as the template: Performance on supercapacitor

Owing to intrinsic structural limitations, it is difficult to control the pore structure of biomass to synthesize hierarchical porous carbons (HPCs) to achieve high supercapacitor performance. As an inevitable by-product of the thermochemical conversion of biomass, wood tar exhibits good thermoplasticity and high-carbon content, and can be used as an alternative carbon source for biomass to prepare HPCs. To improve the utilization of wood tar, a facile synthetic route is proposed for preparing HPCs, based on a natural biological template method coupled with KOH activation. The HPCs possess favorable features in terms of high solid-carbon yield, high oxygen content (similar to 9 at%), large specific surface areas (626.43-2489.62 m(2) g(-1)), and an interconnected hierarchical porous structure, which greatly improved wettability and synergistically enable the construction of high-performance supercapacitors in aqueous and organic systems. The optimized HPC electrode exhibits a specific capacitance of 338.5 F g(-1) in a 6 M KOH electrolyte, and the constructed symmetric supercapacitors deliver high energy densities up to 9.9 Wh kg(-1) and 33.87 Wh kg(-1) in aqueous and organic electrolytes, respectively. This study provides an effective route for the utilization of wood tar and crab shell waste.