Comparison of the heteroatoms-doped biomass-derived carbon prepared by one-step nitrogen-containing activator for high performance supercapacitor

Heteroatoms-doped biomass-derived carbon materials (HBC), a new task and hotspot of the current energy research, especially supercapacitor, have featured with low cost and rich sources with enhanced physical, chemical and electrical properties compared with those of pure counterparts. Nevertheless, converting the biomass into high-performance carbon materials by green chemical activators and dopants is still imperatively needed. Herein, a simple and cost-effective one-step method was proposed, using different nitrogen-containing compounds (NH4Cl, (NH4)(2)CO3 and urea) as both activation agent and dopant, to prepare nitrogen-doped biomass-derived hierarchical porous carbon materials (HPCs). The effect of nitrogen-containing compounds on the electrochemical performance of HPCs was also studied. Among them, NH4Cl is proved to be the porogen with the minimum collapse of pollen grain and urea can be identified as the most effective N dopant. Furthermore, the prepared HPC-urea (HPC-U) electrode deliver the highest specific capacitance of 300 F g(-1) at 1 A g(-1) and rate performance of 50% from 1 to 50 A g(-1) in three electrode system, while HPC-NH4Cl possesses the maximum capacitance retention rate of 95.2% after 10,000 cycles. In addition, HPC-U based SCs exhibits the highest energy density (14.3 Wh kg(-1)). Notably this work may provide a certain guideline for choosing N dopants and porogens to prepare biomass-derived carbon materials for the target application.

Automated summary

This study proposes a simple and cost-effective one-step method to prepare nitrogen-doped biomass-derived hierarchical porous carbon materials using different nitrogen-containing compounds as activation agent and dopant. Among them, urea is identified as the most effective N dopant, while NH4Cl is the porogen with the minimum collapse of pollen grain. The prepared electrodes show promising electrochemical performance in terms of specific capacitance, rate performance, capacitance retention rate, and energy density. This work may guide the selection of N dopants and porogens for preparing biomass-derived carbon materials for specific applications.