Biomass Hierarchical Porous Carbonized Typha angustifolia Prepared by Green Pore-Making Technology for Energy Storage

The cost-effective biomass-derived carbon with high electrochemical performance is highly desirable for the sustainable development of advanced energy storage devices. In this manuscript, Typha angustifolia with a large output and loose porous characteristics was selected as the raw material of biomass. In the synthesis process, KHCO₃, which is more environmentally friendly, is used as a pore-forming agent, and the low-cost, easy-to-clean fluxing agent NaCl is used to assist the pore-forming process. Based on the analysis of thermogravimetric-infrared test results, the calcination procedure of porous carbon was designed reasonably, so that the functions of the pore-forming agent and fluxing agent could be fully exerted. Its high electrochemical performance is attributed to combined contributions from high surface area and hierarchical porous structures. The as-prepared carbon also showed an outstanding capacitance of 317.2 F/g at a current density of 1 A g^-1 and a high capacitance retention of over 97.83% after 5000 cycles at a current density of 4 A g^-1. This work provides an outstanding renewable candidate and a feasible route design strategy for the fabrication of high-performance electrodes.