Multistage Template-Oriented Design and Tailoring of the Hierarchical Porous Biocarbon Materials for High-Performance Supercapacitors

Interfacial regulation is crucial for the enhancement of the specific surface area and supercapacitive performance in porous carbon materials. However, traditional porous carbon obtained through potassium hydroxide activation is confronted with a complicated preparation process. Herein, hierarchical porous biocarbons (HPBC) were facilely prepared by using the multiscale template method and wheat flour as a precursor without any activation. A spherical SiO₂ template and wheat flour can be closely combined by gelatinization so as to effectively confine and spatially orient carbon materials. Benefiting from the hierarchical porous structure achieved through the use of templates at different sizes, HPBC-3 has the best electrochemical performance of 223.6 F·g^-1 at 1 A·g^-1. Moreover, the assembled HPBC-3//HPBC-3 symmetrical supercapacitor demonstrates a remarkable energy density of 15.6 W h·kg^-1 and exhibits exceptional cycling performance with a capacitance retention rate of 106% after 5000 cycles. The results fully demonstrate the promising application of the obtained hierarchical porous carbon in supercapacitors.