One/Two-Step Contribution to Prepare Hierarchical Porous Carbon Derived from Rice Husk for Supercapacitor Electrode Materials.

Grain processing generates vast amounts of agricultural byproducts, and biomass porous carbon electrode materials based on this have attracted broad research interests. Rice husk (RH) is one of the promising feedstocks owing to its good abundance and cheap price. Here, a RH-based porous carbon (RHPC) material was successfully prepared using first-step carbonization and second-step decalcification. The influence of carbonization temperature and decalcification treatment on the structure and electrochemical properties of the RH-based carbon materials were investigated. Thermogravimetric analysis, hydrogen element analysis, scanning electron microscopy, X-ray diffraction, and electrochemical performance tests were used to characterize and analyze the prepared RH-based carbon materials. After carbonization at 1000 °C (RH-1000) and decalcification treatment, RHPC-1000 showed the highest specific surface area of 643.48 m 3 /g and the largest pore volume of 0.52 cm 3 /g, which were about 1.8 times and 2.5 times that of RH-1000, respectively. RHPC-1000 also possessed a high capacitance retention capability of 97.2% after 10 000 charge-discharge cycles. The results demonstrated the excellent capacitive behavior and superior electrochemical performance of RHPC-1000. In summary, this study reveals a simple and effective preparation method of biomass porous carbon for supercapacitor electrode materials and provides new insight into the high-value utilization of waste biomass resources.