Green Synthesis of Nitrogen-doped Porous Carbon Derived from Rice Straw for High-performance Supercapacitor Application
Zenghua Xu, Ximing Zhang, Liang Yue, Hongjian Lin, Shen Zhang, Jianglong Liu, Caidi Jin, Ungyong Choe, Kuichuan Sheng
Abstract
Hierarchical structural carbon with properly modulated compositions and porosity is essential for energy storage capacity. Here, N-doped porous carbon was synthesized using abundant rice straw under the sequential hydrothermal treatment and calcination by KHCO3 in the presence of melamine. The activation with KHCO3 resulted in about a 50% increase in the yields of porous carbons and performance comparable to that of KOH. The extra additional melamine not only introduces the N-containing functional groups but also enhances the mesoporosity and specific surface area (2786.5 m2 g–1). Meanwhile, wettability and conductivity are improved. The obtained N-doped porous carbon exhibits outstanding capacitance of 317 F g–1 at 1 A g–1. The fabricated symmetric supercapacitor displays a stable cycling performance (99.4% retention after 5000 cycles), a reasonable rate performance, and the maximum specific energy of 18.4 W h kg–1. Our research provides a promising method for effectively converting biowaste into energy storage materials through green synthetic strategy.