Preparation of High-Performance Enteromorpha Prolifera–Based Porous Carbons by Nitrogen Modification and Their Electrochemical Performance

Abstract

This study presents a novel method to improve the electrochemical performance of porous carbons (PCs) by simply adjusting the elemental composition of their precursors with nitrogen-rich materials as additives. Nitrogen-modified enteromorpha prolifera–based (EP-based) PCs are prepared from EP and urea (or melamine). Overall, compared with the control PC without nitrogen modification, their pore structures and surface chemical properties present similar improvement. When used in supercapacitors, their specific capacitances increase by approximately 22% due to their significant development of mesopores at 2.5–7.0 nm, which increases the effective surface areas. With an appropriate amount of nitrogen-containing or oxygen-containing functional groups maintaining surface wettability, the notable increase of graphitized N improves their conductivity. Due to the higher graphitization degrees, their resistances are reduced. With more mesopores transporting ions, they exhibit excellent high-rate capacitive performance. Moreover, they show remarkable long cycle performance with the specific capacitance retention of larger than 92% after 10,000 cycles.