Two-Dimensional Hexagonal-Shaped Mesoporous Carbon\nSheets for Supercapacitors

Abstract

Two-dimensional mesoporous\nhexagonal carbon sheets (MHCSs) have\nbeen prepared via a chemical vapor deposition method employing mesoporous\nMg­(OH)₂ hexagonal sheets as the template and acetylene\ngas as the carbon precursor. MHCSs with porosity in the micropore–mesopore\nrange have a high specific surface area of 1785 m²·g^–1. The hierarchical microporous–mesoporous pore\nstructure enables rapid ion transport across the hexagonal carbon\nsheets, resulting in superior electrochemical performance. The MHCS\nelectrodes showed a maximum specific capacitance of 162 F·g^–1 at 5 mV s^–1 using the electrolyte\n1-ethyl-3-methylimidazolium bis­(trifluoromethylsulfonyl)­imide (EMIM-TFSI).\nMHCS symmetric coin cells exhibited a maximum energy density of 67\nWh·kg^–1 at 0.5 A·g^–1 and a maximum power density of 14.97 kW·kg^–1 at 10 A·g^–1.