Magnesium Hydroxide Templated Hierarchical Porous Carbon Nanosheets as Electrodes for High-Energy-Density Supercapacitors
Yafen Tian, Xiangyu Zhu, Muhammad Abbas, Daniel W. Tague, Melissa A. Wunch, John P. Ferraris, Kenneth J. Balkus
Abstract
Hierarchical porous carbon nanosheet (HPCN) materials of different thicknesses were fabricated on Mg(OH)2 substrates utilizing a one-step chemical vapor deposition (CVD) approach. The templated carbon nanosheets are closely packed hierarchical nanostructures possessing high surface areas varying from 1323 to 1978 m2·g–1. Symmetrical electrochemical double-layer capacitors (EDLCs) were constructed using the HPCN and demonstrated a high specific capacitance of 205 F·g–1 at 5 mV/s using 1-ethyl-3-methylimidazolium bis (trifluoromethylsulfonyl)imide (EMIM-TFSI) as an electrolyte. The energy density was 86 Wh·kg–1, and a power density of up to 16.57 kW·kg–1 was observed. After 5000 charge–discharge cycles at 10 A·g–1, the supercapacitor retained 90% of its initial capacity. This illustrates the great stability of the templated mesoporous carbon sheets for supercapacitors.