Pseudocapacitive quantum dots confined in sacrificial g-C3N4 derived carbon nanosheets for high performance ionic liquid-based supercapacitors

Abstract

Assembling supercapacitors (SCs) using high-voltage ionic liquid (IL) as electrolyte is an effective strategy to enhance the energy density of SCs. Herein, a novel pseudocapacitive quantum dots (QDs)-based electrode with superior electrochemical behaviors in IL electrolyte has been put forward. Remarkably, FeOOH QDs (FQDs) are effectively confined in a two-dimensional (2D) nanospace supported by porous N-doped carbon (PNC) derived from graphitic carbon nitride (g-C3N4). Beneficial from the abundant active sites and high surface wettability, the resultant FQDs/PNC electrode exhibits sufficient redox reaction and favorable electrochemical kinetics in IL electrolyte. As a result, it can deliver a large specific capacitance of 210.6 F g−1 and still retain 82.2% of its initial capacitance after 10,000 cycles.