Electrodeposition Coupled with Electrochemical Activation for Constructing High-Capacitance Carbon Quantum Dot-Based Films on Carbon Cloth as Electrodes

Abstract

Carbon quantum dots (CQDs) have sparked notable research interest in energy storage because of their excellent conductivity, tunable surface chemistry, environmental friendliness, and low production cost. However, the exploration of the intrinsic electrochemical activity of CQDs is very limited and further improvement for the activity of CQDs is still a challenge. Therefore, a scalable CQD-based film was fabricated on N 2 plasma-treated carbon cloth (CC) using electrodeposition, which released an areal specific capacitance of 168.8 mF cm −2 and a mass-specific capacitance of 844 F g −1 at 1 mA cm −2 that increased to 572.5 mF cm −2 and 2862 F g −1 after electrochemical activation, respectively. The mechanism analysis revealed that the enhanced capacitance activity of the CQD-based film was mainly attributed to the optimization of edge sites and an increase in graphitized sp 2 carbon structures in CQDs as well as the graphene-like structure of the CQD-based film. The solid-state symmetrical supercapacitors assembled using two activated CQD-based films could release a maximum energy density of 17.04 μWh cm −2 and 0.28 mWh cm −3 under a power density of 200 mW cm −2 and 3.33 mW cm −3 and good cycle stability in a PVA/H 2 SO 4 electrolyte. Such a facile strategy used for the fabrication of CQD-based films has broad development prospects for the flexible design of advanced carbon electrodes for energy-storage microdevices.

Zero‐Dimensional Carbon Nanomaterials for Electrochemical Energy Storage

“…CQDs and GQDs have received widespread attention in supercapacitors. [157][158][159][160][161] The application of GQDs as an ideal electrode materials for supercapacitors was reported by Liu et al [157] These GQDs were synthesized from GO powder using a facile one step solvothermal method. They prepared both symmetric and asymmetric systems.…”

“…CQDs and GQDs have received widespread attention in supercapacitors [157–161] . The application of GQDs as an ideal electrode materials for supercapacitors was reported by Liu et al [157] .…”