Facile assembly of solid-state on-chip planar micro-supercapacitors based on graphene quantum dots with overall electrochemical properties

• Published in: Ferroelectrics 2024-10, Vol.618 (13-14), p.2330-2338
• Main Authors: Zhang, Guang-Yu, Gao, Yu, Wang, Feng-Lei, Jiao, Jun-Chao, Qiao, Jia-Hui, Zhou, Xin-Wei
• Format: Article
• Language: English
• Subjects: Capacitance; Electrical resistivity; Electrochemical analysis; Electrochemistry; Electrons; Energy storage; Frequency response; Graphene; graphene quantum dots; modified liquid-air interface self-assembly; Oxygen plasma; Photolithography; Planar micro-supercapacitors; Plasma etching; Quantum dots; Relaxation time; Self-assembly; Solid state; Supercapacitors; Time constant
• ISSN: 0015-0193; 1563-5112
• DOI: 10.1080/00150193.2024.2324709

To promote the rapid development of high-performance energy storage devices, graphene quantum dots (GQDs) have attracted extensive attention due to their excellent properties such as high electrical conductivity, high specific surface area, high mobility and good dispersion in various solvents. Here, the solid-state on-chip planar micro-supercapacitors (PMSCs) based on the GQDs were facilely assembled by liquid-air interface self-assembly, photolithography, oxygen plasma etching and gold sputtering. The fabricated PMSCs delivered an area capacitance of 2.83 µF cm −2 , an energy density of 0.40 nWh cm −2 and a power density of 49.64 µW cm −2 . The PMSCs allowed for operation at the scan rate up to 10,000 V s −1 , indicating ultrahigh rate capability, and had the relaxation time constant of 197 µs, revealing excellent frequency response capability and the retention of initial specific capacitance of about 94% after 10,000 cycles at the scan rate of 500 V s −1 , demonstrating good sustainable electrochemical stability. This work paves the way for new prospective applications of the GQDs in the portable-wearable micro-nano energy storage field.