Excellent electrochemical performance of all-solid-state planar on-chip micro-supercapacitors with narrow interdigital electrode configuration

Abstract

As a popular direction of research in micro-energy storage devices, improving the comprehensive performance of all-solid-state planar on-chip micro-supercapacitors (MSCs) has received increasing attention. Graphene quantum dots (GQDs) are a new type of nano-scale electrode materials that can improve the electrochemical performance of devices. In addition, the doping of nitrogen/oxygen heteroatoms can further improve the electrochemical activity of the electrode materials. In this paper, nitrogen-oxygen co-doped graphene quantum dots (NO-GQDs) were used as electrode materials, and a modified liquid-air interface self-assembly method was used to fabricate the electrode films. Finally, the MSCs with narrow interdigital electrode configuration were prepared by photolithography with an electrode width/interdigital gap of 3 μm/1 μm. The prepared MSCs have excellent electrochemical performance, including an area capacitance of 150.63 μF cm−2, an energy density of 20.92 nWh cm−2, a power density of 175.49 μW cm−2, a relaxation time constant of 3.53 μs, and a capacitance retention of 90.42%. As shown by the results, the combination of NO-GQDs and narrow interdigital electrode configuration provides a significant improvement in the comprehensive electrochemical performance of the all-solid-state planar on-chip MSCs.