Outstanding Electrochemical Performance of Planar On-chip Micro-supercapacitors Based on Nitrogen and Oxygen Co-doped Graphene Quantum Dots at High Scan Rates

Abstract

In recent years, researchers continue optimizing and innovating in the selection of supercapacitor electrode materials and fabrication processes. In this paper, the fabrication process and electrochemical performance of an all-solid-state planar on-chip micro-supercapacitors (POMSs) with nitrogen and oxygen co-doped graphene quantum dots as electrode material will be demonstrated. Graphene quantum dots (GQDs) electrode films were prepared by a modified liquid-air interface self-assembly method, and patterned by photolithography. The resulting POMSs achieved an area capacitance of 25.53 μFcm−2, and its areal energy density and areal power density are 3.55nWh cm−2 and 8.79 μW cm−2 correspondingly. It is worth noting that the POMSs have excellent rate capability and can maintain outstanding performance at ultrahigh scan rate of 10000 V s−1. The POMSs have a short time constant which is 3.16 μs, and the capacitance characteristics can be maintained over 99.1% in 10000 cycles of charge and discharge at a scan rate of 5000 V s−1 in the cyclic stability test.