Portable and Flexible High Performance All-solid-state Planar Micro-supercapacitors Based on Nitrogen and Oxygen Co-doped Graphene Quantum Dots

Abstract

The rapid development of intelligent technology puts forward higher requirements for portable and flexible energy storage devices. In this paper, nitrogen and oxygen co-doped graphene quantum dots were used as electrode material of flexible planar micro-supercapacitors (PMSCs) and the electrode/gap width was 6 μm/2 μm. Electrochemical performance of the flexible devices was investigated at different bending angles with scan rates of 0.01 V/s to 10000 V/s. When bending 75°, the area capacitance and the energy density were 2.61 μF cm−2 and 0.36 nWh cm−2 at the scan rate of 0.01 V/s, and the power density was 173.66 μW cm−2 at the scan rate of 10000 V/s. When bending 0°, the area capacitance and energy density were the same as that when bending 75°, and the power density was 198.36 μw cm−2. The output current of the two flexible devices was 200 μA when bending 75° and 250 μA when bending 0°. The capacitance retention was 87.5% when bending 75° and 90.4% when bending 0° at the scan rate of 500 V/s after 10000 cycles. The results indicated that the bending has little effect on the electrochemical performance of the flexible PMSCs.