On-Chip Planar Interdigital Micro-Supercapacitors Based on Reduced Graphene Oxide with Superior Rate and Charge-Discharge Capabilities

Abstract

Reduced graphene oxide (RGO) thin films were prepared on silicon substrates by a modified liquid-air interface self-assembly method and a hydroiodic acid reduction method. Planar on-chip micro-supercapacitors with interdigital structure electrodes (RGO-POMSs) were prepared by photolithography and gold sputtering on the electrode lugs. Area capacitance of interdigital RGO-POMSs was 51.72 μF cm−2. They also had 0.0072 μW h cm−2 of energy density and 59.78 μW cm−2 of power density. Due to the short ion transport path caused by interdigital electrodes, the charge discharge time constant of the device was only 0.029 ms, which could realize rapid charge discharge. In addition, they also had good cycle stability and could maintain 82% capacitance after 4500 cycles of charge and discharge. The cyclic voltammetry test showed that the device still worked well at the ultra-high scan rate of 10,000 V s−1. This showed that RGO-POMSs had considerable prospects in the research field of micro energy storage devices.