Finger Number and Device Performance: A Case Study of Reduced Graphene Oxide Microsupercapacitors

Abstract

Microsupercapacitors (MSCs) are recognized as suitable energy storage devices for the internet of things (IoTs) applications. Herein is described the work conducted to assess the areal energy and power densities of MSCs with 2, 10, 20, and 40 interdigital finger electrodes on a fixed device footprint area (the finger interspacing is fixed at 40 μm, and the finger width and length are allowed to vary to fit the footprint area). The MSCs are based on reduced graphene oxide (rGO) materials and fabricated with a spin‐coating and etch method. The performance evaluation indicates a strong dependency of areal capacitance and energy density on the number of fingers, and the maximum (impedance match) power density is also influenced to a relatively large extent, whereas the average power density is not sensitive to the configuration parameters in the present evaluation settings (scan rate 20–200 mV s−1 and current density of 100 μA cm−2). For the rGO‐based devices, the equivalent distributed resistance may play an important role in determining the device resistance and power‐related performance.

Novel Thermally Reduced Graphene Oxide Microsupercapacitor Fabricated via Mask—Free AxiDraw Direct Writing

“…From previous studies, it seems that more digits per unit area results in a better electrochemical performance, which includes more power and energy. This seems to be true for a certain range of digits per unit area due to external factors such as the removal of active electrode mass which increases as the number of digits increase [ 35 ] (see Table S1 , Figure S2 ) and the electric field strength which increases as the number of digits increases due to the edging effect [ 21 ]. The areal capacitance of the TRGO-300 determined from the total surface area (area of the entire µ-SC including the interspace) and effective area (excluding the interspace) is displayed in Figure S3 .…”