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

Abstract

We demonstrate a simple method to fabricate all solid state, thermally reduced Graphene Oxide (TRGO) microsupercapacitors (µ-SCs) prepared using the atmospheric pressure chemical vapor deposition (APCVD) and a mask-free axiDraw sketching apparatus. The Fourier transform infrared spectroscopy (FTIR) shows the extermination of oxygen functional groups as the reducing temperature (RT) increases, while the Raman shows the presence of the defect and graphitic peaks. The electrochemical performance of the µ-SCs showed cyclic voltammetry (CV) potential window of 0–0.8 V at various scan rates of 5–1000 mVs−1 with a rectangular shape, depicting characteristics of electric double layer capacitor (EDLC) behavior. The µ-SC with 14 cm−2 (number of digits per unit area) showed a 46% increment in capacitance from that of 6 cm−2, which is also higher than the µ-SCs with 22 and 26 cm−2. The TRGO-500 exhibits volumetric energy and power density of 14.61 mW h cm−3 and 142.67 mW cm−3, respectively. The electrochemical impedance spectroscopy (EIS) showed the decrease in the equivalent series resistance (ESR) as a function of RT due to reduction of the resistive functional groups present in the sample. Bode plot showed a phase angel of −85° for the TRGO-500 µ-SC device. The electrochemical performance of the µ-SC devices can be tuned by varying the RT, number of digits per unity area, and connection configuration (parallel or series).

Impact of Thermally Reducing Temperature on Graphene Oxide Thin Films and Microsupercapacitor Performance

“…This behaviour was allotted to the removal of resistive OFGs, i.e., the carboxylic acids attached to the surface edges resisting the flow of electrons [5] (confirmed by the increase in electrical conductivity as the reducing temperature increased). These OFGs also served as a passage for the ions to the bulk internal surface, as well as facilitating the fast redox processes occurring at or near the electrode surface, which can provide pseudocapacitance, as shown by our previously reported results [2,12]. Our electrochemical impedance spectroscopy (EIS) results showed a decrease in the solution resistance, further confirming the removal of the surface-edges functional group.…”

Two‐step electrodeposition of Hausmannite sulphur reduced graphene oxide and cobalt‐nickel layered double hydroxide heterostructure for high‐performance supercapacitor

“…The G and D peaks at 1595 and 1354 cm −1 , respectively confirm the successful integration of RGO‐S in the composite's material. The D peak is the k‐point phonon of A 1g symmetry 33 which can be attributed to the structural defects, edges, or the presence of functional groups. The G peak denotes the in‐plane stretching of the sp 2 carbon atom 34 .…”

A Review of Fabrication Technologies for Carbon Electrode-Based Micro-Supercapacitors

“…Vertically aligned graphitic nanofibers were grown using chemical vapour deposition, and their surface was then coated with ruthenium oxide thin films through an electrochemical deposition process; these coated fibres acted as electrodes in supercapacitors [140]. A solid-state micro-supercapacitor, with thermally reduced graphene oxide, was produced through atmospheric pressure chemical vapour deposition [141].…”