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).
