▎ 摘　　要

The electrical conductivity and capacitive behavior of supercapacitors (SCs) were found to be improved by the synergistic effects of the violet laser treatment (VLT) of nitrogen doped reduced graphene oxide (N-rGO) as an electrode and 1.5% (w/v) p-phenylenediamine (PPD)-containing KOH as a redox electrolyte. The SC employing VLT treatment on the N-rGO electrode with 2 M KOH (N-rGO-V) represented a greater specific capacitance of up to 263.6 F g-1 compared to N-rGO in the same electrolyte, which was 232.2 F g-1 at 0.25 A g-1. To further improve the charge-storage ability, the SC using the VLT treatment on the N-rGO electrode with the PPD addition into 2 M KOH (NrGO-V-PPD) revealed the highest specific capacitance, reaching 593.7 F g-1 at 0.25 A g-1 or 28.6% compared to N-rGO in the same redox electrolyte (N-rGO-PPD). Furthermore, the capacitance retention after 10,000 cycles of N-rGO-V-PPD remained at 62% (265 F g-1 at 100 mV s-1), which is still significantly higher than that of other samples, and the VLT technique provided a lower self discharge rate. According to the physical characterizations, N-rGO-V-PPD has a rougher and larger surface area due to the exfoliated graphene oxide sheets and has a modest increase in the number of quinone/carbonyl functional groups in the graphene material, resulting in better electrical conductivity. All of these could be contributing factors to the performance improvement. Lastly, PPD provides redox mediators such as H+ and e- in the redox electrolyte, which are anticipated to improve the charge storage.