LAUSR

Abstract The paper is devoted in the study of the simple method to study the performance of aqueous electrolytes, whereas the custom-made FBNC-700 (FB represents FAC-brown, N represents “nitrogen-self-doped,” C represents mesoporous-carbon materials, and 700 represents carbonization temperature.) was utilized as the electrode material, where the C4O6H4KNa solution was utilized as an aqueous electrolyte. The polarization curves was be used in the three-electrode system to conduct the voltage window preliminary selection of the C4O6H4KNa solution, the voltage window was 1.3 V (−0.8 V to 0.5 V). The concentration had minimal effects on the voltage window. The method is faster and more efficient way to study the performance of aqueous electrolytes for supercapacitors. In the 2 M C4O6H4KNa solution, the FBNC-700 displayed a 97 F g−1 specific capacitance at the current density of 0.5 A g−1 in the two-electrodes tests. Also, following 5000 cycles at a current density of 1 A g−1, the FBNC-700 had good stability with 76.22% capacitance retention.