With the increasing deman‎d for portable an‎d flexible electronic devices with high energy an‎d power density, developing next-generation lightweight an‎d flexible energy storage devices is of great importance. Flexible supercapacitors based on carbon cloths are one of the promising energy storage devices for this purpose. In this study, in the first work, binary manganese-cobalt oxides with different percentages were synthesized on the surface of carbon cloths using the hydrothermal method. In the second work, the surface modification of carbon cloths with binary manganese-cerium coatings was carried out. The morphology, structure, an‎d state of the formed surface oxides were investigated using various identification tests such as XPS, XRD, an‎d FE-SEM. The electrochemical properties of the prepared samples were investigated in a three-electrode system. The results showed that in the first work, the Co-Mn/CC sample (with 50% cobalt an‎d 50% manganese) performed better than the other samples, i.e. it had a higher supercapacitor capacity, power density, an‎d energy density. Subsequently, a true symmetric supercapacitor was fabricated with this electrode. The results of the electrochemical studies showed that the fabricated supercapacitor had a capacitance of 80.28 mF/cm an‎d also exhibited good stability, so that it retained more than 90% of its capacitance after 10,000 (ten thousan‎d) consecutive charge-discharge cycles. Similar to the first work, in the second work, the Ce-Mn/CC sample containing (equal amounts of manganese an‎d cerium) had better capacitive performance than the prepared samples. It showed higher supercapacitive capacity, power density, an‎d energy density than the other samples. The symmetrical two-electrode supercapacitor made with this electrode also had a capacitance of 43.233 mF/cm an‎d was able to maintain more than 80% of its capacity after 10,000 consecutive charge-discharge cycles. In the third work, carbon cloths were modified using manganese-cerium-cobalt ternary oxides. For this purpose, four electrodes containing ternary oxides with different percentages were prepared, an‎d the electrochemical test results showed that the ternary sample containing equal amounts of the three compounds had the best performance compared to the other ternary samples. Also, the performance of this electrode was better than that of the binary electrodes. Next, a real (two-electrode) flexible supercapacitor was prepared using the best electrode an‎d its capacitive behavior was investigated. Studies showed that the capacitance of this supercapacitor is 164.2 mF/cm2, which is about 2.1 times that of the supercapacitor made with a cobalt-manganese double electrode an‎d about 3.8 times that of the supercapacitor made with a cerium-manganese double electrode. The supercapacitor also had good flexibility an‎d was able to maintain more than 90% of its capacity after 10,000 cycles.

محمدمحسن مومني هامانه

مسعود عطاپور

اسماعيل حيدري , حسين فرخ پور , مسعود فرجي