Research on Morphology Regulation and Energy Storage Performance of High-Performance Polypyrrole

Supercapacitors, as a new type of energy storage device, have attracted major attention due to their large energy storage capacity, long cycle life and environmental friendliness. Thereinto, the electrode material directly affects its energy storage performance, the electrode materials with good electrochemical performance were the focus of this paper. Thus, PPy was prepared by chemical oxidation in this study. According to XRD and SEM patterns, it was found to have low crystallinity, amorphous properties, high purity, spherical shape and uniform size distribution. It was also found that the size of PPy nanoparticles decreased with the increase of ammonium persulfate (APS), but the increase of APS had no effect on the crystal structure. In addition, the electrochemical performance of polypyrrole was investigated by changing the ratio of pyrrole to APS (1:0.5, 1:1, 1:2). When the ratio of Py to APS was 1:1, it was observed through the CV curve that PPy had the largest CV closed integral curve area and the best electrochemical performance when the scanning rate was 30mV/s. Meanwhile, the GCD and specific capacitance curves also showed that PPy had the longest discharge time and the largest specific capacity (212.3 F/g) when the current density was 0.5A/g and the voltage window was 0–0.6 V. In addition, PPy at this ratio showed good rate capability (65% range from 1 to 20 A/g) and stability (84% after 5000 cycles). Furthermore, the specific capacitance of the assembled device is as high as 257.9 mF/cm2 at 0.3 mA/cm2. By connecting 9 devices in series, a high voltage of 7.4V can be achieved. Meanwhile, when 6 devices are connected in series, the capacity can reach six times that of a single device, presenting a promising practical application prospect.