Development of PANI/FeS2/MnO2 Composite Electrode Materials for High‐Performance Supercapacitors

Abstract Polyaniline (PANI) has unique physical and chemical peculiarities, so it has been widely researched in the field of energy storage. However, its structure is easy to be damaged during charging and discharging, which seriously affects its application. PANI/FeS 2 /MnO 2 composite materials were successfully prepared by an easy combination of chemical precipitation and chemical oxidative polymerization. The electrochemical test results manifested that the specific capacitance of PANI/FeS 2 /MnO 2 4 : 1 : 3 was 580 F/g at 1 A/g, and had great cyclic stability (capacitance retention rate was 85.2 % after 10000 cycles at 5 A/g). It was because that reticular structure shortened the ion transport path. On the other hand, it was able to effectively mitigate the volume change during long‐term charging and discharging, thus improving the cycling stability. In addition, PANI/FeS 2 /MnO 2 4 : 1 : 3 as the positive and activated carbon (AC) as the negative, an asymmetrical supercapacitor was assembled with a maximal energy density of 37.93 Wh/kg when its power density was 0.85 kW/kg. At the same time, the device possessed a long cycle life (the capacitance conservation rate was 82 % after 5000 cycles at 5 A/g). This excellent performance is due to the excellent synergy between the PANI, FeS 2 and MnO 2 . This study opens a new way to investigate polyaniline‐based composite electrode materials.