Fabrication of Assembled FeS2 Nanosheet and Application for High-Performance Supercapacitor Electrodes

Abstract

To overcome the low-energy-densitylimitation of supercapacitors,we aimed to achieve a material with a high specific capacitance bymanipulating the nanostructure of FeS2, which comprisesthe most abundant and affordable elements. In this study, nanosheet-assembledFeS(2) (NSA-FeS2) was fabricated using a novelmethod. Sub-micron droplets of sulfur particles stabilized with polyvinylpyrrolidonewere formed in silicone oil medium, and Fe-(CO)(5) was absorbedand reacted on the surface to form core-shell particles, ES/[Fe],with a sulfur core and an iron-containing outer shell. The high temperaturetreatment of ES/[Fe] produced NSA-FeS2, in which pyriteFeS(2) nanosheets grew and were partially interconnected.In a three-electrode system, the as-prepared NSA-FeS2 andNSA-FeS2/polyaniline (PANI) composites exhibited specificcapacitances of 763 and 976 Fg(-1), respectively,at a current density of 0.5 Ag-1, with correspondingcapacitance retentions of 93 and 96% after 3000 charge-dischargecycles. The capacitance retention of the NSA-FeS2/PANIcomposites was 49% when the current density was increased from 0.5to 5 Ag-1. Notably, the obtained specific capacitancesexhibited the highest values in pure FeS2 and FeS2-based composites, indicating the significant potential for the utilizationof iron sulfide in pseudocapacitive electrode materials.