Low temperature synthesis of crystalline pyrite FeS2 for high energy density supercapacitors

Abstract

Herein, we report a low-temperature synthesis of crystalline pyrite-FeS₂ through a solid-state annealing route, which was achieved using FeOOH, a metastable precursor, in the presence of H₂S gas. The as-synthesized pyrite FeS₂ was employed as an electrode for fabricating high energy density supercapacitors. The device delivered a high specific capacitance of 51 mF cm⁻² at 20 mV s⁻¹ and showed a superior energy density of 30 μW h cm⁻² at a power density of 1.5 mW cm⁻².