Mechanochemically synthesized pyrite and its electrochemical behavior as cathode for lithium batteries

This study presents a simple and scalable synthesis of pyrite (FeS 2 ) starting from S and Fe powders, which involves high-energy ball milling of precursor powders followed by a thermal treatment. The formation of the desired product was confirmed by X-ray diffraction, Raman spectroscopy, thermogravimetric analysis, and X-ray photoelectron spectroscopy. After the synthesis, spherical FeS 2 nanoparticles of ~ 85 nm in size were obtained, with a highly crystalline face-centered cubic structure and no secondary phases. The synthesized material was tested as cathode material for lithium batteries. The cathodes delivered good electrochemical lithium storage properties, such as a reversible capacity as high as 470 mAh g −1 even after 120 cycles and a good rate capability. Furthermore, aspects regarding the reaction mechanism and common electrochemical features of Li/FeS 2 batteries are discussed.