The Role of Metal Disulfide Interlayer in Li–S Batteries

Recently many observations related to the catalytic effects of layered metal disulfide versus polysulfide electrochemistry were documented. In this work, we investigated the reactivity of layered WS2 in a Li–S battery and observed a chemical reaction involving the removal of W ions by polysulfides. The presence of metallic tungsten nanoparticles in the sulfur cathode is the result of W ion oxidation reaction and subsequent recrystallization during cycling. In situ Raman spectroscopy and ex situ transmission electron microscopy were used in order to clarify the reaction mechanism.