Improvement of the rate capability of all-solid-state cells with Fe-based polysulfide positive electrode materials by modifying the microstructure

Abstract

We successfully prepared an Fe- and Li-containing polysulfide positive electrode material (Li₈FeS₅–Li₂FeS₂ composite) that shows a high specific capacity (>500 mA h g⁻¹) with improved rate capability in all-solid-state cells. High-resolution TEM analysis indicated the coexistence of small crystallites of high-conductivity Li₂FeS₂ and FeS, as well as low-crystallinity Li₂S, in the composite, and this microstructure is responsible for the improved battery performance.