Derivation of an Iron Pyrite All-Solid-State Composite Electrode with Ferrophosphorus, Sulfur, and Lithium Sulfide as Precursors

In order to address the poor energy density of bulk all-solid-state lithium-ion batteries a new composite electrode preparation method is proposed. This study demonstrates the concurrent synthesis of the FeS 2 active material and a glass electrolyte which is similar to the (100-x)P 2 S 5 :xLi 2 S system of glass electrolytes. This is accomplished through the successive mechanochemical and thermal treatments of Fe 2 P, S, and Li 2 S. The composite electrode's ionic conductivity of 5.46 × 10 −5 S cm −1 at 60°C and specific energy of 1.2 Wh g −1 versus a lithium metal anode suggest that this method may provide a more intimate solid-solid interfacial contact between active material and glass electrolyte. The results of this study provide a completely new perspective on the preparation of all-solid-state composite electrodes.