Silicon-Based Composite Anodes for All-Solid-State Lithium-Ion Batteries Conceived by a Mixture Design Approach

Silicon-based anodes composed of micrometric Si, graphite (MAG), LiI-Li₃ PS₄ solid electrolyte (LPSI), and carbon nanofiber (CNF), which can be prepared by straightforward manual grinding, are proposed in this study. The relation between composition and performance of the anodes is investigated through the mixture design approach, which allows discrimination of the effect of each component and also the combined effect of the components on the end performance. By increasing the fraction of LPSI in the anode, the capacity of the electrode is improved, and the best performance is obtained when the Si/MAG/LPSI ratio is 15 : 15 : 70. This composite integrated with 5 wt % CNF exhibits a capacity above 1200 mAh g^-1 throughout 50 cycles in a bulk-type all-solid-state battery with LPSI as the electrolyte. Scanning electron microscopy (SEM) confirms that the presence of LPSI suppresses the aggregation of Si and improves the ratio of Si available for lithiation/delithiation.