Composite Cathode of NCM Particles and Li₃PS₄-LiI Electrolytes Prepared using the SEED Method for All-Solid- State Lithium Batteries

Li₇P₂S₈I (LPSI) electrolytes were directly produced on a cathode active material LiNi_1/3Mn_1/3Co_1/3O₂ (NMC) using the new liquid process which is named 'SEED method'. The formation of electrolytes on NMC was confirmed using scanning electron microscopy and energy dispersive X-ray mapping. The ionic conductivities of the LPSI electrolyte prepared by the SEED method were evaluated and the LPSI electrolyte showed 2.5 × 10⁻⁴ Scm⁻¹ at room temperature which is almost equal to that of the LPSI electrolyte prepared by the previous liquid-phase shaking process. All-solid- state cells composed of [90MNC⋅10LPSI composite | Li₃PS₄ | In-Li] were fabricated and the electrochemical properties of the cells were evaluated. The cell fabricated using this composite as cathode material exhibited enhanced performance in comparison with the cell using the cathode material prepared by hand mixing LPSI with NMC.