Plasma Synthesis of Spherical Crystalline and Amorphous Electrolyte Nanopowders for Solid-State Batteries

Here, we demonstrate the theory-guided plasma synthesis of high purity nanocrystalline Li_3.5Si_0.5P_0.5O₄ and fully amorphous Li_2.7Si_0.7P_0.3O_3.17N_0.22. The synthesis involves the injection of single or mixed phase precursors directly into a plasma torch. As the material exits the plasma torch, it is quenched into spherical nanocrystalline or amorphous nanopowders. This process has virtually zero Li loss and allows for the inclusion of N, which is not accessible with traditional synthesis methods. We further demonstrate the ability to sinter the crystalline nanopowder into a dense electrolyte membrane at 800 °C, well below the traditional 1000 °C required for a conventional Li_3.5Si_0.5P_0.5O₄ powder.