Synthesis of high ionic conductivity Li6PS5Cl solid electrolyte by second sintering process

Argyrodite-type solid electrolyte have attracted great attention due to its high ionic conductivity and stability to lithium anode. In this experiment, argyrodite-type Li6PS5Cl was prepared by the solid-state method. The Li6PS5Cl solid electrolyte prepared by the solid-state sintering process has more pore and defects, resulting in lower ion conductivity of the electrolyte. The highest ionic conductivity was only 9.58×10-4 S cm-1. In order to decrease the defects in the Li6PS5Cl, a new type of second sintering process is used. The highest ionic conductivity obtained by this new process was up to 3.19×10-3 S cm-1, which was a relatively high value in currently reported. Industrial Computed Tomography (CT) technology was an advanced characterization method to observe the quantity, size, and distribution of defects inside the sample without any damage. In this experiment, industrial CT was used to detect the pores in Li6PS5Cl., finding that the second sintering process successfully reduces the quantity and size of pores in Li6PS5Cl solid electrolyte, uniforming the distribution of pores thus improving the ion conductivity of the Li6PS5Cl solid electrolyte. This new preparation and characterization method might provide a new idea for the further research of Li6PS5Cl.