Densified Li₆PS₅Cl Nanorods with High Ionic Conductivity and Improved Critical Current Density for All-Solid-State...

Solid electrolytes are receiving great interest owing to their good mechanical properties and high lithium-ion transference number, which could potentially suppress lithium dendrites. However, lithium dendrites can still penetrate solid electrolytes even at low current densities. In this work, a flat-surface Li₆PS₅Cl nanorod pellet with high density is achieved, which exhibits an ionic conductivity as high as 6.11 mS cm^-1 at 25 °C. The flat surface of the pellet is beneficial for the homogeneous lithium deposition, and the dense pellet microstructure can suppress the growth of lithium dendrites along the grain boundaries, leading to a significantly improved critical current density of 1.05 mA cm^-2 at 25 °C. The resultant dense Li₆PS₅Cl pellet is further employed in a LiCoO₂/Li₆PS₅Cl/Li all-solid-state lithium battery, showing an initial discharge capacity of 115.3 mAh g^-1 at 1C (0.35 mA cm^-2, 25 °C) with a capacity retention of 80.3% after 100 cycles.