Performance Enhancement of the Li6PS5Cl‐Based Solid‐State Batteries by Scavenging Lithium Dendrites with LaCl3‐Based Electrolyte

Li₆PS₅Cl (LPSC) is a very attractive sulfide solid electrolyte for developing high-performance all-solid-state lithium batteries. However, it cannot suppress the growth of lithium dendrites and then can only tolerate a small critical current density (CCD) before getting short-circuited to death. Learning from that a newly-developed LaCl₃-based electrolyte (LTLC) can afford a very large CCD, a three-layer sandwich-structured electrolyte is designed by inserting LTLC inside LPSC. Remarkably, compared with bland LPSC, this hybrid electrolyte LPSC/LTLC/LPSC presents extraordinary performance improvements: the CCD gets increased from 0.51 to 1.52 mA cm^-2, the lifetime gets prolonged from 7 h to >500 h at the cycling current of 0.5 mA cm^-2 in symmetric cells, and the cyclability gets extended from 10 cycles to >200 cycles at the cycling rate of 0.5 C and 30 °C in Li|electrolyte|NCM721 full cells. The enhancing reasons are assigned to the capability of LTLC to scavenge lithium dendrites, forming a passive layer of Ta, La, and LiCl.