Metastable Decomposition Realizing Dendrite-Free Solid-State Li Metal Batteries

摘要

A stable interface and preventing dendrite-growth are two crucial factors torealize long-life all-solid-state Li batteries (ASSLBs) using sulfide-based solidelectrolytes (SEs) and Li metal anodes. But it remains a challenge to accomplishthe two factors simultaneously. Here, an effective strategy is reported to realizethis goal in Li-argyrodites via self-engineered metastable decomposition that isenabled by Si doping in Cl-rich argyrodites. It is shown that Cl atoms in the latticebecome metastable and are highly reactive with Li atoms. The locally deposited/grown Li crystal nuclei are thus depleted by the metastable Cl during electrochemicalcycling, in situ generating electrically insulated LiCl shells concentratedat the argyrodite grain boundaries. The shells in turn prevent the autochthonousLi redeposition and act as self-protective layers to restrain the continuousdecomposition in the interior argyrodite, that is, self-assembly of reactive-coresstable-shells to Li metal, thereby enabling an ultra-long life ASSLB using Li metalanodes at room temperature under relatively high current densities.