Stabilizing the interphase between Li and Argyrodite electrolyte through synergistic phosphating process for all-solid-state lithium batteries

Among solid electrolytes, sulfides have been considered as one of the most promising candidates due to their soft nature and high ionic conductivity. However, the interphase problem between Li metal and sulfide electrolytes has been a concern. As indicated by the density functional theory (DFT) calculations, Li3PO4 and Li3N possess the highest interface energy and the highest interfacial adhesion energy towards Li metal, respectively. A two-step synergistic phosphating process involving the reaction of H3PO4 and LiNO3 on the Li surface generates a Li3PO4-Li3N hybrid interphase. The designed interphase with high ionic conductivity and low electronic conductivity exhibits excellent stability against lithium metal. The symmetric cell incorporated with modified Li could cycle over 200 h at a current density of 1 mA cm−2 and a cut-off capacity of 1 mAh cm−2. The all-solid-state lithium batteries (ASSLBs) with the modified Li anodes shows good cycling and rate performances. This work provides a perspective of realizing practical modification of lithium metal in ASSLBs.