Regulating Li deposition behavior at anodic interface induced by SbF3 electrolyte additive in all-solid-state Li metal batteries

The PEO-LLZTO composite solid electrolyte (CSE) is considered as one of the most promising solid-state electrolytes (SSEs). However, there is still a serious problem caused by dendrite penetration due to the uneven deposition of Li on the interface. Construction of Li alloy-rich artificial interfacial layers is proved to be an ideal solution to hinder Li dendrite growth. However, traditional coating methods often result in thick and uneven interfacial layer, causing unsatisfied Li plating behavior. In this work, commercial SbF3 is firstly used as a solid-state electrolyte additive to in-situ construct an ultrathin and uniform Li-Sb alloy-rich artificial interfacial layer, which optimized the Li deposition behavior. The Li//Li symmetric cell with SbF3@CSE solid electrolyte exhibits a high working current density of 1.5 mA·cm−2 and an extended cycle life about 980 h at 0.2 mA·cm−2. Moreover, the LiFePO4//Li cell shows a greatly improved cycle stability and Coulombic efficiency compared with Blank CSE, in which the LiFePO4/SbF3@CSE/ Li delivers a stable cycle performance at 1C for nearly 200 cycles (91.3% capacity retention), and it also exhibits superior rate capability of about 140 mAh·g−1 at 1C. These results demonstrate the modified electrolyte holds large potential for all-solid-state lithium metal battery applications.