A stable solid-state lithium battery with a fluorine-rich interfacial layer electrolyte membrane

Unstable contact interface, undesired side reactions and severe lithium dendrites in the lithium metal batteries have seriously compromised its safety and hindered its wider commercialization. Here, we design an artificial interfacial layer to eliminate side reactions at the lithium/electrolyte interface and the dendrite formation by coating the surface of the composite electrolyte membrane with another PVDF-HFP polymer containing ZnF2 powder based interfacial layer, which is used for the in-situ generation of a hybrid artificial SEI layer of LiF between Li metal anode and electrolyte. The ionic conductivity of the composite electrolyte with the ZnF2 interfacial layer is 2.1 × 10−4 S cm−1, and the stable electrochemical window is 5.0 V. The Li||Li symmetrical cell can be cycled consistently over than 800 h at 0.2 mA cm−2. For the LiFePO4||Li cell, the discharge capacity of 132.2 mAh g−1 can be obtained after 300 cycles at 0.5 C, corresponding to 93.6% capacity retention. This structural design strategy of artificial interfacial layers has great potential for realizing stability and wide application of lithium metal batteries.