A Facile Polymer Interlayer for Lithium Stability in Lithium–Sulfur Batteries

Lithium–sulfur (Li–S) batteries are a promising next-generation battery chemistry, but the challenges that surround lithium metal anodes prevent it from being realized as a commercial technology. In this work, we address lithium stability via a facile, 5 μm thin PVDF–HFP and LiNO3 interlayer placed directly on the lithium anode. We created the interlayer with a simple blade casting technique that was performed under ambient conditions. It was then studied in Li–Li symmetric cells, showing stability through 500 h. Using post-mortem XPS, we found that a robust solid electrolyte interface with increased LiF content was formed in situ from the interlayer materials. This provided heightened stability compared to conventional cells without the interlayer. Additionally, we investigated the synergistic effect of the interlayer materials. Finally, using this interfacial layer in a Li–S coin cell battery provided a capacity of 858 mAh g–1 at 200 cycles, an increase of 32% compared to conventional Li–S cells without the interfacial layer. This work represents a step toward the stability of lithium metal anodes and their viability in commercial batteries.